Subject: CVE-2024-50079: io_uring/sqpoll: ensure task state is TASK_RUNNING when running task_work

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

io_uring/sqpoll: ensure task state is TASK_RUNNING when running task_work

When the sqpoll is exiting and cancels pending work items, it may need
to run task_work. If this happens from within io_uring_cancel_generic(),
then it may be under waiting for the io_uring_task waitqueue. This
results in the below splat from the scheduler, as the ring mutex may be
attempted grabbed while in a TASK_INTERRUPTIBLE state.

Ensure that the task state is set appropriately for that, just like what
is done for the other cases in io_run_task_work().

do not call blocking ops when !TASK_RUNNING; state=1 set at [<0000000029387fd2>] prepare_to_wait+0x88/0x2fc
WARNING: CPU: 6 PID: 59939 at kernel/sched/core.c:8561 __might_sleep+0xf4/0x140
Modules linked in:
CPU: 6 UID: 0 PID: 59939 Comm: iou-sqp-59938 Not tainted 6.12.0-rc3-00113-g8d020023b155 #7456
Hardware name: linux,dummy-virt (DT)
pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : __might_sleep+0xf4/0x140
lr : __might_sleep+0xf4/0x140
sp : ffff80008c5e7830
x29: ffff80008c5e7830 x28: ffff0000d93088c0 x27: ffff60001c2d7230
x26: dfff800000000000 x25: ffff0000e16b9180 x24: ffff80008c5e7a50
x23: 1ffff000118bcf4a x22: ffff0000e16b9180 x21: ffff0000e16b9180
x20: 000000000000011b x19: ffff80008310fac0 x18: 1ffff000118bcd90
x17: 30303c5b20746120 x16: 74657320313d6574 x15: 0720072007200720
x14: 0720072007200720 x13: 0720072007200720 x12: ffff600036c64f0b
x11: 1fffe00036c64f0a x10: ffff600036c64f0a x9 : dfff800000000000
x8 : 00009fffc939b0f6 x7 : ffff0001b6327853 x6 : 0000000000000001
x5 : ffff0001b6327850 x4 : ffff600036c64f0b x3 : ffff8000803c35bc
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000e16b9180
Call trace:
 __might_sleep+0xf4/0x140
 mutex_lock+0x84/0x124
 io_handle_tw_list+0xf4/0x260
 tctx_task_work_run+0x94/0x340
 io_run_task_work+0x1ec/0x3c0
 io_uring_cancel_generic+0x364/0x524
 io_sq_thread+0x820/0x124c
 ret_from_fork+0x10/0x20

The Linux kernel CVE team has assigned CVE-2024-50079 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.9 with commit af5d68f8892f and fixed in 6.11.5 with commit 887ba598d9cf
	Issue introduced in 6.9 with commit af5d68f8892f and fixed in 6.12-rc4 with commit 8f7033aa4089

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-50079
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	io_uring/io_uring.h

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/887ba598d9cfb537bdb3dfd95f087ff8a08cb74d
	https://git.kernel.org/stable/c/8f7033aa4089fbaf7a33995f0f2ee6c9d7b9ca1b