io_uring/timeout: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initi

io_uring/timeout: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initialization of
hrtimer::function with the new setup mechanism.

Signed-off-by: Nam Cao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/80ca8d959f2cc67c75f6d61008e3bebfe7fbc30a.1738746821.git.namcao@linutronix.de

show more ...

io_uring: introduce type alias for io_tw_state

In preparation for changing how io_tw_state is passed, introduce a type
alias io_tw_token_t for struct io_tw_state *. This allows for changing
the repr

io_uring: introduce type alias for io_tw_state

In preparation for changing how io_tw_state is passed, introduce a type
alias io_tw_token_t for struct io_tw_state *. This allows for changing
the representation in one place, without having to update the many
functions that just forward their struct io_tw_state * argument.

Also add a comment to struct io_tw_state to explain its purpose.

Signed-off-by: Caleb Sander Mateos <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring/alloc_cache: get rid of _nocache() helper

Just allow passing in NULL for the cache, if the type in question
doesn't have a cache associated with it.

Signed-off-by: Jens Axboe <axboe@kernel

io_uring/alloc_cache: get rid of _nocache() helper

Just allow passing in NULL for the cache, if the type in question
doesn't have a cache associated with it.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring/timeout: fix multishot updates

After update only the first shot of a multishot timeout request adheres
to the new timeout value while all subsequent retries continue to use
the old value. D

io_uring/timeout: fix multishot updates

After update only the first shot of a multishot timeout request adheres
to the new timeout value while all subsequent retries continue to use
the old value. Don't forget to update the timeout stored in struct
io_timeout_data.

Cc: [email protected]
Fixes: ea97f6c8558e8 ("io_uring: add support for multishot timeouts")
Reported-by: Christian Mazakas <[email protected]>
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/e6516c3304eb654ec234cfa65c88a9579861e597.1736015288.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring/timeout: flush timeouts outside of the timeout lock

syzbot reports that a recent fix causes nesting issues between the (now)
raw timeoutlock and the eventfd locking:

======================

io_uring/timeout: flush timeouts outside of the timeout lock

syzbot reports that a recent fix causes nesting issues between the (now)
raw timeoutlock and the eventfd locking:

=============================
[ BUG: Invalid wait context ]
6.13.0-rc4-00080-g9828a4c0901f #29 Not tainted
-----------------------------
kworker/u32:0/68094 is trying to lock:
ffff000014d7a520 (&ctx->wqh#2){..-.}-{3:3}, at: eventfd_signal_mask+0x64/0x180
other info that might help us debug this:
context-{5:5}
6 locks held by kworker/u32:0/68094:
#0: ffff0000c1d98148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x4e8/0xfc0
#1: ffff80008d927c78 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x53c/0xfc0
#2: ffff0000c59bc3d8 (&ctx->completion_lock){+.+.}-{3:3}, at: io_kill_timeouts+0x40/0x180
#3: ffff0000c59bc358 (&ctx->timeout_lock){-.-.}-{2:2}, at: io_kill_timeouts+0x48/0x180
#4: ffff800085127aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x8/0x38
#5: ffff800085127aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x8/0x38
stack backtrace:
CPU: 7 UID: 0 PID: 68094 Comm: kworker/u32:0 Not tainted 6.13.0-rc4-00080-g9828a4c0901f #29
Hardware name: linux,dummy-virt (DT)
Workqueue: iou_exit io_ring_exit_work
Call trace:
show_stack+0x1c/0x30 (C)
__dump_stack+0x24/0x30
dump_stack_lvl+0x60/0x80
dump_stack+0x14/0x20
__lock_acquire+0x19f8/0x60c8
lock_acquire+0x1a4/0x540
_raw_spin_lock_irqsave+0x90/0xd0
eventfd_signal_mask+0x64/0x180
io_eventfd_signal+0x64/0x108
io_req_local_work_add+0x294/0x430
__io_req_task_work_add+0x1c0/0x270
io_kill_timeout+0x1f0/0x288
io_kill_timeouts+0xd4/0x180
io_uring_try_cancel_requests+0x2e8/0x388
io_ring_exit_work+0x150/0x550
process_one_work+0x5e8/0xfc0
worker_thread+0x7ec/0xc80
kthread+0x24c/0x300
ret_from_fork+0x10/0x20

because after the preempt-rt fix for the timeout lock nesting inside
the io-wq lock, we now have the eventfd spinlock nesting inside the
raw timeout spinlock.

Rather than play whack-a-mole with other nesting on the timeout lock,
split the deletion and killing of timeouts so queueing the task_work
for the timeout cancelations can get done outside of the timeout lock.

