From: "Theodore Ts'o" <tytso@mit.edu>
To: Tahsin Erdogan <tahsin@google.com>
Cc: Andreas Dilger <adilger@dilger.ca>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
Jan Kara <jack@suse.cz>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/32] ext4: fix lockdep warning about recursive inode locking
Date: Wed, 21 Jun 2017 21:18:34 -0400 [thread overview]
Message-ID: <20170622011834.kvbsjvcpit233n5d@thunk.org> (raw)
In-Reply-To: <20170621212142.16581-2-tahsin@google.com>
On Wed, Jun 21, 2017 at 02:21:12PM -0700, Tahsin Erdogan wrote:
> Setting a large xattr value may require writing the attribute contents
> to an external inode. In this case we may need to lock the xattr inode
> along with the parent inode. This doesn't pose a deadlock risk because
> xattr inodes are not directly visible to the user and their access is
> restricted.
>
> Assign a lockdep subclass to xattr inode's lock.
>
> ============================================
> WARNING: possible recursive locking detected
> 4.12.0-rc1+ #740 Not tainted
> --------------------------------------------
> python/1822 is trying to acquire lock:
> (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff804912ca>] ext4_xattr_set_entry+0x65a/0x7b0
>
> but task is already holding lock:
> (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&sb->s_type->i_mutex_key#15);
> lock(&sb->s_type->i_mutex_key#15);
>
> *** DEADLOCK ***
>
> May be due to missing lock nesting notation
>
> 4 locks held by python/1822:
> #0: (sb_writers#10){.+.+.+}, at: [<ffffffff803d0eef>] mnt_want_write+0x1f/0x50
> #1: (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0
> #2: (jbd2_handle){.+.+..}, at: [<ffffffff80493f40>] start_this_handle+0xf0/0x420
> #3: (&ei->xattr_sem){++++..}, at: [<ffffffff804920ba>] ext4_xattr_set_handle+0x9a/0x4f0
>
> stack backtrace:
> CPU: 0 PID: 1822 Comm: python Not tainted 4.12.0-rc1+ #740
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
> dump_stack+0x67/0x9e
> __lock_acquire+0x5f3/0x1750
> lock_acquire+0xb5/0x1d0
> down_write+0x2c/0x60
> ext4_xattr_set_entry+0x65a/0x7b0
> ext4_xattr_block_set+0x1b2/0x9b0
> ext4_xattr_set_handle+0x322/0x4f0
> ext4_xattr_set+0x144/0x1a0
> ext4_xattr_user_set+0x34/0x40
> __vfs_setxattr+0x66/0x80
> __vfs_setxattr_noperm+0x69/0x1c0
> vfs_setxattr+0xa2/0xb0
> setxattr+0x12e/0x150
> path_setxattr+0x87/0xb0
> SyS_setxattr+0xf/0x20
> entry_SYSCALL_64_fastpath+0x18/0xad
>
> Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Thanks, applied.
- Ted
next prev parent reply other threads:[~2017-06-22 1:18 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 21:21 [PATCH 01/32] ext4: xattr-in-inode support Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 02/32] ext4: fix lockdep warning about recursive inode locking Tahsin Erdogan
2017-06-22 1:18 ` Theodore Ts'o [this message]
2017-06-21 21:21 ` [PATCH 03/32] ext4: lock inode before calling ext4_orphan_add() Tahsin Erdogan
2017-06-22 1:20 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 04/32] ext4: do not set posix acls on xattr inodes Tahsin Erdogan
2017-06-22 1:23 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 05/32] ext4: attach jinode after creation of xattr inode Tahsin Erdogan
2017-06-22 1:26 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 06/32] ext4: ea_inode owner should be the same as the inode owner Tahsin Erdogan
2017-06-22 1:28 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 07/32] ext4: call journal revoke when freeing ea_inode blocks Tahsin Erdogan
2017-06-22 1:38 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 08/32] ext4: fix ref counting for ea_inode Tahsin Erdogan
2017-06-22 1:40 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 09/32] ext4: extended attribute value size limit is enforced by vfs Tahsin Erdogan
2017-06-22 1:42 ` Theodore Ts'o
2017-06-22 18:02 ` Darrick J. Wong
2017-06-22 19:40 ` Andreas Dilger
2017-06-22 22:27 ` Theodore Ts'o
2017-06-22 23:21 ` Darrick J. Wong
2017-06-21 21:21 ` [PATCH 10/32] ext4: change ext4_xattr_inode_iget() signature Tahsin Erdogan
2017-06-22 1:55 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 11/32] ext4: clean up ext4_xattr_inode_get() Tahsin Erdogan
2017-06-22 1:58 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 12/32] ext4: add missing le32_to_cpu(e_value_inum) conversions Tahsin Erdogan
2017-06-22 2:00 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 13/32] ext4: ext4_xattr_value_same() should return false for external data Tahsin Erdogan
2017-06-22 2:04 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 14/32] ext4: fix ext4_xattr_make_inode_space() value size calculation Tahsin Erdogan
2017-06-22 2:09 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 15/32] ext4: fix ext4_xattr_move_to_block() Tahsin Erdogan
2017-06-22 2:13 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 16/32] ext4: fix ext4_xattr_cmp() Tahsin Erdogan
2017-06-22 2:15 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 17/32] ext4: fix credits calculation for xattr inode Tahsin Erdogan
2017-06-22 2:19 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 18/32] ext4: retry storing value in external inode with xattr block too Tahsin Erdogan
2017-06-22 2:22 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 19/32] ext4: ext4_xattr_delete_inode() should return accurate errors Tahsin Erdogan
2017-06-22 2:27 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 20/32] ext4: improve journal credit handling in set xattr paths Tahsin Erdogan
2017-06-22 2:30 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 21/32] ext4: modify ext4_xattr_ino_array to hold struct inode * Tahsin Erdogan
2017-06-22 14:28 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 22/32] ext4: move struct ext4_xattr_inode_array to xattr.h Tahsin Erdogan
2017-06-22 14:29 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 23/32] mbcache: make mbcache naming more generic Tahsin Erdogan
2017-06-22 14:37 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 24/32] ext2, ext4: make mb block cache names more explicit Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 25/32] ext4: add ext4_is_quota_file() Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 26/32] ext4: cleanup transaction restarts during inode deletion Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 27/32] ext4: xattr inode deduplication Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 28/32] quota: add get_inode_usage callback to transfer multi-inode charges Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 29/32] ext4: reserve space for xattr entries/names Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 30/32] ext4: eliminate xattr entry e_hash recalculation for removes Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 31/32] ext4: strong binding of xattr inode references Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 32/32] ext4: add nombcache mount option Tahsin Erdogan
2017-06-22 1:16 ` [PATCH 01/32] ext4: xattr-in-inode support Theodore Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170622011834.kvbsjvcpit233n5d@thunk.org \
--to=tytso@mit.edu \
--cc=adilger@dilger.ca \
--cc=darrick.wong@oracle.com \
--cc=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tahsin@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).