From 0c4256196b3a105307e2235fbfd85e768bbcdd0f Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Sun, 30 Aug 2026 23:27:23 +0900 Subject: kprobes: Protect kprobe_blacklist with RCU __within_kprobe_blacklist() traverses kprobe_blacklist without holding kprobe_mutex. When a module is unloaded, kprobe_remove_area_blacklist() removes blacklist entries and immediately frees them with kfree(). A concurrent call to within_kprobe_blacklist() can therefore dereference freed memory. Furthermore, within_kprobe_blacklist() can be called in atomic or non-preemptible contexts where the sleeping kprobe_mutex cannot be taken. Protect kprobe_blacklist with RCU. Use guard(rcu)() and list_for_each_entry_rcu() for traversal, list_add_tail_rcu() for insertions, list_del_rcu() for deletions, and kfree_rcu() to reclaim entries safely after a grace period. Link: https://lore.kernel.org/all/178810004323.64882.16493230858653316962.stgit@devnote2/ Fixes: 376e242429bf ("kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260807155802.F06041F000E9@smtp.kernel.org/ Assisted-by: Antigravity:gemini-3.7-flash Signed-off-by: Masami Hiramatsu (Google) --- include/linux/kprobes.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 8c4f3bb24429..e6de7ae55bda 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -181,6 +181,7 @@ struct kprobe_blacklist_entry { struct list_head list; unsigned long start_addr; unsigned long end_addr; + struct rcu_head rcu; }; #ifdef CONFIG_KPROBES -- cgit