kernel/linux.git/io_uring, branch v5.15.99

io_uring/poll: allow some retries for poll triggering spuriously

2023-03-10T08:40:04+00:00

commit c16bda37594f83147b167d381d54c010024efecf upstream. If we get woken spuriously when polling and fail the operation with -EAGAIN again, then we generally only allow polling again if data had been transferred at some point. This is indicated with REQ_F_PARTIAL_IO. However, if the spurious poll triggers when the socket was originally empty, then we haven't transferred data yet and we will fail the poll re-arm. This either punts the socket to io-wq if it's blocking, or it fails the request with -EAGAIN if not. Neither condition is desirable, as the former will slow things down, while the latter will make the application confused. We want to ensure that a repeated poll trigger doesn't lead to infinite work making no progress, that's what the REQ_F_PARTIAL_IO check was for. But it doesn't protect against a loop post the first receive, and it's unnecessarily strict if we started out with an empty socket. Add a somewhat random retry count, just to put an upper limit on the potential number of retries that will be done. This should be high enough that we won't really hit it in practice, unless something needs to be aborted anyway. Cc: stable@vger.kernel.org # v5.10+ Link: https://github.com/axboe/liburing/issues/364 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: remove MSG_NOSIGNAL from recvmsg

2023-03-10T08:40:04+00:00

commit 7605c43d67face310b4b87dee1a28bc0c8cd8c0f upstream. MSG_NOSIGNAL is not applicable for the receiving side, SIGPIPE is generated when trying to write to a "broken pipe". AF_PACKET's packet_recvmsg() does enforce this, giving back EINVAL when MSG_NOSIGNAL is set - making it unuseable in io_uring's recvmsg. Remove MSG_NOSIGNAL from io_recvmsg_prep(). Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: David Lamparter Cc: Eric Dumazet Cc: Jens Axboe Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20230224150123.128346-1-equinox@diac24.net Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rsrc: disallow multi-source reg buffers

2023-03-10T08:40:04+00:00

commit edd478269640b360c6f301f2baa04abdda563ef3 upstream. If two or more mappings go back to back to each other they can be passed into io_uring to be registered as a single registered buffer. That would even work if mappings came from different sources, e.g. it's possible to mix in this way anon pages and pages from shmem or hugetlb. That is not a problem but it'd rather be less prone if we forbid such mixing. Cc: Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: add a conditional reschedule to the IOPOLL cancelation loop

2023-03-10T08:40:04+00:00

commit fcc926bb857949dbfa51a7d95f3f5ebc657f198c upstream. If the kernel is configured with CONFIG_PREEMPT_NONE, we could be sitting in a tight loop reaping events but not giving them a chance to finish. This results in a trace ala: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1 (t=5251 jiffies g=465 q=4135 ncpus=4) rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_sched state:R running task stack:0 pid:12 ppid:2 flags:0x00000008 Call trace: __switch_to+0xb0/0xc8 __schedule+0x43c/0x520 schedule+0x4c/0x98 schedule_timeout+0xbc/0xdc rcu_gp_fqs_loop+0x308/0x344 rcu_gp_kthread+0xd8/0xf0 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:kworker/u8:10 state:R running task stack:0 pid:89 ppid:2 flags:0x0000000a Workqueue: events_unbound io_ring_exit_work Call trace: __switch_to+0xb0/0xc8 0xffff0000c8fefd28 CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound io_ring_exit_work pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : io_do_iopoll+0x344/0x360 lr : io_do_iopoll+0xb8/0x360 sp : ffff800009bebc60 x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000 x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200 x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60 x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: io_do_iopoll+0x344/0x360 io_uring_try_cancel_requests+0x21c/0x334 io_ring_exit_work+0x90/0x40c process_one_work+0x1a4/0x254 worker_thread+0x1ec/0x258 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 Add a cond_resched() in the cancelation IOPOLL loop to fix this. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: mark task TASK_RUNNING before handling resume/task work

2023-03-10T08:40:04+00:00

commit 2f2bb1ffc9983e227424d0787289da5483b0c74f upstream. Just like for task_work, set the task mode to TASK_RUNNING before doing potential resume work. We're not holding any locks at this point, but we may have already set the task state to TASK_INTERRUPTIBLE in preparation for going to sleep waiting for events. Ensure that we set it back to TASK_RUNNING if we have work to process, to avoid warnings on calling blocking operations with !TASK_RUNNING. Fixes: b5d3ae202fbf ("io_uring: handle TIF_NOTIFY_RESUME when checking for task_work") Reported-by: kernel test robot Link: https://lore.kernel.org/oe-lkp/202302062208.24d3e563-oliver.sang@intel.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: handle TIF_NOTIFY_RESUME when checking for task_work

2023-03-10T08:40:03+00:00

commit b5d3ae202fbfe055aa2a8ae8524531ee1dcab717 upstream. If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work() for PF_IO_WORKER threads. They never return to usermode, hence never get a chance to process any items that are marked by this flag. Most notably this includes the final put of files, but also any throttling markers set by block cgroups. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: ensure that io_init_req() passes in the right issue_flags

2023-03-03T14:14:08+00:00

We can't use 0 here, as io_init_req() is always invoked with the ctx uring_lock held. Newer kernels have IO_URING_F_UNLOCKED for this, but previously we used IO_URING_F_NONBLOCK to indicate this as well. Fixes: cf7f9cd50013 ("io_uring: add missing lock in io_get_file_fixed") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: add missing lock in io_get_file_fixed

2023-03-03T10:45:54+00:00

io_get_file_fixed will access io_uring's context. Lock it if it is invoked unlocked (eg via io-wq) to avoid a race condition with fixed files getting unregistered. No single upstream patch exists for this issue, it was fixed as part of the file assignment changes that went into the 5.18 cycle. Signed-off-by: Jheng, Bing-Jhong Billy Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: remove leftover debug statement

2023-01-24T06:22:49+00:00

commit 5c61795ea97c170347c5c4af0c159bd877b8af71 upstream. This debug statement was never meant to go into the upstream release, kill it off before it ends up in a release. It was just part of the testing for the initial version of the patch. Fixes: 2ec33a6c3cca ("io_uring/rw: ensure kiocb_end_write() is always called") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: ensure kiocb_end_write() is always called

2023-01-24T06:22:49+00:00

commit 2ec33a6c3cca9fe2465e82050c81f5ffdc508b36 upstream. A previous commit moved the notifications and end-write handling, but it is now missing a few spots where we also want to call both of those. Without that, we can potentially be missing file notifications, and more importantly, have an imbalance in the super_block writers sem accounting. Fixes: b000145e9907 ("io_uring/rw: defer fsnotify calls to task context") Reported-by: Dave Chinner Link: https://lore.kernel.org/all/20221010050319.GC2703033@dread.disaster.area/ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman