From: Kent Overstreet Date: Sun, 31 Mar 2024 21:52:12 +0000 (-0400) Subject: aio: Fix null ptr deref in aio_complete() wakeup X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=caeb4b0a11b3393e43f7fa8e0a5a18462acc66bd;p=users%2Fwilly%2Fpagecache.git aio: Fix null ptr deref in aio_complete() wakeup list_del_init_careful() needs to be the last access to the wait queue entry - it effectively unlocks access. Previously, finish_wait() would see the empty list head and skip taking the lock, and then we'd return - but the completion path would still attempt to do the wakeup after the task_struct pointer had been overwritten. Fixes: 71eb6b6b0ba9 ("fs/aio: obey min_nr when doing wakeups") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-fsdevel/CAHTA-ubfwwB51A5Wg5M6H_rPEQK9pNf8FkAGH=vr=FEkyRrtqw@mail.gmail.com/ Signed-off-by: Kent Overstreet Link: https://lore.kernel.org/stable/20240331215212.522544-1-kent.overstreet%40linux.dev Link: https://lore.kernel.org/r/20240331215212.522544-1-kent.overstreet@linux.dev Signed-off-by: Christian Brauner --- diff --git a/fs/aio.c b/fs/aio.c index 9cdaa2faa5363..0f4f531c97800 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1202,8 +1202,8 @@ static void aio_complete(struct aio_kiocb *iocb) spin_lock_irqsave(&ctx->wait.lock, flags); list_for_each_entry_safe(curr, next, &ctx->wait.head, w.entry) if (avail >= curr->min_nr) { - list_del_init_careful(&curr->w.entry); wake_up_process(curr->w.private); + list_del_init_careful(&curr->w.entry); } spin_unlock_irqrestore(&ctx->wait.lock, flags); }