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While debugging another issue today, I found out that my TX queue is
reported as stopped for 4294907392 ms (49.7 days), on a machine that
had been up for four minutes.
bnxt_en 0002:01:00.0 eth0: NETDEV WATCHDOG: CPU: 28: transmit queue 23 timed out 4294907392 ms
4294907392 is not an elapsed time. It is the value of jiffies at that
moment: INITIAL_JIFFIES is 4294667296, which leaves jiffies 59 seconds
short of wrapping.
dev_activate() runs transition_one_qdisc() over every TX queue, which
resets trans_start to 0, and then stamps only queue 0 through
netif_trans_update().
Stamp jiffies instead. A queue stopped across dev_activate() now gets a
full watchdog_timeo of grace, and is still reported if it is stopped
that long.
Fixes: 9b36627acecd ("net: remove dev->trans_start")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20260825-trans_start-v2-1-286b4d6d70cb@debian.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Marek Szyprowski reported a deadlock during system resume when virtio_net
driver is used.
The deadlock occurs because netif_device_attach() is called while holding
dev->tx_global_lock (via netif_tx_lock_bh() in virtnet_restore_up()).
netif_device_attach() calls __netdev_watchdog_up(), which now also tries
to acquire dev->tx_global_lock to synchronize with dev_watchdog().
This recursive lock acquisition results in a deadlock.
Fix this by removing the tx_global_lock acquisition from netdev_watchdog_up().
The critical state (watchdog_timer and watchdog_ref_held) is already
protected by dev->watchdog_lock, which was introduced in the blamed commit.
Fixes: 8eed5519e496 ("net: watchdog: fix refcount tracking races")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/netdev/a443376e-5187-4268-93b3-58047ef113a8@samsung.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260622110108.69541-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge in late fixes in preparation for the net-next PR.
Conflicts:
net/tls/tls_sw.c
406e8a651a7b ("net: skmsg: preserve sg.copy across SG transforms")
79511603a65b ("tls: remove dead sockmap (psock) handling from the SW path")
drivers/net/ethernet/microsoft/mana/mana_en.c
f8fd56977eeea ("net: mana: guard TX wq object destroy with INVALID_MANA_HANDLE check")
d07efe5a6e641 ("net: mana: Use per-queue allocation for tx_qp to reduce allocation size")
https://lore.kernel.org/ajAPXu-C_PuTgV-a@sirena.org.uk
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Blamed commit converted the untracked dev_hold()/dev_put() calls
in the watchdog code to use the tracked dev_hold_track()/dev_put_track()
(which were later renamed/interfaced to netdev_hold() and netdev_put()).
By introducing dev->watchdog_dev_tracker to store the
reference tracking information without adding synchronization
between netdev_watchdog_up() and dev_watchdog(), it enabled the
race condition where this pointer could be overwritten or freed
concurrently, leading to the list corruption crash syzbot reported:
list_del corruption, ffff888114a18c00->next is NULL
kernel BUG at lib/list_debug.c:52 !
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 91 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound linkwatch_event
RIP: 0010:__list_del_entry_valid_or_report.cold+0x22/0x2a lib/list_debug.c:52
Call Trace:
<TASK>
__list_del_entry_valid include/linux/list.h:132 [inline]
__list_del_entry include/linux/list.h:246 [inline]
list_move_tail include/linux/list.h:341 [inline]
ref_tracker_free+0x1a7/0x6c0 lib/ref_tracker.c:329
netdev_tracker_free include/linux/netdevice.h:4491 [inline]
netdev_put include/linux/netdevice.h:4508 [inline]
netdev_put include/linux/netdevice.h:4504 [inline]
netdev_watchdog_down net/sched/sch_generic.c:600 [inline]
dev_deactivate_many+0x28c/0xfe0 net/sched/sch_generic.c:1363
dev_deactivate+0x109/0x1d0 net/sched/sch_generic.c:1397
linkwatch_do_dev net/core/link_watch.c:184 [inline]
linkwatch_do_dev+0xd3/0x120 net/core/link_watch.c:166
__linkwatch_run_queue+0x3a5/0x810 net/core/link_watch.c:240
linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
process_scheduled_works kernel/workqueue.c:3397 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
This patch has three coordinated parts:
1) Add dev->watchdog_lock and dev->watchdog_ref_held to serialize watchdog operations.
2) Remove netdev_watchdog_up() call from netif_carrier_on():
This ensures netdev_watchdog_up() is only called from process/BH context
(via linkwatch workqueue dev_activate()), allowing us to use
spin_lock_bh() for synchronization.
3) Synchronize watchdog up and watchdog timer:
Protect netdev_watchdog_up() with tx_global_lock and watchdog_lock.
Only allocate a new tracker in netdev_watchdog_up() if one is
not already present.
In dev_watchdog(), ensure we don't release the tracker if the
timer was rescheduled either by dev_watchdog() itself or concurrently
by netdev_watchdog_up().
Fixes: f12bf6f3f942 ("net: watchdog: add net device refcount tracker")
Reported-by: syzbot+381d82bbf0253710b35d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a26b751.c25708ab.1b19ef.0013.GAE@google.com/T/#u
Tested-by: syzbot+3479efbc2821cb2a79f2@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260611152737.2580480-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add qstats_backlog_sub() and qstats_backlog_add() helpers
and use them instead of open-coding them.
These helpers use WRITE_ONCE() to prevent store-tearing.
Also use WRITE_ONCE() in fq_reset() and qdisc_reset()
when sch->qstats.backlog is cleared.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260510091455.4039245-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Helpers to increment or decrement sch->q.qlen, with appropriate
WRITE_ONCE() to prevent store tearing.
Add other WRITE_ONCE() when sch->q.qlen is changed.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260510091455.4039245-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The protodown functionality allows user space to turn off the carrier of
a net device:
# ip link add name dummy1 up type dummy
# ip link add name macvlan1 up link dummy1 type macvlan mode bridge
# ip link set dev macvlan1 protodown on
$ ip -br link show dev macvlan1
macvlan1@dummy1 DOWN 0a:5c:a3:05:c7:86 <NO-CARRIER,BROADCAST,MULTICAST,UP>
Different applications can set different protodown reasons, which
prevents an application from turning on the carrier of a net device as
long as others want it down:
# ip link set dev macvlan1 protodown_reason 1 on
# ip link set dev macvlan1 protodown_reason 2 on
# ip link set dev macvlan1 protodown off
Error: Cannot clear protodown, active reasons.
# ip link set dev macvlan1 protodown_reason 2 off
# ip link set dev macvlan1 protodown off
Error: Cannot clear protodown, active reasons.
# ip link set dev macvlan1 protodown_reason 1 off
# ip link set dev macvlan1 protodown off
$ ip -br link show dev macvlan1
macvlan1@dummy1 UP 0a:5c:a3:05:c7:86 <BROADCAST,MULTICAST,UP,LOWER_UP>
Unfortunately, this mechanism is not very useful when the carrier of a
net device can be toggled by toggling the carrier of its lower device:
# ip link set dev macvlan1 protodown on
$ ip -br link show dev macvlan1
macvlan1@dummy1 DOWN 0a:5c:a3:05:c7:86 <NO-CARRIER,BROADCAST,MULTICAST,UP>
# ip link set dev dummy1 carrier off
# ip link set dev dummy1 carrier on
$ ip -br link show dev macvlan1
macvlan1@dummy1 UP 0a:5c:a3:05:c7:86 <BROADCAST,MULTICAST,UP,LOWER_UP>
Obviously, this is not the intended behavior and it is unlikely to be
relied on by anyone. In fact, it is a problem for applications like FRR
that use protodown with macvlan on top of a bridge as part of Virtual
Router Redundancy Protocol (VRRP).
Solve this by preventing a net device configured with protodown on from
gaining carrier by making netif_carrier_on() a NOP when protodown is
turned on.
Output with the patch:
# ip link add name dummy1 up type dummy
# ip link add name macvlan1 up link dummy1 type macvlan mode bridge
# ip link set dev macvlan1 protodown on
$ ip -br link show dev macvlan1
macvlan1@dummy1 DOWN 0a:5c:a3:05:c7:86 <NO-CARRIER,BROADCAST,MULTICAST,UP>
# ip link set dev dummy1 carrier off
# ip link set dev dummy1 carrier on
$ ip -br link show dev macvlan1
macvlan1@dummy1 DOWN 0a:5c:a3:05:c7:86 <NO-CARRIER,BROADCAST,MULTICAST,UP>
# ip link set dev macvlan1 protodown off
$ ip -br link show dev macvlan1
macvlan1@dummy1 UP 0a:5c:a3:05:c7:86 <BROADCAST,MULTICAST,UP,LOWER_UP>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260507105906.891817-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR (net-7.0-rc5).
net/netfilter/nft_set_rbtree.c
598adea720b97 ("netfilter: revert nft_set_rbtree: validate open interval overlap")
3aea466a43998 ("netfilter: nft_set_rbtree: don't disable bh when acquiring tree lock")
https://lore.kernel.org/abgaQBpeGstdN4oq@sirena.org.uk
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Whenever a TEQL devices has a lockless Qdisc as root, qdisc_reset should
be called using the seq_lock to avoid racing with the datapath. Failure
to do so may cause crashes like the following:
[ 238.028993][ T318] BUG: KASAN: double-free in skb_release_data (net/core/skbuff.c:1139)
[ 238.029328][ T318] Free of addr ffff88810c67ec00 by task poc_teql_uaf_ke/318
[ 238.029749][ T318]
[ 238.029900][ T318] CPU: 3 UID: 0 PID: 318 Comm: poc_teql_ke Not tainted 7.0.0-rc3-00149-ge5b31d988a41 #704 PREEMPT(full)
[ 238.029906][ T318] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 238.029910][ T318] Call Trace:
[ 238.029913][ T318] <TASK>
[ 238.029916][ T318] dump_stack_lvl (lib/dump_stack.c:122)
[ 238.029928][ T318] print_report (mm/kasan/report.c:379 mm/kasan/report.c:482)
[ 238.029940][ T318] ? skb_release_data (net/core/skbuff.c:1139)
[ 238.029944][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
...
[ 238.029957][ T318] ? skb_release_data (net/core/skbuff.c:1139)
[ 238.029969][ T318] kasan_report_invalid_free (mm/kasan/report.c:221 mm/kasan/report.c:563)
[ 238.029979][ T318] ? skb_release_data (net/core/skbuff.c:1139)
[ 238.029989][ T318] check_slab_allocation (mm/kasan/common.c:231)
[ 238.029995][ T318] kmem_cache_free (mm/slub.c:2637 (discriminator 1) mm/slub.c:6168 (discriminator 1) mm/slub.c:6298 (discriminator 1))
[ 238.030004][ T318] skb_release_data (net/core/skbuff.c:1139)
...
[ 238.030025][ T318] sk_skb_reason_drop (net/core/skbuff.c:1256)
[ 238.030032][ T318] pfifo_fast_reset (./include/linux/ptr_ring.h:171 ./include/linux/ptr_ring.h:309 ./include/linux/skb_array.h:98 net/sched/sch_generic.c:827)
[ 238.030039][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
...
[ 238.030054][ T318] qdisc_reset (net/sched/sch_generic.c:1034)
[ 238.030062][ T318] teql_destroy (./include/linux/spinlock.h:395 net/sched/sch_teql.c:157)
[ 238.030071][ T318] __qdisc_destroy (./include/net/pkt_sched.h:328 net/sched/sch_generic.c:1077)
[ 238.030077][ T318] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)
[ 238.030089][ T318] ? __pfx_qdisc_graft (net/sched/sch_api.c:1091)
[ 238.030095][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[ 238.030102][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[ 238.030106][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[ 238.030114][ T318] tc_get_qdisc (net/sched/sch_api.c:1529 net/sched/sch_api.c:1556)
...
[ 238.072958][ T318] Allocated by task 303 on cpu 5 at 238.026275s:
[ 238.073392][ T318] kasan_save_stack (mm/kasan/common.c:58)
[ 238.073884][ T318] kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5))
[ 238.074230][ T318] __kasan_slab_alloc (mm/kasan/common.c:369)
[ 238.074578][ T318] kmem_cache_alloc_node_noprof (./include/linux/kasan.h:253 mm/slub.c:4542 mm/slub.c:4869 mm/slub.c:4921)
[ 238.076091][ T318] kmalloc_reserve (net/core/skbuff.c:616 (discriminator 107))
[ 238.076450][ T318] __alloc_skb (net/core/skbuff.c:713)
[ 238.076834][ T318] alloc_skb_with_frags (./include/linux/skbuff.h:1383 net/core/skbuff.c:6763)
[ 238.077178][ T318] sock_alloc_send_pskb (net/core/sock.c:2997)
[ 238.077520][ T318] packet_sendmsg (net/packet/af_packet.c:2926 net/packet/af_packet.c:3019 net/packet/af_packet.c:3108)
[ 238.081469][ T318]
[ 238.081870][ T318] Freed by task 299 on cpu 1 at 238.028496s:
[ 238.082761][ T318] kasan_save_stack (mm/kasan/common.c:58)
[ 238.083481][ T318] kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5))
[ 238.085348][ T318] kasan_save_free_info (mm/kasan/generic.c:587 (discriminator 1))
[ 238.085900][ T318] __kasan_slab_free (mm/kasan/common.c:287)
[ 238.086439][ T318] kmem_cache_free (mm/slub.c:6168 (discriminator 3) mm/slub.c:6298 (discriminator 3))
[ 238.087007][ T318] skb_release_data (net/core/skbuff.c:1139)
[ 238.087491][ T318] consume_skb (net/core/skbuff.c:1451)
[ 238.087757][ T318] teql_master_xmit (net/sched/sch_teql.c:358)
[ 238.088116][ T318] dev_hard_start_xmit (./include/linux/netdevice.h:5324 ./include/linux/netdevice.h:5333 net/core/dev.c:3871 net/core/dev.c:3887)
[ 238.088468][ T318] sch_direct_xmit (net/sched/sch_generic.c:347)
[ 238.088820][ T318] __qdisc_run (net/sched/sch_generic.c:420 (discriminator 1))
[ 238.089166][ T318] __dev_queue_xmit (./include/net/sch_generic.h:229 ./include/net/pkt_sched.h:121 ./include/net/pkt_sched.h:117 net/core/dev.c:4196 net/core/dev.c:4802)
Workflow to reproduce:
1. Initialize a TEQL topology (dummy0 and ifb0 as slaves, teql0 up).
2. Start multiple sender workers continuously transmitting packets
through teql0 to drive teql_master_xmit().
3. In parallel, repeatedly delete and re-add the root qdisc on
dummy0 and ifb0 via RTNETLINK, forcing frequent teardown and reset activity
(teql_destroy() / qdisc_reset()).
4. After running both workloads concurrently for several iterations,
KASAN reports slab-use-after-free or double-free in the skb free path.
Fix this by moving dev_reset_queue to sch_generic.h and calling it, instead
of qdisc_reset, in teql_destroy since it handles both the lock and lockless
cases correctly for root qdiscs.
Fixes: 96009c7d500e ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock")
Reported-by: Xianrui Dong <keenanat2000@gmail.com>
Tested-by: Xianrui Dong <keenanat2000@gmail.com>
Co-developed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260315155422.147256-1-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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rtnl_kfree_skbs() reduces RTNL and qdisc spinlock hold time.
skbs are freed later after RTNL has been released.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260306133154.678730-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Following typical script is extremely disruptive,
because each graft operation calls dev_deactivate()
which resets all the queues of the device.
QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
tc qd del dev $ETH root 2>/dev/null
tc qd add dev $ETH root handle 1: mq
for i in `seq 1 $TXQS`
do
slot=$( printf %x $(( i )) )
tc qd add dev $ETH parent 1:$slot fq $QPARAM
done
done
One can add "ip link set dev $ETH down/up" to reduce the disruption time:
QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
ip link set dev $ETH down
tc qd del dev $ETH root 2>/dev/null
tc qd add dev $ETH root handle 1: mq
for i in `seq 1 $TXQS`
do
slot=$( printf %x $(( i )) )
tc qd add dev $ETH parent 1:$slot fq $QPARAM
done
ip link set dev $ETH up
done
Or we can add a @reset_needed flag to dev_deactivate() and
dev_deactivate_many().
This flag is set to true at device dismantle or linkwatch_do_dev(),
and to false for graft operations.
In the future, we might only stop one queue instead of the whole
device, ie call dev_deactivate_queue() instead of dev_deactivate().
I think the problem (quadratic behavior) was added in commit
2fb541c862c9 ("net: sch_generic: aviod concurrent reset and enqueue op
for lockless qdisc") but this does not look serious enough to deserve
risky backports.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20260307163430.470644-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Create new enum qdisc_drop_reason and trace_qdisc_drop tracepoint
for qdisc layer drop diagnostics with direct qdisc context visibility.
The new tracepoint includes qdisc handle, parent, kind (name), and
device information. Existing SKB_DROP_REASON_QDISC_DROP is retained
for backwards compatibility via kfree_skb_reason().
Convert qdiscs with drop reasons to use the new infrastructure.
Change CAKE's cobalt_should_drop() return type from enum skb_drop_reason
to enum qdisc_drop_reason to fix implicit enum conversion warnings.
Use QDISC_DROP_UNSPEC as the 'not dropped' sentinel instead of
SKB_NOT_DROPPED_YET. Both have the same compiled value (0), so the
comparison logic remains semantically equivalent.
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/177211345275.3011628.1974310302645218067.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Currently we are registering one dynamic lockdep key for each allocated
qdisc, to avoid false deadlock reports when mirred (or TC eBPF) redirects
packets to another device while the root lock is acquired [1].
Since dynamic keys are a limited resource, we can save them at least for
qdiscs that are not meant to acquire the root lock in the traffic path,
or to carry traffic at all, like:
- clsact
- ingress
- noqueue
Don't register dynamic keys for the above schedulers, so that we hit
MAX_LOCKDEP_KEYS later in our tests.
[1] https://github.com/multipath-tcp/mptcp_net-next/issues/451
Changes in v2:
- change ordering of spin_lock_init() vs. lockdep_register_key()
(Jakub Kicinski)
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://patch.msgid.link/94448f7fa7c4f52d2ce416a4895ec87d456d7417.1770220576.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR (net-6.18-rc6).
No conflicts, adjacent changes in:
drivers/net/phy/micrel.c
96a9178a29a6 ("net: phy: micrel: lan8814 fix reset of the QSGMII interface")
61b7ade9ba8c ("net: phy: micrel: Add support for non PTP SKUs for lan8814")
and a trivial one in tools/testing/selftests/drivers/net/Makefile.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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After commit 100dfa74cad9 ("inet: dev_queue_xmit() llist adoption")
I started seeing many qdisc requeues on IDPF under high TX workload.
$ tc -s qd sh dev eth1 handle 1: ; sleep 1; tc -s qd sh dev eth1 handle 1:
qdisc mq 1: root
Sent 43534617319319 bytes 268186451819 pkt (dropped 0, overlimits 0 requeues 3532840114)
backlog 1056Kb 6675p requeues 3532840114
qdisc mq 1: root
Sent 43554665866695 bytes 268309964788 pkt (dropped 0, overlimits 0 requeues 3537737653)
backlog 781164b 4822p requeues 3537737653
This is caused by try_bulk_dequeue_skb() being only limited by BQL budget.
perf record -C120-239 -e qdisc:qdisc_dequeue sleep 1 ; perf script
...
netperf 75332 [146] 2711.138269: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1292 skbaddr=0xff378005a1e9f200
netperf 75332 [146] 2711.138953: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1213 skbaddr=0xff378004d607a500
netperf 75330 [144] 2711.139631: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1233 skbaddr=0xff3780046be20100
netperf 75333 [147] 2711.140356: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1093 skbaddr=0xff37800514845b00
netperf 75337 [151] 2711.141037: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1353 skbaddr=0xff37800460753300
netperf 75337 [151] 2711.141877: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1367 skbaddr=0xff378004e72c7b00
netperf 75330 [144] 2711.142643: qdisc:qdisc_dequeue: dequeue ifindex=5 qdisc handle=0x80150000 parent=0x10013 txq_state=0x0 packets=1202 skbaddr=0xff3780045bd60000
...
This is bad because :
1) Large batches hold one victim cpu for a very long time.
2) Driver often hit their own TX ring limit (all slots are used).
3) We call dev_requeue_skb()
4) Requeues are using a FIFO (q->gso_skb), breaking qdisc ability to
implement FQ or priority scheduling.
5) dequeue_skb() gets packets from q->gso_skb one skb at a time
with no xmit_more support. This is causing many spinlock games
between the qdisc and the device driver.
Requeues were supposed to be very rare, lets keep them this way.
Limit batch sizes to /proc/sys/net/core/dev_weight (default 64) as
__qdisc_run() was designed to use.
Fixes: 5772e9a3463b ("qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://patch.msgid.link/20251109161215.2574081-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Remove busylock spinlock and use a lockless list (llist)
to reduce spinlock contention to the minimum.
Idea is that only one cpu might spin on the qdisc spinlock,
while others simply add their skb in the llist.
After this patch, we get a 300 % improvement on heavy TX workloads.
- Sending twice the number of packets per second.
- While consuming 50 % less cycles.
Note that this also allows in the future to submit batches
to various qdisc->enqueue() methods.
Tested:
- Dual Intel(R) Xeon(R) 6985P-C (480 hyper threads).
- 100Gbit NIC, 30 TX queues with FQ packet scheduler.
- echo 64 >/sys/kernel/slab/skbuff_small_head/cpu_partial (avoid contention in mm)
- 240 concurrent "netperf -t UDP_STREAM -- -m 120 -n"
Before:
16 Mpps (41 Mpps if each thread is pinned to a different cpu)
vmstat 2 5
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
243 0 0 2368988672 51036 1100852 0 0 146 1 242 60 0 9 91 0 0
244 0 0 2368988672 51036 1100852 0 0 536 10 487745 14718 0 52 48 0 0
244 0 0 2368988672 51036 1100852 0 0 512 0 503067 46033 0 52 48 0 0
244 0 0 2368988672 51036 1100852 0 0 512 0 494807 12107 0 52 48 0 0
244 0 0 2368988672 51036 1100852 0 0 702 26 492845 10110 0 52 48 0 0
Lock contention (1 second sample taken on 8 cores)
perf lock record -C0-7 sleep 1; perf lock contention
contended total wait max wait avg wait type caller
442111 6.79 s 162.47 ms 15.35 us spinlock dev_hard_start_xmit+0xcd
5961 9.57 ms 8.12 us 1.60 us spinlock __dev_queue_xmit+0x3a0
244 560.63 us 7.63 us 2.30 us spinlock do_softirq+0x5b
13 25.09 us 3.21 us 1.93 us spinlock net_tx_action+0xf8
If netperf threads are pinned, spinlock stress is very high.
perf lock record -C0-7 sleep 1; perf lock contention
contended total wait max wait avg wait type caller
964508 7.10 s 147.25 ms 7.36 us spinlock dev_hard_start_xmit+0xcd
201 268.05 us 4.65 us 1.33 us spinlock __dev_queue_xmit+0x3a0
12 26.05 us 3.84 us 2.17 us spinlock do_softirq+0x5b
@__dev_queue_xmit_ns:
[256, 512) 21 | |
[512, 1K) 631 | |
[1K, 2K) 27328 |@ |
[2K, 4K) 265392 |@@@@@@@@@@@@@@@@ |
[4K, 8K) 417543 |@@@@@@@@@@@@@@@@@@@@@@@@@@ |
[8K, 16K) 826292 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[16K, 32K) 733822 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ |
[32K, 64K) 19055 |@ |
[64K, 128K) 17240 |@ |
[128K, 256K) 25633 |@ |
[256K, 512K) 4 | |
After:
29 Mpps (57 Mpps if each thread is pinned to a different cpu)
vmstat 2 5
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
78 0 0 2369573632 32896 1350988 0 0 22 0 331 254 0 8 92 0 0
75 0 0 2369573632 32896 1350988 0 0 22 50 425713 280199 0 23 76 0 0
104 0 0 2369573632 32896 1350988 0 0 290 0 430238 298247 0 23 76 0 0
86 0 0 2369573632 32896 1350988 0 0 132 0 428019 291865 0 24 76 0 0
90 0 0 2369573632 32896 1350988 0 0 502 0 422498 278672 0 23 76 0 0
perf lock record -C0-7 sleep 1; perf lock contention
contended total wait max wait avg wait type caller
2524 116.15 ms 486.61 us 46.02 us spinlock __dev_queue_xmit+0x55b
5821 107.18 ms 371.67 us 18.41 us spinlock dev_hard_start_xmit+0xcd
2377 9.73 ms 35.86 us 4.09 us spinlock ___slab_alloc+0x4e0
923 5.74 ms 20.91 us 6.22 us spinlock ___slab_alloc+0x5c9
121 3.42 ms 193.05 us 28.24 us spinlock net_tx_action+0xf8
6 564.33 us 167.60 us 94.05 us spinlock do_softirq+0x5b
If netperf threads are pinned (~54 Mpps)
perf lock record -C0-7 sleep 1; perf lock contention
32907 316.98 ms 195.98 us 9.63 us spinlock dev_hard_start_xmit+0xcd
4507 61.83 ms 212.73 us 13.72 us spinlock __dev_queue_xmit+0x554
2781 23.53 ms 40.03 us 8.46 us spinlock ___slab_alloc+0x5c9
3554 18.94 ms 34.69 us 5.33 us spinlock ___slab_alloc+0x4e0
233 9.09 ms 215.70 us 38.99 us spinlock do_softirq+0x5b
153 930.66 us 48.67 us 6.08 us spinlock net_tx_action+0xfd
84 331.10 us 14.22 us 3.94 us spinlock ___slab_alloc+0x5c9
140 323.71 us 9.94 us 2.31 us spinlock ___slab_alloc+0x4e0
@__dev_queue_xmit_ns:
[128, 256) 1539830 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ |
[256, 512) 2299558 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[512, 1K) 483936 |@@@@@@@@@@ |
[1K, 2K) 265345 |@@@@@@ |
[2K, 4K) 145463 |@@@ |
[4K, 8K) 54571 |@ |
[8K, 16K) 10270 | |
[16K, 32K) 9385 | |
[32K, 64K) 7749 | |
[64K, 128K) 26799 | |
[128K, 256K) 2665 | |
[256K, 512K) 665 | |
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251014171907.3554413-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
This reverts commits 0f022d32c3eca477fbf79a205243a6123ed0fe11
and 44180feaccf266d9b0b28cc4ceaac019817deb5c.
Prior patch in this series implemented loop detection
in act_mirred, we can remove q->owner to save some cycles
in the fast path.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251014171907.3554413-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Currently, packets dropped by pfifo_fast due to queue overflow are
marked with a generic SKB_DROP_REASON_QDISC_DROP in __dev_xmit_skb().
This patch adds explicit drop reason SKB_DROP_REASON_QDISC_OVERLIMIT
for queue-full cases, providing better distinction from other qdisc drops.
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://patch.msgid.link/20250724212837119BP9HOs0ibXDRWgsXMMir7@zte.com.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Move this API to the canonical timer_*() namespace.
[ tglx: Redone against pre rc1 ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
|
|
Use bpf_try_module_get()/bpf_module_put() instead of try_module_get()/
module_put() when handling default qdisc since users can assign a bpf
qdisc to it.
To trigger the bug:
$ bpftool struct_ops register bpf_qdisc_fq.bpf.o /sys/fs/bpf
$ echo bpf_fq > /proc/sys/net/core/default_qdisc
Fixes: c8240344956e ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250429192128.3860571-1-ameryhung@gmail.com
|
|
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Martin KaFai Lau says:
====================
pull-request: bpf-next 2025-04-17
We've added 12 non-merge commits during the last 9 day(s) which contain
a total of 18 files changed, 1748 insertions(+), 19 deletions(-).
The main changes are:
1) bpf qdisc support, from Amery Hung.
A qdisc can be implemented in bpf struct_ops programs and
can be used the same as other existing qdiscs in the
"tc qdisc" command.
2) Add xsk tail adjustment tests, from Tushar Vyavahare.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
selftests/bpf: Test attaching bpf qdisc to mq and non root
selftests/bpf: Add a bpf fq qdisc to selftest
selftests/bpf: Add a basic fifo qdisc test
libbpf: Support creating and destroying qdisc
bpf: net_sched: Disable attaching bpf qdisc to non root
bpf: net_sched: Support updating bstats
bpf: net_sched: Add a qdisc watchdog timer
bpf: net_sched: Add basic bpf qdisc kfuncs
bpf: net_sched: Support implementation of Qdisc_ops in bpf
bpf: Prepare to reuse get_ctx_arg_idx
selftests/xsk: Add tail adjustment tests and support check
selftests/xsk: Add packet stream replacement function
====================
Link: https://patch.msgid.link/20250417184338.3152168-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
The recent advancement in bpf such as allocated objects, bpf list and bpf
rbtree has provided powerful and flexible building blocks to realize
sophisticated packet scheduling algorithms. As struct_ops now supports
core operators in Qdisc_ops, start allowing qdisc to be implemented using
bpf struct_ops with this patch. Users can implement Qdisc_ops.{enqueue,
dequeue, init, reset, destroy} in bpf and register the qdisc dynamically
into the kernel.
Co-developed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409214606.2000194-3-ameryhung@gmail.com
|
|
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
dev_deactivate_many() role is to remove the qdiscs
of a network device.
When/if a qdisc is dismantled, an rcu grace period
is needed to make sure all outstanding qdisc enqueue
are done before we proceed with a qdisc reset.
Most virtual devices do not have a qdisc.
We can call the expensive synchronize_net() only
if needed.
Note that dev_deactivate_many() does not have to deal
with qdisc-less dev_queue_xmit, as an old comment
was claiming.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250109171850.2871194-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
In commit d7811e623dd4 ("[NET]: Drop tx lock in dev_watchdog_up")
dev_watchdog_up() became a simple wrapper for __netdev_watchdog_up()
Herbert also said : "In 2.6.19 we can eliminate the unnecessary
__dev_watchdog_up and replace it with dev_watchdog_up."
This patch consolidates things to have only two functions, with
a common prefix.
- netdev_watchdog_up(), exported for the sake of one freescale driver.
This replaces __netdev_watchdog_up() and dev_watchdog_up().
- netdev_watchdog_down(), static to net/sched/sch_generic.c
This replaces dev_watchdog_down().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20250105090924.1661822-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Jakub added a lockdep_assert_no_hardirq() check in __page_pool_put_page()
to increase test coverage.
syzbot found a splat caused by hard irq blocking in
ptr_ring_resize_multiple() [1]
As current users of ptr_ring_resize_multiple() do not require
hard irqs being masked, replace it to only block BH.
Rename helpers to better reflect they are safe against BH only.