Reported-by: [email protected]
Fixes: 020b40f35624 ("io_uring: make ctx->timeout_lock a raw spinlock")
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: Move old async data allocation helper to header

There are two remaining uses of the old async data allocator that do not
rely on the alloc cache. I don't want to make them use the new
all

io_uring: Move old async data allocation helper to header

There are two remaining uses of the old async data allocator that do not
rely on the alloc cache. I don't want to make them use the new
allocator helper because that would require a if(cache) check, which
will result in dead code for the cached case (for callers passing a
cache, gcc can't prove the cache isn't NULL, and will therefore preserve
the check. Since this is an inline function and just a few lines long,
keep a second helper to deal with cases where we don't have an async
data cache.

No functional change intended here. This is just moving the helper
around and making it inline.

Signed-off-by: Gabriel Krisman Bertazi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: make ctx->timeout_lock a raw spinlock

Chase reports that their tester complaints about a locking context
mismatch:

=============================
[ BUG: Invalid wait context ]
6.13.0-rc1-g

io_uring: make ctx->timeout_lock a raw spinlock

Chase reports that their tester complaints about a locking context
mismatch:

=============================
[ BUG: Invalid wait context ]
6.13.0-rc1-gf137f14b7ccb-dirty #9 Not tainted
-----------------------------
syz.1.25198/182604 is trying to lock:
ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: spin_lock_irq
include/linux/spinlock.h:376 [inline]
ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at:
io_match_task_safe io_uring/io_uring.c:218 [inline]
ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at:
io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204
other info that might help us debug this:
context-{5:5}
1 lock held by syz.1.25198/182604:
#0: ffff88802b7d48c0 (&acct->lock){+.+.}-{2:2}, at:
io_acct_cancel_pending_work+0x2d/0x6b0 io_uring/io-wq.c:1049
stack backtrace:
CPU: 0 UID: 0 PID: 182604 Comm: syz.1.25198 Not tainted
6.13.0-rc1-gf137f14b7ccb-dirty #9
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x82/0xd0 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline]
check_wait_context kernel/locking/lockdep.c:4898 [inline]
__lock_acquire+0x883/0x3c80 kernel/locking/lockdep.c:5176
lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5849
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
io_match_task_safe io_uring/io_uring.c:218 [inline]
io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204
io_acct_cancel_pending_work+0xb8/0x6b0 io_uring/io-wq.c:1052
io_wq_cancel_pending_work io_uring/io-wq.c:1074 [inline]
io_wq_cancel_cb+0xb0/0x390 io_uring/io-wq.c:1112
io_uring_try_cancel_requests+0x15e/0xd70 io_uring/io_uring.c:3062
io_uring_cancel_generic+0x6ec/0x8c0 io_uring/io_uring.c:3140
io_uring_files_cancel include/linux/io_uring.h:20 [inline]
do_exit+0x494/0x27a0 kernel/exit.c:894
do_group_exit+0xb3/0x250 kernel/exit.c:1087
get_signal+0x1d77/0x1ef0 kernel/signal.c:3017
arch_do_signal_or_restart+0x79/0x5b0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
do_syscall_64+0xd8/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

which is because io_uring has ctx->timeout_lock nesting inside the
io-wq acct lock, the latter of which is used from inside the scheduler
and hence is a raw spinlock, while the former is a "normal" spinlock
and can hence be sleeping on PREEMPT_RT.

Change ctx->timeout_lock to be a raw spinlock to solve this nesting
dependency on PREEMPT_RT=y.

Reported-by: chase xd <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: Remove redundant hrtimer's callback function setup

The IORING_OP_TIMEOUT command uses hrtimer underneath. The timer's callback
function is setup in io_timeout(), and then the callback func

io_uring: Remove redundant hrtimer's callback function setup

The IORING_OP_TIMEOUT command uses hrtimer underneath. The timer's callback
function is setup in io_timeout(), and then the callback function is setup
again when the timer is rearmed.

Since the callback function is the same for both cases, the latter setup is
redundant, therefore remove it.

Signed-off-by: Nam Cao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Jens Axboe <[email protected]:
Link: https://lore.kernel.org/all/07b28dfd5691478a2d250f379c8b90dd37f9bb9a.1730386209.git.namcao@linutronix.de

show more ...

io_uring: move struct io_kiocb from task_struct to io_uring_task

Rather than store the task_struct itself in struct io_kiocb, store
the io_uring specific task_struct. The life times are the same in

io_uring: move struct io_kiocb from task_struct to io_uring_task

Rather than store the task_struct itself in struct io_kiocb, store
the io_uring specific task_struct. The life times are the same in terms
of io_uring, and this avoids doing some dereferences through the
task_struct. For the hot path of putting local task references, we can
deref req->tctx instead, which we'll need anyway in that function
regardless of whether it's local or remote references.

