linux-stable.git/io_uring/tw.c, branch master

io_uring: mark known and harmless racy ctx->int_flags uses

2026-03-16T21:33:10+00:00

There are a few of these, where flags are read outside of the
uring_lock, yet it's harmless to race on them.

Signed-off-by: Jens Axboe

io_uring: switch struct io_ring_ctx internal bitfields to flags

2026-03-16T21:32:59+00:00

Bitfields cannot be set and checked atomically, and this makes it more
clear that these are indeed in shared storage and must be checked and
set in a sane fashion. This is in preparation for annotating a few of
the known racy, but harmless, flags checking.

No intended functional changes in this patch.

Reviewed-by: Gabriel Krisman Bertazi 
Signed-off-by: Jens Axboe

io_uring: ensure ctx->rings is stable for task work flags manipulation

2026-03-11T20:35:16+00:00

If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while
the ring is being resized, it's possible for the OR'ing of
IORING_SQ_TASKRUN to happen in the small window of swapping into the
new rings and the old rings being freed.

Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is
protected by RCU. The task work flags manipulation is inside RCU
already, and if the resize ring freeing is done post an RCU synchronize,
then there's no need to add locking to the fast path of task work
additions.

Note: this is only done for DEFER_TASKRUN, as that's the only setup mode
that supports ring resizing. If this ever changes, then they too need to
use the io_ctx_mark_taskrun() helper.

Link: https://lore.kernel.org/io-uring/20260309062759.482210-1-naup96721@gmail.com/
Cc: stable@vger.kernel.org
Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS")
Reported-by: Hao-Yu Yang 
Suggested-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

io_uring: split out CQ waiting code into wait.c

2026-01-22T16:21:16+00:00

Move the completion queue waiting and scheduling code out of io_uring.c
into a dedicated wait.c file. This further removes code out of the
main io_uring C and header file, and into a topical new file.

Signed-off-by: Jens Axboe

io_uring: split out task work code into tw.c

2026-01-22T16:20:17+00:00

Move the task work handling code out of io_uring.c into a new tw.c file.
This includes the local work, normal work, and fallback work handling
infrastructure.

The associated tw.h header contains io_should_terminate_tw() as a static
inline helper, along with the necessary function declarations.

Signed-off-by: Jens Axboe