c012fba75a
commit 807252f028c59b9a3bac4d62ad84761548c10f11 upstream.
Running smb2.rename test from Samba smbtorture suite against a kernel built
with lockdep triggers a "possible recursive locking detected" warning.
This is because mnt_want_write() is called twice with no mnt_drop_write()
in between:
-> ksmbd_vfs_mkdir()
-> ksmbd_vfs_kern_path_create()
-> kern_path_create()
-> filename_create()
-> mnt_want_write()
-> mnt_want_write()
Fix this by removing the mnt_want_write/mnt_drop_write calls from vfs
helpers that call kern_path_create().
Full lockdep trace below:
============================================
WARNING: possible recursive locking detected
6.6.0-rc5 #775 Not tainted
--------------------------------------------
kworker/1:1/32 is trying to acquire lock:
ffff888005ac83f8 (sb_writers#5){.+.+}-{0:0}, at: ksmbd_vfs_mkdir+0xe1/0x410
but task is already holding lock:
ffff888005ac83f8 (sb_writers#5){.+.+}-{0:0}, at: filename_create+0xb6/0x260
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(sb_writers#5);
lock(sb_writers#5);
*** DEADLOCK ***
May be due to missing lock nesting notation
4 locks held by kworker/1:1/32:
#0: ffff8880064e4138 ((wq_completion)ksmbd-io){+.+.}-{0:0}, at: process_one_work+0x40e/0x980
#1: ffff888005b0fdd0 ((work_completion)(&work->work)){+.+.}-{0:0}, at: process_one_work+0x40e/0x980
#2: ffff888005ac83f8 (sb_writers#5){.+.+}-{0:0}, at: filename_create+0xb6/0x260
#3: ffff8880057ce760 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x123/0x260
Cc: stable@vger.kernel.org
Fixes: 40b268d384a2 ("ksmbd: add mnt_want_write to ksmbd vfs functions")
Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
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