This is mostly straight forward, except the original task PF_EXITING
check needs a bit of tweaking. task_work is _always_ run from the
originating task, except in the fallback case, where it's run from a
kernel thread. Replace the potentially racy (in case of fallback work)
checks for req->task->flags with current->flags. It's either the still
the original task, in which case PF_EXITING will be sane, or it has
PF_KTHREAD set, in which case it's fallback work. Both cases should
prevent moving forward with the given request.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: move cancelations to be io_uring_task based

Right now the task_struct pointer is used as the key to match a task,
but in preparation for some io_kiocb changes, move it to using struct
io_u

io_uring: move cancelations to be io_uring_task based

Right now the task_struct pointer is used as the key to match a task,
but in preparation for some io_kiocb changes, move it to using struct
io_uring_task instead. No functional changes intended in this patch.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: fix io_match_task must_hold

The __must_hold annotation in io_match_task() uses a non existing
parameter "req", fix it.

Fixes: 6af3f48bf6156 ("io_uring: fix link traversal locking")
Signed

io_uring: fix io_match_task must_hold

The __must_hold annotation in io_match_task() uses a non existing
parameter "req", fix it.

Fixes: 6af3f48bf6156 ("io_uring: fix link traversal locking")
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/3e65ee7709e96507cef3d93291746f2c489f2307.1721819383.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring/timeout: remove duplicate initialization of the io_timeout list.

In the __io_timeout_prep function, the io_timeout list is initialized
twice, removing the meaningless second initialization.

io_uring/timeout: remove duplicate initialization of the io_timeout list.

In the __io_timeout_prep function, the io_timeout list is initialized
twice, removing the meaningless second initialization.

Signed-off-by: Ruyi Zhang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: refactor io_fill_cqe_req_aux

The restriction on multishot execution context disallowing io-wq is
driven by rules of io_fill_cqe_req_aux(), it should only be called in
the master task conte

io_uring: refactor io_fill_cqe_req_aux

The restriction on multishot execution context disallowing io-wq is
driven by rules of io_fill_cqe_req_aux(), it should only be called in
the master task context, either from the syscall path or in task_work.
Since task_work now always takes the ctx lock implying
IO_URING_F_COMPLETE_DEFER, we can just assume that the function is
always called with its defer argument set to true.

Kill the argument. Also rename the function for more consistency as
"fill" in CQE related functions was usually meant for raw interfaces
only copying data into the CQ without any locking, waking the user
and other accounting "post" functions take care of.

Signed-off-by: Pavel Begunkov <[email protected]>
Tested-by: Ming Lei <[email protected]>
Link: https://lore.kernel.org/r/93423d106c33116c7d06bf277f651aa68b427328.1710799188.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: remove struct io_tw_state::locked

ctx is always locked for task_work now, so get rid of struct
io_tw_state::locked. Note I'm stopping one step before removing
io_tw_state altogether, which

io_uring: remove struct io_tw_state::locked

ctx is always locked for task_work now, so get rid of struct
io_tw_state::locked. Note I'm stopping one step before removing
io_tw_state altogether, which is not empty, because it still serves the
purpose of indicating which function is a tw callback and forcing users
not to invoke them carelessly out of a wrong context. The removal can
always be done later.

Signed-off-by: Pavel Begunkov <[email protected]>
Tested-by: Ming Lei <[email protected]>
Link: https://lore.kernel.org/r/e95e1ea116d0bfa54b656076e6a977bc221392a4.1710799188.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: never overflow io_aux_cqe

Now all callers of io_aux_cqe() set allow_overflow to false, remove the
parameter and not allow overflowing auxilary multishot cqes.

When CQ is full the function

io_uring: never overflow io_aux_cqe

Now all callers of io_aux_cqe() set allow_overflow to false, remove the
parameter and not allow overflowing auxilary multishot cqes.

When CQ is full the function callers and all multishot requests in
general are expected to complete the request. That prevents indefinite
in-background grows of the overflow list and let's the userspace to
handle the backlog at its own pace.

Resubmitting a request should also be faster than accounting a bunch of
overflows, so it should be better for perf when it happens, but a well
behaving userspace should be trying to avoid overflows in any case.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/bb20d14d708ea174721e58bb53786b0521e4dd6d.1691757663.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: use cancelation match helper for poll and timeout requests

Get rid of the request vs io_cancel_data checking and just use the
exported helper for this.

Signed-off-by: Jens Axboe <axboe@ke

io_uring: use cancelation match helper for poll and timeout requests

Get rid of the request vs io_cancel_data checking and just use the
exported helper for this.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring/timeout: always set 'ctx' in io_cancel_data

In preparation for using a generic handler to match requests for
cancelation purposes, ensure that ctx is set in io_cancel_data. The
timeout hand

io_uring/timeout: always set 'ctx' in io_cancel_data

In preparation for using a generic handler to match requests for
cancelation purposes, ensure that ctx is set in io_cancel_data. The
timeout handlers don't check for this as it'll always match, but we'll
need it set going forward.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: cleanup io_aux_cqe() API

Everybody is passing in the request, so get rid of the io_ring_ctx and
explicit user_data pass-in. Both the ctx and user_data can be deduced
from the request at ha

io_uring: cleanup io_aux_cqe() API

Everybody is passing in the request, so get rid of the io_ring_ctx and
explicit user_data pass-in. Both the ctx and user_data can be deduced
from the request at hand.

Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: annotate offset timeout races

It's racy to read ->cached_cq_tail without taking proper measures
(usually grabbing ->completion_lock) as timeout requests with CQE
offsets do, however they h

io_uring: annotate offset timeout races

It's racy to read ->cached_cq_tail without taking proper measures
(usually grabbing ->completion_lock) as timeout requests with CQE
offsets do, however they have never had a good semantics for from
when they start counting. Annotate racy reads with data_race().

Reported-by: [email protected]
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/4de3685e185832a92a572df2be2c735d2e21a83d.1684506056.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: add support for multishot timeouts

A multishot timeout submission will repeatedly generate completions with
the IORING_CQE_F_MORE cflag set. Depending on the value of the `off'
field in th

io_uring: add support for multishot timeouts

A multishot timeout submission will repeatedly generate completions with
the IORING_CQE_F_MORE cflag set. Depending on the value of the `off'
field in the submission, these timeouts can either repeat indefinitely
until cancelled (`off' = 0) or for a fixed number of times (`off' > 0).

Only noseq timeouts (i.e. not dependent on the number of I/O
completions) are supported.

An indefinite timer will be cancelled if the CQ ever overflows.

Signed-off-by: David Wei <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: encapsulate task_work state

For task works we're passing around a bool pointer for whether the
current ring is locked or not, let's wrap it in a structure, that
will make it more opaque pr

io_uring: encapsulate task_work state

For task works we're passing around a bool pointer for whether the
current ring is locked or not, let's wrap it in a structure, that
will make it more opaque preventing abuse and will also help us
to pass more info in the future if needed.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: ease timeout flush locking requirements

We don't need completion_lock for timeout flushing, don't take it.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel

io_uring: ease timeout flush locking requirements

We don't need completion_lock for timeout flushing, don't take it.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/1e3dc657975ac445b80e7bdc40050db783a5935a.1670002973.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: revise completion_lock locking

io_kill_timeouts() doesn't post any events but queues everything to
task_work. Locking there is needed for protecting linked requests
traversing, we should g

io_uring: revise completion_lock locking

io_kill_timeouts() doesn't post any events but queues everything to
task_work. Locking there is needed for protecting linked requests
traversing, we should grab completion_lock directly instead of using
io_cq_[un]lock helpers. Same goes for __io_req_find_next_prep().

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/88e75d481a65dc295cb59722bb1cf76402d1c06b.1670002973.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: protect cq_timeouts with timeout_lock

Read cq_timeouts in io_flush_timeouts() only after taking the
timeout_lock, as it's protected by it. There are many places where we
also grab ->comple

io_uring: protect cq_timeouts with timeout_lock

Read cq_timeouts in io_flush_timeouts() only after taking the
timeout_lock, as it's protected by it. There are many places where we
also grab ->completion_lock, but for instance io_timeout_fn() doesn't
and still modifies cq_timeouts.

Cc: [email protected]
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/9c79544dd6cf5c4018cb1bab99cf481a93ea46ef.1670002973.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...

io_uring: remove io_req_tw_post_queue

Remove io_req_tw_post() and io_req_tw_post_queue(), we can use
io_req_task_complete() instead.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: htt

io_uring: remove io_req_tw_post_queue

Remove io_req_tw_post() and io_req_tw_post_queue(), we can use
io_req_task_complete() instead.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/b9b73c08022c7f1457023ac841f35c0100e70345.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

show more ...