- ptr_ring_resize_multiple() to ptr_ring_resize_multiple_bh()
- skb_array_resize_multiple() to skb_array_resize_multiple_bh()
[1]
WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 __page_pool_put_page net/core/page_pool.c:709 [inline]
WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780
Modules linked in:
CPU: 1 UID: 0 PID: 9150 Comm: syz.1.1052 Not tainted 6.11.0-rc3-syzkaller-00202-gf8669d7b5f5d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:__page_pool_put_page net/core/page_pool.c:709 [inline]
RIP: 0010:page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780
Code: 74 0e e8 7c aa fb f7 eb 43 e8 75 aa fb f7 eb 3c 65 8b 1d 38 a8 6a 76 31 ff 89 de e8 a3 ae fb f7 85 db 74 0b e8 5a aa fb f7 90 <0f> 0b 90 eb 1d 65 8b 1d 15 a8 6a 76 31 ff 89 de e8 84 ae fb f7 85
RSP: 0018:ffffc9000bda6b58 EFLAGS: 00010083
RAX: ffffffff8997e523 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc9000fbd0000 RSI: 0000000000001842 RDI: 0000000000001843
RBP: 0000000000000000 R08: ffffffff8997df2c R09: 1ffffd40003a000d
R10: dffffc0000000000 R11: fffff940003a000e R12: ffffea0001d00040
R13: ffff88802e8a4000 R14: dffffc0000000000 R15: 00000000ffffffff
FS: 00007fb7aaf716c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa15a0d4b72 CR3: 00000000561b0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tun_ptr_free drivers/net/tun.c:617 [inline]
__ptr_ring_swap_queue include/linux/ptr_ring.h:571 [inline]
ptr_ring_resize_multiple_noprof include/linux/ptr_ring.h:643 [inline]
tun_queue_resize drivers/net/tun.c:3694 [inline]
tun_device_event+0xaaf/0x1080 drivers/net/tun.c:3714
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2032 [inline]
call_netdevice_notifiers net/core/dev.c:2046 [inline]
dev_change_tx_queue_len+0x158/0x2a0 net/core/dev.c:9024
do_setlink+0xff6/0x41f0 net/core/rtnetlink.c:2923
rtnl_setlink+0x40d/0x5a0 net/core/rtnetlink.c:3201
rtnetlink_rcv_msg+0x73f/0xcf0 net/core/rtnetlink.c:6647
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
Fixes: ff4e538c8c3e ("page_pool: add a lockdep check for recycling in hardirq")
Reported-by: syzbot+f56a5c5eac2b28439810@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/671e10df.050a0220.2b8c0f.01cf.GAE@google.com/T/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241217135121.326370-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Some workloads hit the infamous dev_watchdog() message:
"NETDEV WATCHDOG: eth0 (xxxx): transmit queue XX timed out"
It seems possible to hit this even for perfectly normal
BQL enabled drivers:
1) Assume a TX queue was idle for more than dev->watchdog_timeo
(5 seconds unless changed by the driver)
2) Assume a big packet is sent, exceeding current BQL limit.
3) Driver ndo_start_xmit() puts the packet in TX ring,
and netdev_tx_sent_queue() is called.
4) QUEUE_STATE_STACK_XOFF could be set from netdev_tx_sent_queue()
before txq->trans_start has been written.
5) txq->trans_start is written later, from netdev_start_xmit()
if (rc == NETDEV_TX_OK)
txq_trans_update(txq)
dev_watchdog() running on another cpu could read the old
txq->trans_start, and then see QUEUE_STATE_STACK_XOFF, because 5)
did not happen yet.
To solve the issue, write txq->trans_start right before one XOFF bit
is set :
- _QUEUE_STATE_DRV_XOFF from netif_tx_stop_queue()
- __QUEUE_STATE_STACK_XOFF from netdev_tx_sent_queue()
From dev_watchdog(), we have to read txq->state before txq->trans_start.
Add memory barriers to enforce correct ordering.
In the future, we could avoid writing over txq->trans_start for normal
operations, and rename this field to txq->xoff_start_time.
Fixes: bec251bc8b6a ("net: no longer stop all TX queues in dev_watchdog()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20241015194118.3951657-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
Cross-merge networking fixes after downstream PR.
No conflicts, no adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
When the noop_qdisc owner isn't initialized, then it will be 0,
so packets will erroneously be regarded as having been subject
to recursion as long as only CPU 0 queues them. For non-SMP,
that's all packets, of course. This causes a change in what's
reported to userspace, normally noop_qdisc would drop packets
silently, but with this change the syscall returns -ENOBUFS if
RECVERR is also set on the socket.
Fix this by initializing the owner field to -1, just like it
would be for dynamically allocated qdiscs by qdisc_alloc().
Fixes: 0f022d32c3ec ("net/sched: Fix mirred deadlock on device recursion")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240607175340.786bfb938803.I493bf8422e36be4454c08880a8d3703cea8e421a@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Catching and debugging missing qdiscs is pretty tricky. When qdisc
is deleted we replace it with a noop qdisc, which silently drops
all the packets. Since the noop qdisc has a single static instance
we can't count drops at the qdisc level. Count them as dev->tx_drops.
ip netns add red
ip link add type veth peer netns red
ip link set dev veth0 up
ip -netns red link set dev veth0 up
ip a a dev veth0 10.0.0.1/24
ip -netns red a a dev veth0 10.0.0.2/24
ping -c 2 10.0.0.2
# 2 packets transmitted, 2 received, 0% packet loss, time 1031ms
ip -s link show dev veth0
# TX: bytes packets errors dropped carrier collsns
# 1314 17 0 0 0 0
tc qdisc replace dev veth0 root handle 1234: mq
tc qdisc replace dev veth0 parent 1234:1 pfifo
tc qdisc del dev veth0 parent 1234:1
ping -c 2 10.0.0.2
# 2 packets transmitted, 0 received, 100% packet loss, time 1034ms
ip -s link show dev veth0
# TX: bytes packets errors dropped carrier collsns
# 1314 17 0 3 0 0
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20240529162527.3688979-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
Applications are sensitive to long network latency, particularly
heartbeat monitoring ones. Longer the tx timeout recovery higher the
risk with such applications on a production machines. This patch
remedies, yet honoring device set tx timeout.
Modify watchdog next timeout to be shorter than the device specified.
Compute the next timeout be equal to device watchdog timeout less the
how long ago queue stop had been done. At next watchdog timeout tx
timeout handler is called into if still in stopped state. Either called
or not called, restore the watchdog timeout back to device specified.
