Re: FAILED: patch "[PATCH] io_uring/rw: fix missing ERESTARTSYS conversion in read paths" failed to apply to 6.1-stable tree

[Jens Axboe <axboe@kernel.dk>]

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On 7/29/26 7:50 AM, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 6.1-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 <stable@vger.kernel.org>.
> 
> 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-6.1.y
> git checkout FETCH_HEAD
> git cherry-pick -x ab05caca123c6d0b41850b7c05b246e4dca4a770
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072912-barn-caddy-3cea@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'
> 
> Possible dependencies:

Here's a version for 6.12 - which begs the question, why aren't we just
having LLMs do this work? Is it really worth punting this to the
maintainer? We could still punt for review, but trivial conflict
resolution seems like an area where we'd be better of having an LLM do
it. At least compared to using maintainer time.

-- 
Jens Axboe

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From 694056a4170df694f0689aa62d413f8728638c9b Mon Sep 17 00:00:00 2001
From: Yitang Yang <yi1tang.yang@gmail.com>
Date: Wed, 22 Jul 2026 20:45:51 +0800
Subject: [PATCH] io_uring/rw: fix missing ERESTARTSYS conversion in read paths

Commit ab05caca123c6d0b41850b7c05b246e4dca4a770 upstream.

Both read and write may receive internal restart error codes from
the filesystem layer and should be converted to -EINTR. However,
when multishot read support was added, the error code normalization
was lost for both io_read() and io_read_mshot().

Extract the conversion into io_fixup_restart_res() and apply it
in all three locations: io_rw_done(), io_read(), and io_read_mshot().

Fixes: a08d195b586a ("io_uring/rw: split io_read() into a helper")
Cc: stable@vger.kernel.org
Signed-off-by: Yitang Yang <yi1tang.yang@gmail.com>
Link: https://patch.msgid.link/20260722124551.130563-1-yi1tang.yang@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/rw.c | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index a744cb5d235a..a74664c4a05e 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -560,6 +560,24 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
 	smp_store_release(&req->iopoll_completed, 1);
 }
 
+static inline ssize_t io_fixup_restart_res(ssize_t ret)
+{
+	switch (ret) {
+	case -ERESTARTSYS:
+	case -ERESTARTNOINTR:
+	case -ERESTARTNOHAND:
+	case -ERESTART_RESTARTBLOCK:
+		/*
+		 * We can't just restart the syscall, since previously
+		 * submitted sqes may already be in progress. Just fail
+		 * this IO with EINTR.
+		 */
+		return -EINTR;
+	default:
+		return ret;
+	}
+}
+
 static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
 {
 	/* IO was queued async, completion will happen later */
@@ -567,21 +585,8 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
 		return;
 
 	/* transform internal restart error codes */
-	if (unlikely(ret < 0)) {
-		switch (ret) {
-		case -ERESTARTSYS:
-		case -ERESTARTNOINTR:
-		case -ERESTARTNOHAND:
-		case -ERESTART_RESTARTBLOCK:
-			/*
-			 * We can't just restart the syscall, since previously
-			 * submitted sqes may already be in progress. Just fail
-			 * this IO with EINTR.
-			 */
-			ret = -EINTR;
-			break;
-		}
-	}
+	if (unlikely(ret < 0))
+		ret = io_fixup_restart_res(ret);
 
 	INDIRECT_CALL_2(kiocb->ki_complete, io_complete_rw_iopoll,
 			io_complete_rw, kiocb, ret);
@@ -961,7 +966,8 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 
 	if (req->flags & REQ_F_BUFFERS_COMMIT)
 		io_kbuf_recycle(req, sel.buf_list, issue_flags);
-	return ret;
+
+	return io_fixup_restart_res(ret);
 }
 
 int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
@@ -995,8 +1001,10 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
 		return -EAGAIN;
 	} else if (ret <= 0) {
 		io_kbuf_recycle(req, sel.buf_list, issue_flags);
-		if (ret < 0)
+		if (ret < 0) {
+			ret = io_fixup_restart_res(ret);
 			req_set_fail(req);
+		}
 	} else if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
 		cflags = io_put_kbuf(req, ret, sel.buf_list);
 	} else {
-- 
2.53.0