From a82c92bcfc058bb1787deff7c1cc615923275633 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@kernel.org>
Date: Mon, 1 Jun 2026 15:56:47 +0200
Subject: [PATCH] ksmbd: use scoped_with_init_fs() for filesystem info path
 lookup
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Use scoped_with_init_fs() to temporarily override current->fs for
the kern_path() call in smb2_get_info_filesystem() so the share
path lookup happens in init's filesystem context.

All ksmbd paths ← SMB command handlers ← handle_ksmbd_work() ← workqueue
← ksmbd_conn_handler_loop() ← kthread

Link: https://patch.msgid.link/20260601-work-kthread-nullfs-v4-14-77ee053060e0@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/smb/server/smb2pdu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 5859fa68bb84..c5d2a00c3716 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -9,6 +9,7 @@
 #include <net/addrconf.h>
 #include <linux/syscalls.h>
 #include <linux/namei.h>
+#include <linux/fs_struct.h>
 #include <linux/statfs.h>
 #include <linux/ethtool.h>
 #include <linux/falloc.h>
@@ -5867,7 +5868,8 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
 	if (!share->path)
 		return -EIO;
 
-	rc = kern_path(share->path, LOOKUP_NO_SYMLINKS, &path);
+	scoped_with_init_fs()
+		rc = kern_path(share->path, LOOKUP_NO_SYMLINKS, &path);
 	if (rc) {
 		pr_err("cannot create vfs path\n");
 		return -EIO;