diff options
| author | Zack Rusin <zack.rusin@broadcom.com> | 2026-05-05 18:22:31 -0400 |
|---|---|---|
| committer | Zack Rusin <zack.rusin@broadcom.com> | 2026-07-27 11:29:24 -0400 |
| commit | e5c3e484e0d84744a9bd9349469cd41dc8666a2f (patch) | |
| tree | 3504b586cd709056a2f2fab951311aefb953bdab /drivers/gpu | |
| parent | d5ed8749168ad13c0dbaa8300f68d854b6076966 (diff) | |
drm/vmwgfx: skip hash_del_rcu when validation context has no hash table
vmw_validation_add_resource() calls hash_add_rcu() only when
ctx->sw_context is non-NULL, but the doomed-resource error path calls
hash_del_rcu() unconditionally. The validation contexts declared with
DECLARE_VAL_CONTEXT(_, NULL, 0) in vmwgfx_kms.c, vmwgfx_scrn.c,
vmwgfx_stdu.c and vmwgfx_execbuf.c consequently reach a delete for a
node that was never added to any hash chain.
That is harmless today, but only incidentally so. hash_del_rcu() is
hlist_del_init_rcu(), which is guarded by hlist_unhashed(), and
vmw_validation_mem_alloc() hands out memory from __GFP_ZERO pages that
are never recycled within a context's lifetime, so
node->hash.head.pprev is always NULL and the delete does nothing.
Neither property is apparent at the call site, and the asymmetry with
the add side invites a real bug the first time either one changes.
Mirror the condition from the add side so the node is only unlinked
when it was actually linked. No functional change.
Assisted-by: Claude:claude-opus-4.7
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Reviewed-by: Ian Forbes <ian.forbes@broadcom.com>
Link: https://patch.msgid.link/20260505222728.519626-11-zack.rusin@broadcom.com
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/vmwgfx/vmwgfx_validation.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c index 35dc94c3db39..45fde7ec514f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c @@ -309,7 +309,8 @@ int vmw_validation_add_resource(struct vmw_validation_context *ctx, } node->res = vmw_resource_reference_unless_doomed(res); if (!node->res) { - hash_del_rcu(&node->hash.head); + if (ctx->sw_context) + hash_del_rcu(&node->hash.head); return -ESRCH; } |