5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Layton jlayton@kernel.org
[ Upstream commit 1b3ec4f7c03d4b07bad70697d7e2f4088d2cfe92 ]
Light Hsieh reported a KASAN UAF warning in trace_posix_lock_inode(). The request pointer had been changed earlier to point to a lock entry that was added to the inode's list. However, before the tracepoint could fire, another task raced in and freed that lock.
Fix this by moving the tracepoint inside the spinlock, which should ensure that this doesn't happen.
Fixes: 74f6f5912693 ("locks: fix KASAN: use-after-free in trace_event_raw_event_filelock_lock") Link: https://lore.kernel.org/linux-fsdevel/724ffb0a2962e912ea62bb0515deadf39c3251... Reported-by: Light Hsieh (謝明燈) Light.Hsieh@mediatek.com Signed-off-by: Jeff Layton jlayton@kernel.org Link: https://lore.kernel.org/r/20240702-filelock-6-10-v1-1-96e766aadc98@kernel.or... Reviewed-by: Alexander Aring aahringo@redhat.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/locks.c b/fs/locks.c index 90f92784aa554..bafe11deea56b 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1336,9 +1336,9 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, locks_wake_up_blocks(left); } out: + trace_posix_lock_inode(inode, request, error); spin_unlock(&ctx->flc_lock); percpu_up_read(&file_rwsem); - trace_posix_lock_inode(inode, request, error); /* * Free any unused locks. */