From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0123B4F7CA6; Tue, 13 Oct 2026 12:19:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893991; cv=none; b=HkHO4Y6lgVqk7JnoZ2GtCl37PrVzs0YNbjAXZdCNn/ZhTKU+jDZu3QTX20GkOo7tlOm/zwUgge5PHs4WSAPXpp+vg0lc3qn6OGnSIaHy8KQhP/wRuj7+IWjSv1UQ3utrFWfNfTRE0NhvVOtZdEwryxJkUQCmzHgfAqzpcIVUP3w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893991; c=relaxed/simple; bh=HUjTvAp60i17InNz65RJus19/qyCLuWLUlfeBey2IBk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dRDZS2rRQechGkxlG9eFf9HmTETMAaMIdNbf+Px6ZdjymIEh3bjOiwAC5grTpfKfzMGumoynQNgo1Av9U+IUqlU0/EWHSaeqDhyF7SfcuRqJYGNLUe9L4dwyqn3AuTwr/RHoFeivHP03DNR+eCicNnwMtuGVG9Pam0hJmsSY+Ik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CfdcNc3b; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CfdcNc3b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E02F1F000FF; Tue, 13 Oct 2026 12:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893989; bh=3FAFUVTKecrjjRSR5R4jo1nJhXq8fhRj6YHgkJmVudY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CfdcNc3bU2CyAPApGvqw4tiMqhhSefXJMH/vQPBU1NZNsBB8ZMe7gu6PogrCcbjo2 7mxIt6N1/i6ZFoeqCEzgTR2b3ubJharNw749fTNB8c3uBn663ssVglSpfckWxS9y1K cgNQvFx8s/ii6RB6VdGt9wSDKS8OM7stvGusn21s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kyenghwan Hwang , ChenXiaoSong , Namjae Jeon , Sasha Levin Subject: [PATCH 6.18 410/621] ksmbd: detach blocked lock requests before freeing Date: Tue, 13 Oct 2026 13:36:45 +0200 Message-ID: <20261013112930.567573674@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Namjae Jeon [ Upstream commit 215e8816b1ac25176d911abb8704390413ccee4b ] A file_lock retained by ksmbd for byte-range lock bookkeeping can still be part of the VFS blocked-request graph. In particular, the VFS can chain a new waiter below an already blocked request through flc_blocked_requests. The ksmbd_file reference count does not cover that graph. Both __ksmbd_close_fd() and the cross-request unlock path free these retained file_lock objects directly. If a dependent waiter is still attached, locks_release_private() hits BUG_ON(!list_empty(&flc->flc_blocked_requests)). The same lifetime mismatch can leave a freed ksmbd_lock reachable through its request-local llist. Detach the file_lock from the blocked-request graph before freeing it in the close, cross-request unlock, and rollback paths. locks_delete_block() also wakes requests chained below the object. Remove llist when a completed lock is published so a globally visible ksmbd_lock no longer points into the submitting worker's stack. Fixes: d63528eb0d43 ("ksmbd: free ksmbd_lock when file is closed") Reported-by: Kyenghwan Hwang Tested-by: Kyenghwan Hwang Tested-by: ChenXiaoSong Reviewed-by: ChenXiaoSong Signed-off-by: Namjae Jeon Signed-off-by: Sasha Levin --- fs/smb/server/smb2pdu.c | 14 ++++++++++---- fs/smb/server/vfs_cache.c | 8 +++++--- 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 944e33ab87ea8..5e303942a7510 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7556,6 +7556,12 @@ static void smb2_remove_blocked_lock(void **argv) locks_wake_up(flock); } +static void smb2_free_lock(struct file_lock *flock) +{ + ksmbd_vfs_posix_lock_unblock(flock); + locks_free_lock(flock); +} + static inline bool lock_defer_pending(struct file_lock *fl) { /* check pending lock waiters */ @@ -7709,14 +7715,14 @@ int smb2_lock(struct ksmbd_work *work) cmp_lock->end == smb_lock->end && !lock_defer_pending(cmp_lock->fl)) { nolock = 0; - list_del(&cmp_lock->flist); - list_del(&cmp_lock->clist); + list_del_init(&cmp_lock->flist); + list_del_init(&cmp_lock->clist); cmp_lock->conn = NULL; spin_unlock(&conn->llist_lock); up_read(&conn_list_lock); ksmbd_conn_put(conn); - locks_free_lock(cmp_lock->fl); + smb2_free_lock(cmp_lock->fl); kfree(cmp_lock); goto out_check_cl; } @@ -7914,7 +7920,7 @@ int smb2_lock(struct ksmbd_work *work) spin_unlock(&conn->llist_lock); ksmbd_conn_put(conn); - locks_free_lock(smb_lock->fl); + smb2_free_lock(smb_lock->fl); if (rlock) locks_free_lock(rlock); kfree(smb_lock); diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index ce6e9886df8be..970b8f185aacd 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -388,8 +388,9 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp) if (!IS_ERR_OR_NULL(filp)) fput(filp); - /* because the reference count of fp is 0, it is guaranteed that - * there are not accesses to fp->lock_list. + /* + * The zero fp reference count serializes access to fp->lock_list, but + * the VFS may still have blocked requests chained below these locks. */ list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) { struct ksmbd_conn *conn = smb_lock->conn; @@ -402,7 +403,8 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp) ksmbd_conn_put(conn); } - list_del(&smb_lock->flist); + list_del_init(&smb_lock->flist); + ksmbd_vfs_posix_lock_unblock(smb_lock->fl); locks_free_lock(smb_lock->fl); kfree(smb_lock); } -- 2.53.0