This is a note to let you know that I've just added the patch titled
io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-pass-in-epoll_uring_wake-for-eventfd-signaling-and-wakeups.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4029c28b8d6792778bdadc4e431be30302ff4a3b Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Fri, 23 Dec 2022 07:04:49 -0700
Subject: io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups
From: Jens Axboe <axboe@xxxxxxxxx>
[ Upstream commit 4464853277d0ccdb9914608dd1332f0fa2f9846f ]
Pass in EPOLL_URING_WAKE when signaling eventfd or doing poll related
wakups, so that we can check for a circular event dependency between
eventfd and epoll. If this flag is set when our wakeup handlers are
called, then we know we have a dependency that needs to terminate
multishot requests.
eventfd and epoll are the only such possible dependencies.
Cc: stable@xxxxxxxxxxxxxxx # 6.0
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io_uring.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1626,13 +1626,15 @@ static void io_cqring_ev_posted(struct i
* wake as many waiters as we need to.
*/
if (wq_has_sleeper(&ctx->cq_wait))
- wake_up_all(&ctx->cq_wait);
+ __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
+ poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
if (io_should_trigger_evfd(ctx))
- eventfd_signal(ctx->cq_ev_fd, 1);
+ eventfd_signal_mask(ctx->cq_ev_fd, 1, EPOLL_URING_WAKE);
if (waitqueue_active(&ctx->poll_wait))
- wake_up_interruptible(&ctx->poll_wait);
+ __wake_up(&ctx->poll_wait, TASK_INTERRUPTIBLE, 0,
+ poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
}
static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
@@ -1642,12 +1644,14 @@ static void io_cqring_ev_posted_iopoll(s
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (waitqueue_active(&ctx->cq_wait))
- wake_up_all(&ctx->cq_wait);
+ __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
+ poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
}
if (io_should_trigger_evfd(ctx))
- eventfd_signal(ctx->cq_ev_fd, 1);
+ eventfd_signal_mask(ctx->cq_ev_fd, 1, EPOLL_URING_WAKE);
if (waitqueue_active(&ctx->poll_wait))
- wake_up_interruptible(&ctx->poll_wait);
+ __wake_up(&ctx->poll_wait, TASK_INTERRUPTIBLE, 0,
+ poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
}
/* Returns true if there are no backlogged entries after the flush */
@@ -5477,8 +5481,17 @@ static int io_poll_wake(struct wait_queu
if (mask && !(mask & poll->events))
return 0;
- if (io_poll_get_ownership(req))
+ if (io_poll_get_ownership(req)) {
+ /*
+ * If we trigger a multishot poll off our own wakeup path,
+ * disable multishot as there is a circular dependency between
+ * CQ posting and triggering the event.
+ */
+ if (mask & EPOLL_URING_WAKE)
+ poll->events |= EPOLLONESHOT;
+
__io_poll_execute(req, mask);
+ }
return 1;
}
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-5.10/x86-process-setup-io_threads-more-like-normal-user-space-threads.patch
queue-5.10/powerpc-add-support-for-tif_notify_signal.patch
queue-5.10/eventfd-provide-a-eventfd_signal_mask-helper.patch
queue-5.10/fs-provide-locked-helper-variant-of-close_fd_get_file.patch
queue-5.10/relay-fix-type-mismatch-when-allocating-memory-in-re.patch
queue-5.10/eventfd-change-int-to-__u64-in-eventfd_signal-ifndef.patch
queue-5.10/io_uring-pass-in-epoll_uring_wake-for-eventfd-signaling-and-wakeups.patch
queue-5.10/blk-mq-fix-possible-memleak-when-register-hctx-faile.patch
