FAILED: patch "[PATCH] io_uring/poll: serialize poll linked timer start with poll" failed to apply to 6.3-stable tree

PATCH [email protected] 2 participants 2 messages Jun 23, 2023

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Stable branch io_uring

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[email protected]

author maintainer

2023-06-23 09:29 UTC #0 lore raw

The patch below does not apply to the 6.3-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.3.y
git checkout FETCH_HEAD
git cherry-pick -x ef7dfac51d8ed961b742218f526bd589f3900a59
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023062306-omen-dance-80f0@gregkh' --subject-prefix 'PATCH 6.3.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ef7dfac51d8ed961b742218f526bd589f3900a59 Mon Sep 17 00:00:00 2001
From: Jens Axboe <[email protected]>
Date: Sat, 17 Jun 2023 19:50:24 -0600
Subject: [PATCH] io_uring/poll: serialize poll linked timer start with poll
removal

We selectively grab the ctx->uring_lock for poll update/removal, but we really should grab it from the start to fully synchronize with linked timeouts. Normally this is indeed the case, but if requests are forced async by the application, we don't fully cover removal and timer disarm within the uring_lock.

Make this simpler by having consistent locking state for poll removal.

Cc [email protected] # 6.1+

Reported-by Querijn Voet <[email protected]>

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

io_uring/poll.c +4 -5

index c90e47dc1e29..a78b8af7d9ab 100644
@@ -977,8 +977,9 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 	struct io_hash_bucket *bucket;
 	struct io_kiocb *preq;
 	int ret2, ret = 0;
-	struct io_tw_state ts = {};
+	struct io_tw_state ts = { .locked = true };
 
+	io_ring_submit_lock(ctx, issue_flags);
 	preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table, &bucket);
 	ret2 = io_poll_disarm(preq);
 	if (bucket)

@@ -990,12 +991,10 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 		goto out;
 	}
 
-	io_ring_submit_lock(ctx, issue_flags);
 	preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table_locked, &bucket);
 	ret2 = io_poll_disarm(preq);
 	if (bucket)
 		spin_unlock(&bucket->lock);
-	io_ring_submit_unlock(ctx, issue_flags);
 	if (ret2) {
 		ret = ret2;
 		goto out;

@@ -1019,7 +1018,7 @@ found:
 		if (poll_update->update_user_data)
 			preq->cqe.user_data = poll_update->new_user_data;
 
-		ret2 = io_poll_add(preq, issue_flags);
+		ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
 		/* successfully updated, don't complete poll request */
 		if (!ret2 || ret2 == -EIOCBQUEUED)
 			goto out;

@@ -1027,9 +1026,9 @@ found:
 
 	req_set_fail(preq);
 	io_req_set_res(preq, -ECANCELED, 0);
-	ts.locked = !(issue_flags & IO_URING_F_UNLOCKED);
 	io_req_task_complete(preq, &ts);
 out:
+	io_ring_submit_unlock(ctx, issue_flags);
 	if (ret < 0) {
 		req_set_fail(req);
 		return ret;

Jens Axboe

maintainer

2023-06-23 14:00 UTC #1 lore raw

Quoted 6 lines · On 6/23/23 3:29?AM, [email protected] wrote:

The patch below does not apply to the 6.3-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Quoted 8 lines

To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.3.y
git checkout FETCH_HEAD
git cherry-pick -x ef7dfac51d8ed961b742218f526bd589f3900a59
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023062306-omen-dance-80f0@gregkh' --subject-prefix 'PATCH 6.3.y' HEAD^..

Here's this one for 6.3-stable.

Signature · 1 line

Jens Axboe

From 6d4684e81a28a9647e263a532281bb3a020282fc Mon Sep 17 00:00:00 2001
From: Jens Axboe <[email protected]>
Date: Sat, 17 Jun 2023 19:50:24 -0600
Subject: [PATCH] io_uring/poll: serialize poll linked timer start with poll
removal

Commit ef7dfac51d8ed961b742218f526bd589f3900a59 upstream.