If there are no requests at the time __io_uring_task_cancel() is called, tctx_inflight() returns zero and and it terminates not getting a chance to go through __io_uring_files_cancel() and do io_disable_sqo_submit(). And we absolutely want them disabled by the time cancellation ends. Also a fix potential false positive warning because of ctx->sq_data check before io_disable_sqo_submit(). Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- To not grow diffstat now will be cleaned for-next fs/io_uring.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index d494c4269fc5..0d50845f1f3f 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8937,10 +8937,12 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, { struct task_struct *task = current; - if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { + if (ctx->flags & IORING_SETUP_SQPOLL) { /* for SQPOLL only sqo_task has task notes */ WARN_ON_ONCE(ctx->sqo_task != current); io_disable_sqo_submit(ctx); + } + if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { task = ctx->sq_data->thread; atomic_inc(&task->io_uring->in_idle); io_sq_thread_park(ctx->sq_data); @@ -9085,6 +9087,10 @@ void __io_uring_task_cancel(void) /* make sure overflow events are dropped */ atomic_inc(&tctx->in_idle); + /* trigger io_disable_sqo_submit() */ + if (tctx->sqpoll) + __io_uring_files_cancel(NULL); + do { /* read completions before cancelations */ inflight = tctx_inflight(tctx); -- 2.24.0
On 1/16/21 4:37 PM, Pavel Begunkov wrote:
> If there are no requests at the time __io_uring_task_cancel() is called,
> tctx_inflight() returns zero and and it terminates not getting a chance
> to go through __io_uring_files_cancel() and do
> io_disable_sqo_submit(). And we absolutely want them disabled by the
> time cancellation ends.
>
> Also a fix potential false positive warning because of ctx->sq_data
> check before io_disable_sqo_submit().
>
> Reported-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>
> To not grow diffstat now will be cleaned for-next
>
> fs/io_uring.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index d494c4269fc5..0d50845f1f3f 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -8937,10 +8937,12 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
> {
> struct task_struct *task = current;
>
> - if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
> + if (ctx->flags & IORING_SETUP_SQPOLL) {
> /* for SQPOLL only sqo_task has task notes */
> WARN_ON_ONCE(ctx->sqo_task != current);
> io_disable_sqo_submit(ctx);
> + }
> + if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
> task = ctx->sq_data->thread;
> atomic_inc(&task->io_uring->in_idle);
> io_sq_thread_park(ctx->sq_data);
Maybe just nest that inside?
if (ctx->flags & IORING_SETUP_SQPOLL) {
/* for SQPOLL only sqo_task has task notes */
WARN_ON_ONCE(ctx->sqo_task != current);
io_disable_sqo_submit(ctx);
if (ctx->sq_data) {
...
}
}
That'd look a bit cleaner imho.
--
Jens Axboe
On 17/01/2021 02:13, Jens Axboe wrote:
> On 1/16/21 4:37 PM, Pavel Begunkov wrote:
>> If there are no requests at the time __io_uring_task_cancel() is called,
>> tctx_inflight() returns zero and and it terminates not getting a chance
>> to go through __io_uring_files_cancel() and do
>> io_disable_sqo_submit(). And we absolutely want them disabled by the
>> time cancellation ends.
>>
>> Also a fix potential false positive warning because of ctx->sq_data
>> check before io_disable_sqo_submit().
>>
>> Reported-by: Jens Axboe <axboe@kernel.dk>
>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
>> ---
>>
>> To not grow diffstat now will be cleaned for-next
>>
>> fs/io_uring.c | 8 +++++++-
>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index d494c4269fc5..0d50845f1f3f 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -8937,10 +8937,12 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
>> {
>> struct task_struct *task = current;
>>
>> - if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
>> + if (ctx->flags & IORING_SETUP_SQPOLL) {
>> /* for SQPOLL only sqo_task has task notes */
>> WARN_ON_ONCE(ctx->sqo_task != current);
>> io_disable_sqo_submit(ctx);
>> + }
>> + if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
>> task = ctx->sq_data->thread;
>> atomic_inc(&task->io_uring->in_idle);
>> io_sq_thread_park(ctx->sq_data);
>
> Maybe just nest that inside?
>
> if (ctx->flags & IORING_SETUP_SQPOLL) {
> /* for SQPOLL only sqo_task has task notes */
> WARN_ON_ONCE(ctx->sqo_task != current);
> io_disable_sqo_submit(ctx);
> if (ctx->sq_data) {
> ...
> }
> }
>
> That'd look a bit cleaner imho.
second thought, it can't even happen because if not set we failed
during creation, and it has its own disable hooks.
sent v2 without that part
--
Pavel Begunkov