queue-5.10/fix-handling-of-nd-depth-on-lookup_cached-failures-in-try_to_unlazy.patch
queue-5.10/net-provide-__sys_shutdown_sock-that-takes-a-socket.patch
queue-5.10/task_work-unconditionally-run-task_work-from-get_signal.patch
queue-5.10/openrisc-add-support-for-tif_notify_signal.patch
queue-5.10/signal-add-task_sigpending-helper.patch
queue-5.10/net-remove-cmsg-restriction-from-io_uring-based-send-recvmsg-calls.patch
queue-5.10/alpha-add-support-for-tif_notify_signal.patch
queue-5.10/nios32-add-support-for-tif_notify_signal.patch
queue-5.10/ia64-don-t-call-handle_signal-unless-there-s-actually-a-signal-queued.patch
queue-5.10/task_work-remove-legacy-twa_signal-path.patch
queue-5.10/revert-proc-don-t-allow-async-path-resolution-of-proc-self-components.patch
queue-5.10/m68k-add-support-for-tif_notify_signal.patch
queue-5.10/s390-add-support-for-tif_notify_signal.patch
queue-5.10/um-add-support-for-tif_notify_signal.patch
queue-5.10/tools-headers-uapi-sync-openat2.h-with-the-kernel-sources.patch
queue-5.10/kernel-provide-create_io_thread-helper.patch
queue-5.10/iov_iter-add-helper-to-save-iov_iter-state.patch
queue-5.10/arc-unbork-5.11-bootup-fix-snafu-in-_tif_notify_signal-handling.patch
queue-5.10/arch-ensure-parisc-powerpc-handle-pf_io_worker-in-copy_thread.patch
queue-5.10/csky-add-support-for-tif_notify_signal.patch
queue-5.10/arm-add-support-for-tif_notify_signal.patch
queue-5.10/kernel-stop-masking-signals-in-create_io_thread.patch
queue-5.10/fs-expose-lookup_cached-through-openat2-resolve_cached.patch
queue-5.10/task_work-add-helper-for-more-targeted-task_work-canceling.patch
queue-5.10/nds32-add-support-for-tif_notify_signal.patch
queue-5.10/signal-kill-jobctl_task_work.patch
queue-5.10/hexagon-add-support-for-tif_notify_signal.patch
queue-5.10/sh-add-support-for-tif_notify_signal.patch
queue-5.10/riscv-add-support-for-tif_notify_signal.patch
queue-5.10/h8300-add-support-for-tif_notify_signal.patch
queue-5.10/io_uring-import-5.15-stable-io_uring.patch
queue-5.10/sparc-add-support-for-tif_notify_signal.patch
queue-5.10/blktrace-fix-output-non-blktrace-event-when-blk_clas.patch
queue-5.10/eventpoll-add-epoll_uring_wake-poll-wakeup-flag.patch
queue-5.10/parisc-add-support-for-tif_notify_signal.patch
queue-5.10/entry-add-support-for-tif_notify_signal.patch
queue-5.10/x86-wire-up-tif_notify_signal.patch
queue-5.10/task_work-use-tif_notify_signal-if-available.patch
queue-5.10/drbd-fix-an-invalid-memory-access-caused-by-incorrec.patch
queue-5.10/kernel-don-t-call-do_exit-for-pf_io_worker-threads.patch
queue-5.10/kernel-allow-fork-with-tif_notify_signal-pending.patch
queue-5.10/pata_ipx4xx_cf-fix-unsigned-comparison-with-less-tha.patch
queue-5.10/mips-add-support-for-tif_notify_signal.patch
queue-5.10/xtensa-add-support-for-tif_notify_signal.patch
queue-5.10/c6x-add-support-for-tif_notify_signal.patch
queue-5.10/microblaze-add-support-for-tif_notify_signal.patch
queue-5.10/net-add-accept-helper-not-installing-fd.patch
queue-5.10/ia64-add-support-for-tif_notify_signal.patch
queue-5.10/arm64-add-support-for-tif_notify_signal.patch
queue-5.10/arc-add-support-for-tif_notify_signal.patch
queue-5.10/revert-proc-don-t-allow-async-path-resolution-of-proc-thread-self-components.patch
queue-5.10/fs-make-do_renameat2-take-struct-filename.patch
queue-5.10/kernel-remove-checking-for-tif_notify_signal.patch
queue-5.10/arch-setup-pf_io_worker-threads-like-pf_kthread.patch
queue-5.10/nvme-pci-fix-mempool-alloc-size.patch
queue-5.10/fs-add-support-for-lookup_cached.patch
