Re: [PATCH v2] fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling

[Christian Brauner]

On Sat, 23 May 2026 21:52:10 +0800, w15303746062@xxxxxxx wrote:
> A SOFTIRQ-safe to SOFTIRQ-unsafe lock order deadlock can occur in
> send_sigio() and send_sigurg() when a process group receives a signal.
> 
> When FASYNC is configured for a process group (PIDTYPE_PGID), both
> functions use read_lock(&tasklist_lock) to traverse the task list.
> However, they are frequently called from softirq context:
> - send_sigio() via input_inject_event -> kill_fasync
> - send_sigurg() via tcp_check_urg -> sk_send_sigurg (NET_RX_SOFTIRQ)
> 
> [...]

Applied to the vfs-7.2.misc branch of the vfs/vfs.git tree.
Patches in the vfs-7.2.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.2.misc

[1/1] fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
      https://git.kernel.org/vfs/vfs/c/00633c468382