Signed-off-by: Praveen Kumar Kannoju <praveen.kannoju@oracle.com>
Link: https://lore.kernel.org/r/20240508133617.4424-1-praveen.kannoju@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Naresh and Eric report several errors (corrupted elements in the dynamic
key hash list), when running tdc.py or syzbot. The error path of
qdisc_alloc() and qdisc_create() frees the qdisc memory, but it forgets
to unregister the lockdep key, thus causing use-after-free like the
following one:
==================================================================
BUG: KASAN: slab-use-after-free in lockdep_register_key+0x5f2/0x700
Read of size 8 at addr ffff88811236f2a8 by task ip/7925
CPU: 26 PID: 7925 Comm: ip Kdump: loaded Not tainted 6.9.0-rc2+ #648
Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0 07/26/2013
Call Trace:
<TASK>
dump_stack_lvl+0x7c/0xc0
print_report+0xc9/0x610
kasan_report+0x89/0xc0
lockdep_register_key+0x5f2/0x700
qdisc_alloc+0x21d/0xb60
qdisc_create_dflt+0x63/0x3c0
attach_one_default_qdisc.constprop.37+0x8e/0x170
dev_activate+0x4bd/0xc30
__dev_open+0x275/0x380
__dev_change_flags+0x3f1/0x570
dev_change_flags+0x7c/0x160
do_setlink+0x1ea1/0x34b0
__rtnl_newlink+0x8c9/0x1510
rtnl_newlink+0x61/0x90
rtnetlink_rcv_msg+0x2f0/0xbc0
netlink_rcv_skb+0x120/0x380
netlink_unicast+0x420/0x630
netlink_sendmsg+0x732/0xbc0
__sock_sendmsg+0x1ea/0x280
____sys_sendmsg+0x5a9/0x990
___sys_sendmsg+0xf1/0x180
__sys_sendmsg+0xd3/0x180
do_syscall_64+0x96/0x180
entry_SYSCALL_64_after_hwframe+0x71/0x79
RIP: 0033:0x7f9503f4fa07
Code: 0a 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
RSP: 002b:00007fff6c729068 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000006630c681 RCX: 00007f9503f4fa07
RDX: 0000000000000000 RSI: 00007fff6c7290d0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000078
R10: 000000000000009b R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff6c729180 R14: 0000000000000000 R15: 000055bf67dd9040
</TASK>
Allocated by task 7745:
kasan_save_stack+0x1c/0x40
kasan_save_track+0x10/0x30
__kasan_kmalloc+0x7b/0x90
__kmalloc_node+0x1ff/0x460
qdisc_alloc+0xae/0xb60
qdisc_create+0xdd/0xfb0
tc_modify_qdisc+0x37e/0x1960
rtnetlink_rcv_msg+0x2f0/0xbc0
netlink_rcv_skb+0x120/0x380
netlink_unicast+0x420/0x630
netlink_sendmsg+0x732/0xbc0
__sock_sendmsg+0x1ea/0x280
____sys_sendmsg+0x5a9/0x990
___sys_sendmsg+0xf1/0x180
__sys_sendmsg+0xd3/0x180
do_syscall_64+0x96/0x180
entry_SYSCALL_64_after_hwframe+0x71/0x79
Freed by task 7745:
kasan_save_stack+0x1c/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x36/0x60
__kasan_slab_free+0xfe/0x180
kfree+0x113/0x380
qdisc_create+0xafb/0xfb0
tc_modify_qdisc+0x37e/0x1960
rtnetlink_rcv_msg+0x2f0/0xbc0
netlink_rcv_skb+0x120/0x380
netlink_unicast+0x420/0x630
netlink_sendmsg+0x732/0xbc0
__sock_sendmsg+0x1ea/0x280
____sys_sendmsg+0x5a9/0x990
___sys_sendmsg+0xf1/0x180
__sys_sendmsg+0xd3/0x180
do_syscall_64+0x96/0x180
entry_SYSCALL_64_after_hwframe+0x71/0x79
Fix this ensuring that lockdep_unregister_key() is called before the
qdisc struct is freed, also in the error path of qdisc_create() and
qdisc_alloc().
Fixes: af0cb3fa3f9e ("net/sched: fix false lockdep warning on qdisc root lock")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/netdev/20240429221706.1492418-1-naresh.kamboju@linaro.org/
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/2aa1ca0c0a3aa0acc15925c666c777a4b5de553c.1714496886.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Xiumei and Christoph reported the following lockdep splat, complaining of
the qdisc root lock being taken twice:
============================================
WARNING: possible recursive locking detected
6.7.0-rc3+ #598 Not tainted
--------------------------------------------
swapper/2/0 is trying to acquire lock:
ffff888177190110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70
but task is already holding lock:
ffff88811995a110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&sch->q.lock);
lock(&sch->q.lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
5 locks held by swapper/2/0:
#0: ffff888135a09d98 ((&in_dev->mr_ifc_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11a/0x510
#1: ffffffffaaee5260 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x2c0/0x1ed0
#2: ffffffffaaee5200 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x209/0x2e70
#3: ffff88811995a110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70
#4: ffffffffaaee5200 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x209/0x2e70
stack backtrace:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.7.0-rc3+ #598
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7353+9de0a3cc 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0x4a/0x80
__lock_acquire+0xfdd/0x3150
lock_acquire+0x1ca/0x540
_raw_spin_lock+0x34/0x80
__dev_queue_xmit+0x1560/0x2e70
tcf_mirred_act+0x82e/0x1260 [act_mirred]
tcf_action_exec+0x161/0x480
tcf_classify+0x689/0x1170
prio_enqueue+0x316/0x660 [sch_prio]
dev_qdisc_enqueue+0x46/0x220
__dev_queue_xmit+0x1615/0x2e70
ip_finish_output2+0x1218/0x1ed0
__ip_finish_output+0x8b3/0x1350
ip_output+0x163/0x4e0
igmp_ifc_timer_expire+0x44b/0x930
call_timer_fn+0x1a2/0x510
run_timer_softirq+0x54d/0x11a0
__do_softirq+0x1b3/0x88f
irq_exit_rcu+0x18f/0x1e0
sysvec_apic_timer_interrupt+0x6f/0x90
</IRQ>
This happens when TC does a mirred egress redirect from the root qdisc of
device A to the root qdisc of device B. As long as these two locks aren't
protecting the same qdisc, they can be acquired in chain: add a per-qdisc
lockdep key to silence false warnings.
This dynamic key should safely replace the static key we have in sch_htb:
it was added to allow enqueueing to the device "direct qdisc" while still
holding the qdisc root lock.
v2: don't use static keys anymore in HTB direct qdiscs (thanks Eric Dumazet)
CC: Maxim Mikityanskiy <maxim@isovalent.com>
CC: Xiumei Mu <xmu@redhat.com>
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/451
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://lore.kernel.org/r/7dc06d6158f72053cf877a82e2a7a5bd23692faa.1713448007.git.dcaratti@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
When the mirred action is used on a classful egress qdisc and a packet is
mirrored or redirected to self we hit a qdisc lock deadlock.
See trace below.
[..... other info removed for brevity....]
[ 82.890906]
[ 82.890906] ============================================
[ 82.890906] WARNING: possible recursive locking detected
[ 82.890906] 6.8.0-05205-g77fadd89fe2d-dirty #213 Tainted: G W
[ 82.890906] --------------------------------------------
[ 82.890906] ping/418 is trying to acquire lock:
[ 82.890906] ffff888006994110 (&sch->q.lock){+.-.}-{3:3}, at:
__dev_queue_xmit+0x1778/0x3550
[ 82.890906]
[ 82.890906] but task is already holding lock:
[ 82.890906] ffff888006994110 (&sch->q.lock){+.-.}-{3:3}, at:
__dev_queue_xmit+0x1778/0x3550
[ 82.890906]
[ 82.890906] other info that might help us debug this:
[ 82.890906] Possible unsafe locking scenario:
[ 82.890906]
[ 82.890906] CPU0
[ 82.890906] ----
[ 82.890906] lock(&sch->q.lock);
[ 82.890906] lock(&sch->q.lock);
[ 82.890906]
[ 82.890906] *** DEADLOCK ***
[ 82.890906]
[..... other info removed for brevity....]
Example setup (eth0->eth0) to recreate
tc qdisc add dev eth0 root handle 1: htb default 30
tc filter add dev eth0 handle 1: protocol ip prio 2 matchall \
action mirred egress redirect dev eth0
Another example(eth0->eth1->eth0) to recreate
tc qdisc add dev eth0 root handle 1: htb default 30
tc filter add dev eth0 handle 1: protocol ip prio 2 matchall \
action mirred egress redirect dev eth1
tc qdisc add dev eth1 root handle 1: htb default 30
tc filter add dev eth1 handle 1: protocol ip prio 2 matchall \
action mirred egress redirect dev eth0
We fix this by adding an owner field (CPU id) to struct Qdisc set after
root qdisc is entered. When the softirq enters it a second time, if the
qdisc owner is the same CPU, the packet is dropped to break the loop.
Reported-by: Mingshuai Ren <renmingshuai@huawei.com>
Closes: https://lore.kernel.org/netdev/20240314111713.5979-1-renmingshuai@huawei.com/
Fixes: 3bcb846ca4cf ("net: get rid of spin_trylock() in net_tx_action()")
Fixes: e578d9c02587 ("net: sched: use counter to break reclassify loops")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20240415210728.36949-1-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
dev_tx_weight is used in tx fast path.
Move it to net_hotdata for better cache locality.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240306160031.874438-9-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Inserting the device to block xarray in qdisc_create() is not suitable
place to do this. As it requires use of tcf_block() callback, it causes
multiple issues. It is called for all qdisc types, which is incorrect.
So, instead, move it to more suitable place, which is tcf_block_get_ext()
and make sure it is only done for qdiscs that use block infrastructure
and also only for blocks which are shared.
Symmetrically, alter the cleanup path, move the xarray entry removal
into tcf_block_put_ext().
