FAILED: patch "[PATCH] ksmbd: call ksmbd_vfs_kern_path_end_removing() on some error" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-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-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x a09dc10d1353f0e92c21eae2a79af1c2b1ddcde8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026022442-gecko-tux-0fc5@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From a09dc10d1353f0e92c21eae2a79af1c2b1ddcde8 Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <[email protected]>
Date: Sat, 14 Feb 2026 18:45:14 +0300
Subject: [PATCH] ksmbd: call ksmbd_vfs_kern_path_end_removing() on some error
paths

There are two places where ksmbd_vfs_kern_path_end_removing() needs to be called in order to balance what the corresponding successful call to ksmbd_vfs_kern_path_start_removing() has done, i.e. drop inode locks and put the taken references. Otherwise there might be potential deadlocks and unbalanced locks which are caught like:

BUG: workqueue leaked lock or atomic: kworker/5:21/0x00000000/7596
     last function: handle_ksmbd_work
2 locks held by kworker/5:21/7596:
 #0: ffff8881051ae448 (sb_writers#3){.+.+}-{0:0}, at: ksmbd_vfs_kern_path_locked+0x142/0x660
 #1: ffff888130e966c0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: ksmbd_vfs_kern_path_locked+0x17d/0x660
CPU: 5 PID: 7596 Comm: kworker/5:21 Not tainted 6.1.162-00456-gc29b353f383b #138
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
Workqueue: ksmbd-io handle_ksmbd_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x44/0x5b
 process_one_work.cold+0x57/0x5c
 worker_thread+0x82/0x600
 kthread+0x153/0x190
 ret_from_fork+0x22/0x30
 </TASK>

Found by Linux Verification Center (linuxtesting.org).

index cbb31efdbaa2..2782eea214d0 100644
@@ -6115,14 +6115,14 @@ static int smb2_create_link(struct ksmbd_work *work,
 				rc = -EINVAL;
 				ksmbd_debug(SMB, "cannot delete %s\n",
 					    link_name);
-				goto out;
 			}
 		} else {
 			rc = -EEXIST;
 			ksmbd_debug(SMB, "link already exists\n");
-			goto out;
 		}
 		ksmbd_vfs_kern_path_end_removing(&path);
+		if (rc)
+			goto out;
 	}
 	rc = ksmbd_vfs_link(work, target_name, link_name);
 	if (rc)

From: Fedor Pchelkin <[email protected]>

[ Upstream commit a09dc10d1353f0e92c21eae2a79af1c2b1ddcde8 ]

There are two places where ksmbd_vfs_kern_path_end_removing() needs to be called in order to balance what the corresponding successful call to ksmbd_vfs_kern_path_start_removing() has done, i.e. drop inode locks and put the taken references. Otherwise there might be potential deadlocks and unbalanced locks which are caught like:

BUG: workqueue leaked lock or atomic: kworker/5:21/0x00000000/7596
     last function: handle_ksmbd_work
2 locks held by kworker/5:21/7596:
 #0: ffff8881051ae448 (sb_writers#3){.+.+}-{0:0}, at: ksmbd_vfs_kern_path_locked+0x142/0x660
 #1: ffff888130e966c0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: ksmbd_vfs_kern_path_locked+0x17d/0x660
CPU: 5 PID: 7596 Comm: kworker/5:21 Not tainted 6.1.162-00456-gc29b353f383b #138
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
Workqueue: ksmbd-io handle_ksmbd_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x44/0x5b
 process_one_work.cold+0x57/0x5c
 worker_thread+0x82/0x600
 kthread+0x153/0x190
 ret_from_fork+0x22/0x30
 </TASK>

Found by Linux Verification Center (linuxtesting.org).

---
 fs/smb/server/smb2pdu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index da4d914c87ad2..27cc74b63b553 100644
@@ -6067,14 +6067,14 @@ static int smb2_create_link(struct ksmbd_work *work,
 				rc = -EINVAL;
 				ksmbd_debug(SMB, "cannot delete %s\n",
 					    link_name);
-				goto out;
 			}
 		} else {
 			rc = -EEXIST;
 			ksmbd_debug(SMB, "link already exists\n");
-			goto out;
 		}
 		ksmbd_vfs_kern_path_unlock(&parent_path, &path);
+		if (rc)
+			goto out;
 	}
 	rc = ksmbd_vfs_link(work, target_name, link_name);
 	if (rc)

2.51.0