[PATCH for-next] io_uring: ensure local task_work marks task as running

[Jens Axboe <axboe@kernel.dk>]

io_uring will run task_work from contexts that have been prepared for
waiting, and in doing so it'll implicitly set the task running again
to avoid issues with blocking conditions. The new deferred local
task_work doesn't do that, which can result in spews on this being
an invalid condition:



[  112.917576] do not call blocking ops when !TASK_RUNNING; state=1 set at [<00000000ad64af64>] prepare_to_wait_exclusive+0x3f/0xd0
[  112.983088] WARNING: CPU: 1 PID: 190 at kernel/sched/core.c:9819 __might_sleep+0x5a/0x60
[  112.987240] Modules linked in:
[  112.990504] CPU: 1 PID: 190 Comm: io_uring Not tainted 6.0.0-rc6+ #1617
[  113.053136] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
[  113.133650] RIP: 0010:__might_sleep+0x5a/0x60
[  113.136507] Code: ee 48 89 df 5b 31 d2 5d e9 33 ff ff ff 48 8b 90 30 0b 00 00 48 c7 c7 90 de 45 82 c6 05 20 8b 79 01 01 48 89 d1 e8 3a 49 77 00 <0f> 0b eb d1 66 90 0f 1f 44 00 00 9c 58 f6 c4 02 74 35 65 8b 05 ed
[  113.223940] RSP: 0018:ffffc90000537ca0 EFLAGS: 00010286
[  113.232903] RAX: 0000000000000000 RBX: ffffffff8246782c RCX: ffffffff8270bcc8
IOPS=133.15K, BW=520MiB/s, IOS/call=32/31
[  113.353457] RDX: ffffc90000537b50 RSI: 00000000ffffdfff RDI: 0000000000000001
[  113.358970] RBP: 00000000000003bc R08: 0000000000000000 R09: c0000000ffffdfff
[  113.361746] R10: 0000000000000001 R11: ffffc90000537b48 R12: ffff888103f97280
[  113.424038] R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
[  113.428009] FS:  00007f67ae7fc700(0000) GS:ffff88842fc80000(0000) knlGS:0000000000000000
[  113.432794] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  113.503186] CR2: 00007f67b8b9b3b0 CR3: 0000000102b9b005 CR4: 0000000000770ee0
[  113.507291] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  113.512669] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  113.574374] PKRU: 55555554
[  113.576800] Call Trace:
[  113.578325]  <TASK>
[  113.579799]  set_page_dirty_lock+0x1b/0x90
[  113.582411]  __bio_release_pages+0x141/0x160
[  113.673078]  ? set_next_entity+0xd7/0x190
[  113.675632]  blk_rq_unmap_user+0xaa/0x210
[  113.678398]  ? timerqueue_del+0x2a/0x40
[  113.679578]  nvme_uring_task_cb+0x94/0xb0
[  113.683025]  __io_run_local_work+0x8a/0x150
[  113.743724]  ? io_cqring_wait+0x33d/0x500
[  113.746091]  io_run_local_work.part.76+0x2e/0x60
[  113.750091]  io_cqring_wait+0x2e7/0x500
[  113.752395]  ? trace_event_raw_event_io_uring_req_failed+0x180/0x180
[  113.823533]  __x64_sys_io_uring_enter+0x131/0x3c0
[  113.827382]  ? switch_fpu_return+0x49/0xc0
[  113.830753]  do_syscall_64+0x34/0x80
[  113.832620]  entry_SYSCALL_64_after_hwframe+0x5e/0xc8

Ensure that we mark current as TASK_RUNNING for deferred task_work
as well.

Fixes: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Reported-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 3875ea897cdf..f359e24b46c3 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1215,6 +1215,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
 	if (llist_empty(&ctx->work_llist))
 		return 0;
 
+	__set_current_state(TASK_RUNNING);
 	locked = mutex_trylock(&ctx->uring_lock);
 	ret = __io_run_local_work(ctx, locked);
 	if (locked)

-- 
Jens Axboe