Fixes: 913b47d3424e ("net/sched: Introduce tc block netdev tracking infra")
Reported-by: Ido Schimmel <idosch@nvidia.com>
Closes: https://lore.kernel.org/all/ZY1hBb8GFwycfgvd@shredder/
Reported-by: Kui-Feng Lee <sinquersw@gmail.com>
Closes: https://lore.kernel.org/all/ce8d3e55-b8bc-409c-ace9-5cf1c4f7c88e@gmail.com/
Reported-and-tested-by: syzbot+84339b9e7330daae4d66@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/0000000000007c85f5060dcc3a28@google.com/
Reported-and-tested-by: syzbot+806b0572c8d06b66b234@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/00000000000082f2f2060dcc3a92@google.com/
Reported-and-tested-by: syzbot+0039110f932d438130f9@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/0000000000007fbc8c060dcc3a5c@google.com/
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This commit makes tc blocks track which ports have been added to them.
And, with that, we'll be able to use this new information to send
packets to the block's ports. Which will be done in the patch #3 of this
series.
Suggested-by: Jiri Pirko <jiri@nvidia.com>
Co-developed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Co-developed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The top syzbot report for networking (#14 for the entire kernel)
is the queue timeout splat. We kept it around for a long time,
because in real life it provides pretty strong signal that
something is wrong with the driver or the device.
Removing it is also likely to break monitoring for those who
track it as a kernel warning.
Nevertheless, WARN()ings are best suited for catching kernel
programming bugs. If a Tx queue gets starved due to a pause
storm, priority configuration, or other weirdness - that's
obviously a problem, but not a problem we can fix at
the kernel level.
Bite the bullet and convert the WARN() to a print.
Before:
NETDEV WATCHDOG: eni1np1 (netdevsim): transmit queue 0 timed out 1975 ms
WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:525 dev_watchdog+0x39e/0x3b0
[... completely pointless stack trace of a timer follows ...]
Now:
netdevsim netdevsim1 eni1np1: NETDEV WATCHDOG: CPU: 0: transmit queue 0 timed out 1769 ms
Alternatively we could mark the drivers which syzbot has
learned to abuse as "print-instead-of-WARN" selectively.
Reported-by: syzbot+d55372214aff0faa1f1f@syzkaller.appspotmail.com
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
pfifo_fast prio2band[] is renamed to sch_default_prio2band[]
and exported because we want to share it in FQ.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Dave Taht <dave.taht@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
mini_Qdisc_pair::p_miniq is a double pointer to mini_Qdisc, initialized
in ingress_init() to point to net_device::miniq_ingress. ingress Qdiscs
access this per-net_device pointer in mini_qdisc_pair_swap(). Similar
for clsact Qdiscs and miniq_egress.
Unfortunately, after introducing RTNL-unlocked RTM_{NEW,DEL,GET}TFILTER
requests (thanks Hillf Danton for the hint), when replacing ingress or
clsact Qdiscs, for example, the old Qdisc ("@old") could access the same
miniq_{in,e}gress pointer(s) concurrently with the new Qdisc ("@new"),
causing race conditions [1] including a use-after-free bug in
mini_qdisc_pair_swap() reported by syzbot:
BUG: KASAN: slab-use-after-free in mini_qdisc_pair_swap+0x1c2/0x1f0 net/sched/sch_generic.c:1573
Write of size 8 at addr ffff888045b31308 by task syz-executor690/14901
...
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:319
print_report mm/kasan/report.c:430 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:536
mini_qdisc_pair_swap+0x1c2/0x1f0 net/sched/sch_generic.c:1573
tcf_chain_head_change_item net/sched/cls_api.c:495 [inline]
tcf_chain0_head_change.isra.0+0xb9/0x120 net/sched/cls_api.c:509
tcf_chain_tp_insert net/sched/cls_api.c:1826 [inline]
tcf_chain_tp_insert_unique net/sched/cls_api.c:1875 [inline]
tc_new_tfilter+0x1de6/0x2290 net/sched/cls_api.c:2266
...
@old and @new should not affect each other. In other words, @old should
never modify miniq_{in,e}gress after @new, and @new should not update
@old's RCU state.
Fixing without changing sch_api.c turned out to be difficult (please
refer to Closes: for discussions). Instead, make sure @new's first call
always happen after @old's last call (in {ingress,clsact}_destroy()) has
finished:
In qdisc_graft(), return -EBUSY if @old has any ongoing filter requests,
and call qdisc_destroy() for @old before grafting @new.
Introduce qdisc_refcount_dec_if_one() as the counterpart of
qdisc_refcount_inc_nz() used for filter requests. Introduce a
non-static version of qdisc_destroy() that does a TCQ_F_BUILTIN check,
just like qdisc_put() etc.
Depends on patch "net/sched: Refactor qdisc_graft() for ingress and
clsact Qdiscs".
[1] To illustrate, the syzkaller reproducer adds ingress Qdiscs under
TC_H_ROOT (no longer possible after commit c7cfbd115001 ("net/sched:
sch_ingress: Only create under TC_H_INGRESS")) on eth0 that has 8
transmission queues:
Thread 1 creates ingress Qdisc A (containing mini Qdisc a1 and a2),
then adds a flower filter X to A.
Thread 2 creates another ingress Qdisc B (containing mini Qdisc b1 and
b2) to replace A, then adds a flower filter Y to B.
Thread 1 A's refcnt Thread 2
RTM_NEWQDISC (A, RTNL-locked)
qdisc_create(A) 1
qdisc_graft(A) 9
RTM_NEWTFILTER (X, RTNL-unlocked)
__tcf_qdisc_find(A) 10
tcf_chain0_head_change(A)
mini_qdisc_pair_swap(A) (1st)
|
| RTM_NEWQDISC (B, RTNL-locked)
RCU sync 2 qdisc_graft(B)
| 1 notify_and_destroy(A)
|
tcf_block_release(A) 0 RTM_NEWTFILTER (Y, RTNL-unlocked)
qdisc_destroy(A) tcf_chain0_head_change(B)
tcf_chain0_head_change_cb_del(A) mini_qdisc_pair_swap(B) (2nd)
mini_qdisc_pair_swap(A) (3rd) |
... ...
Here, B calls mini_qdisc_pair_swap(), pointing eth0->miniq_ingress to
its mini Qdisc, b1. Then, A calls mini_qdisc_pair_swap() again during
ingress_destroy(), setting eth0->miniq_ingress to NULL, so ingress
packets on eth0 will not find filter Y in sch_handle_ingress().
This is just one of the possible consequences of concurrently accessing
miniq_{in,e}gress pointers.
Fixes: 7a096d579e8e ("net: sched: ingress: set 'unlocked' flag for Qdisc ops")
Fixes: 87f373921c4e ("net: sched: ingress: set 'unlocked' flag for clsact Qdisc ops")
Reported-by: syzbot+b53a9c0d1ea4ad62da8b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/0000000000006cf87705f79acf1a@google.com/
Cc: Hillf Danton <hdanton@sina.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
|
|
syzbot reported a race around qdisc->qdisc_sleeping [1]
It is time we add proper annotations to reads and writes to/from
qdisc->qdisc_sleeping.
