FAILED: patch "[PATCH] fuse: wait for FR_FINISHED on abort_on_kill to prevent" failed to apply to 7.1-stable tree

The patch below does not apply to the 7.1-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 <[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-7.1.y
git checkout FETCH_HEAD
git cherry-pick -x 64b0b5cacbd2fea88001464cb712c9dfc795b26e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026083100-flyable-tidings-a936@gregkh' --subject-prefix 'PATCH 7.1.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 64b0b5cacbd2fea88001464cb712c9dfc795b26e Mon Sep 17 00:00:00 2001
From: Rochan Avlur <[email protected]>
Date: Wed, 12 Aug 2026 20:58:36 -0700
Subject: [PATCH] fuse: wait for FR_FINISHED on abort_on_kill to prevent
use-after-free

The abort_on_kill path in request_wait_answer() calls fuse_abort_conn() and returns without waiting for FR_FINISHED. If fuse_dev_do_write() is concurrently processing the same request (FR_LOCKED set), the caller frees req->args while it is still being accessed, causing a use-after-free.

Fix this by jumping to the existing wait_event(FR_FINISHED) instead of returning early. The wait will not hang because fuse_abort_conn() ensures all requests are ended.

index 90dceb7da571..34106f6e66a0 100644
@@ -724,7 +724,7 @@ static void request_wait_answer(struct fuse_req *req)
 
 		if (req->args->abort_on_kill) {
 			fuse_chan_abort(fch, false);
-			return;
+			goto wait_for_finish;
 		}
 
 		if (test_bit(FR_URING, &req->flags))

@@ -735,6 +735,7 @@ static void request_wait_answer(struct fuse_req *req)
 			return;
 	}
 
+wait_for_finish:
 	/*
 	 * Either request is already in userspace, or it was forced.
 	 * Wait it out.

The abort_on_kill path in request_wait_answer() calls fuse_abort_conn() and returns without waiting for FR_FINISHED. If fuse_dev_do_write() is concurrently processing the same request (FR_LOCKED set), the caller frees req->args while it is still being accessed, causing a use-after-free.

Fix this by jumping to the existing wait_event(FR_FINISHED) instead of returning early. The wait will not hang because fuse_abort_conn() ensures all requests are ended.

---
 fs/fuse/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 5aea3f4d3030..878b60e15eaf 100644
@@ -580,7 +580,7 @@ static void request_wait_answer(struct fuse_req *req)
 
 		if (req->args->abort_on_kill) {
 			fuse_abort_conn(fc);
-			return;
+			goto wait_for_finish;
 		}
 
 		if (test_bit(FR_URING, &req->flags))

@@ -591,6 +591,7 @@ static void request_wait_answer(struct fuse_req *req)
 			return;
 	}
 
+wait_for_finish:
 	/*
 	 * Either request is already in userspace, or it was forced.
 	 * Wait it out.

2.45.2

7.1.y is EOL, so I've queued your patch for 6.18 instead (it applies there unchanged); 7.2 already carries the fix. Thanks.

Thanks,
Sasha