[1]
BUG: KCSAN: data-race in dev_graft_qdisc / qdisc_lookup_rcu
read to 0xffff8881286fc618 of 8 bytes by task 6928 on cpu 1:
qdisc_lookup_rcu+0x192/0x2c0 net/sched/sch_api.c:331
__tcf_qdisc_find+0x74/0x3c0 net/sched/cls_api.c:1174
tc_get_tfilter+0x18f/0x990 net/sched/cls_api.c:2547
rtnetlink_rcv_msg+0x7af/0x8c0 net/core/rtnetlink.c:6386
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6413
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x375/0x4c0 net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x1e3/0x270 net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__x64_sys_sendmsg+0x46/0x50 net/socket.c:2593
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
write to 0xffff8881286fc618 of 8 bytes by task 6912 on cpu 0:
dev_graft_qdisc+0x4f/0x80 net/sched/sch_generic.c:1115
qdisc_graft+0x7d0/0xb60 net/sched/sch_api.c:1103
tc_modify_qdisc+0x712/0xf10 net/sched/sch_api.c:1693
rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6395
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6413
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x375/0x4c0 net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x1e3/0x270 net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__x64_sys_sendmsg+0x46/0x50 net/socket.c:2593
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6912 Comm: syz-executor.5 Not tainted 6.4.0-rc3-syzkaller-00190-g0d85b27b0cc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/16/2023
Fixes: 3a7d0d07a386 ("net: sched: extend Qdisc with rcu")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Buslov <vladbu@nvidia.com>
Acked-by: Jamal Hadi Salim<jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The kernel will print several warnings in a short period of time
when it stalls. Like this:
First warning:
[ 7100.097547] ------------[ cut here ]------------
[ 7100.097550] NETDEV WATCHDOG: eno2 (xxx): transmit queue 8 timed out
[ 7100.097571] WARNING: CPU: 8 PID: 0 at net/sched/sch_generic.c:467
dev_watchdog+0x260/0x270
...
Second warning:
[ 7147.756952] rcu: INFO: rcu_preempt self-detected stall on CPU
[ 7147.756958] rcu: 24-....: (59999 ticks this GP) idle=546/1/0x400000000000000
softirq=367 3137/3673146 fqs=13844
[ 7147.756960] (t=60001 jiffies g=4322709 q=133381)
[ 7147.756962] NMI backtrace for cpu 24
...
We calculate that the transmit queue start stall should occur before
7095s according to watchdog_timeo, the rcu start stall at 7087s.
These two times are close together, it is difficult to confirm which
happened first.
To let users know the exact time the stall started, print msecs when
the transmit queue time out.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
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tools/testing/selftests/net/.gitignore
sort the net-next version and use it
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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In attach_default_qdiscs(), if a dev has multiple queues and queue 0 fails
to attach qdisc because there is no memory in attach_one_default_qdisc().
Then dev->qdisc will be noop_qdisc by default. But the other queues may be
able to successfully attach to default qdisc.
In this case, the fallback to noqueue process will be triggered. If the
original attached qdisc is not released and a new one is directly
attached, this will cause netdevice reference leaks.
The following is the bug log:
veth0: default qdisc (fq_codel) fail, fallback to noqueue
unregister_netdevice: waiting for veth0 to become free. Usage count = 32
leaked reference.
qdisc_alloc+0x12e/0x210
qdisc_create_dflt+0x62/0x140
attach_one_default_qdisc.constprop.41+0x44/0x70
dev_activate+0x128/0x290
__dev_open+0x12a/0x190
__dev_change_flags+0x1a2/0x1f0
dev_change_flags+0x23/0x60
do_setlink+0x332/0x1150
__rtnl_newlink+0x52f/0x8e0
rtnl_newlink+0x43/0x70
rtnetlink_rcv_msg+0x140/0x3b0
netlink_rcv_skb+0x50/0x100
netlink_unicast+0x1bb/0x290
netlink_sendmsg+0x37c/0x4e0
sock_sendmsg+0x5f/0x70
____sys_sendmsg+0x208/0x280
Fix this bug by clearing any non-noop qdiscs that may have been assigned
before trying to re-attach.
Fixes: bf6dba76d278 ("net: sched: fallback to qdisc noqueue if default qdisc setup fail")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://lore.kernel.org/r/20220826090055.24424-1-wanghai38@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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The memory allocated by using kzallloc_node and kcalloc has been cleared.
Therefore, the structure members of the new qdisc are 0. So there's no
need to explicitly assign a value of 0.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While reading weight_p, it can be changed concurrently. Thus, we need
to add READ_ONCE() to its reader.
Also, dev_[rt]x_weight can be read/written at the same time. So, we
need to use READ_ONCE() and WRITE_ONCE() for its access. Moreover, to
use the same weight_p while changing dev_[rt]x_weight, we add a mutex
in proc_do_dev_weight().
Fixes: 3d48b53fb2ae ("net: dev_weight: TX/RX orthogonality")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now that the bonding driver keeps track of the last TX time of ARP and
NS probes, we effectively revert the following commits:
32d3e51a82d4 ("net_sched: use macvlan real dev trans_start in dev_trans_start()")
07ce76aa9bcf ("net_sched: make dev_trans_start return vlan's real dev trans_start")
Note that the approach of continuing to hack at this function would not
get us very far, hence the desire to take a different approach. DSA is
also a virtual device that uses NETIF_F_LLTX, but there, many uppers
share the same lower (DSA master, i.e. the physical host port of a
switch). By making dev_trans_start() on a DSA interface return the
dev_trans_start() of the master, we effectively assume that all other
DSA interfaces are silent, otherwise this corrupts the validity of the
probe timestamp data from the bonding driver's perspective.
Furthermore, the hacks didn't take into consideration the fact that the
lower interface of @dev may not have been physical either. For example,
VLAN over VLAN, or DSA with 2 masters in a LAG.
And even furthermore, there are NETIF_F_LLTX devices which are not
stacked, like veth. The hack here would not work with those, because it
would not have to provide the bonding driver something to chew at all.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.
Rename:
dev_hold_track() -> netdev_hold()
dev_put_track() -> netdev_put()
dev_replace_track() -> netdev_ref_replace()
Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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For some unknown reason qdisc_reset() is using
a convoluted way of freeing two lists of skbs.
Use __skb_queue_purge() instead.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20220414011004.2378350-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
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syzbot found a data-race [1] which lead me to add __rcu
annotations to netdev->qdisc, and proper accessors
to get LOCKDEP support.
[1]
BUG: KCSAN: data-race in dev_activate / qdisc_lookup_rcu
write to 0xffff888168ad6410 of 8 bytes by task 13559 on cpu 1:
attach_default_qdiscs net/sched/sch_generic.c:1167 [inline]
dev_activate+0x2ed/0x8f0 net/sched/sch_generic.c:1221
__dev_open+0x2e9/0x3a0 net/core/dev.c:1416
__dev_change_flags+0x167/0x3f0 net/core/dev.c:8139
rtnl_configure_link+0xc2/0x150 net/core/rtnetlink.c:3150
__rtnl_newlink net/core/rtnetlink.c:3489 [inline]
rtnl_newlink+0xf4d/0x13e0 net/core/rtnetlink.c:3529
rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5594
netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2494
rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5612
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x602/0x6d0 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x728/0x850 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg net/socket.c:725 [inline]
____sys_sendmsg+0x39a/0x510 net/socket.c:2413
___sys_sendmsg net/socket.c:2467 [inline]
__sys_sendmsg+0x195/0x230 net/socket.c:2496
__do_sys_sendmsg net/socket.c:2505 [inline]
__se_sys_sendmsg net/socket.c:2503 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2503
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff888168ad6410 of 8 bytes by task 13560 on cpu 0:
qdisc_lookup_rcu+0x30/0x2e0 net/sched/sch_api.c:323
__tcf_qdisc_find+0x74/0x3a0 net/sched/cls_api.c:1050
tc_del_tfilter+0x1c7/0x1350 net/sched/cls_api.c:2211
rtnetlink_rcv_msg+0x5ba/0x7e0 net/core/rtnetlink.c:5585
netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2494
rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5612
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x602/0x6d0 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x728/0x850 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg net/socket.c:725 [inline]
____sys_sendmsg+0x39a/0x510 net/socket.c:2413
___sys_sendmsg net/socket.c:2467 [inline]
__sys_sendmsg+0x195/0x230 net/socket.c:2496
__do_sys_sendmsg net/socket.c:2505 [inline]
__se_sys_sendmsg net/socket.c:2503 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2503
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0xffffffff85dee080 -> 0xffff88815d96ec00
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13560 Comm: syz-executor.2 Not tainted 5.17.0-rc3-syzkaller-00116-gf1baf68e1383-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes: 470502de5bdb ("net: sched: unlock rules update API")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
