From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: circular locking: /proc/sys/vm/drop_caches
Date: Fri, 23 Feb 2007 07:35:38 +0100 [thread overview]
Message-ID: <20070223063538.GA13679@elte.hu> (raw)
Andrew,
i just got the lockdep warning below when doing:
echo 3 > /proc/sys/vm/drop_caches
is this a known quirk in the drop_caches code?
Ingo
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.20-syslet #434
-------------------------------------------------------
bash/12166 is trying to acquire lock:
(&journal->j_list_lock){--..}, at: [<c01c82f5>] journal_try_to_free_buffers+0xd5/0x18f
but task is already holding lock:
(inode_lock){--..}, at: [<c01947a3>] drop_pagecache+0x45/0xc8
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (inode_lock){--..}:
[<c0144940>] __lock_acquire+0x984/0xa94
[<c0144d6f>] lock_acquire+0x67/0x8c
[<c0424a9f>] _spin_lock+0x35/0x42
[<c0193ccb>] __mark_inode_dirty+0xe3/0x15e
[<c016253b>] __set_page_dirty_nobuffers+0xb4/0xbf
[<c0197361>] mark_buffer_dirty+0x1e/0x20
[<c01c7af2>] __journal_temp_unlink_buffer+0x176/0x17d
[<c01c7d23>] __journal_unfile_buffer+0xb/0x15
[<c01c7d97>] __journal_refile_buffer+0x6a/0xe3
[<c01cac34>] journal_commit_transaction+0xf46/0x11da
[<c01cd32c>] kjournald+0xab/0x1e8
[<c013b935>] kthread+0xb2/0xd7
[<c0104e5f>] kernel_thread_helper+0x7/0x10
[<ffffffff>] 0xffffffff
-> #0 (&journal->j_list_lock){--..}:
[<c014483b>] __lock_acquire+0x87f/0xa94
[<c0144d6f>] lock_acquire+0x67/0x8c
[<c0424a9f>] _spin_lock+0x35/0x42
[<c01c82f5>] journal_try_to_free_buffers+0xd5/0x18f
[<c01b944e>] ext3_releasepage+0x68/0x74
[<c015d027>] try_to_release_page+0x33/0x44
[<c016406e>] invalidate_mapping_pages+0x69/0xca
[<c01640dc>] invalidate_inode_pages+0xd/0x11
[<c01947bf>] drop_pagecache+0x61/0xc8
[<c019485c>] drop_caches_sysctl_handler+0x36/0x4e
[<c012efdc>] do_rw_proc+0xaf/0xf1
[<c012f078>] proc_writesys+0x20/0x25
[<c017b3de>] vfs_write+0xb1/0x165
[<c017bbc6>] sys_write+0x3d/0x61
[<c01041a8>] syscall_call+0x7/0xb
[<ffffffff>] 0xffffffff
other info that might help us debug this:
2 locks held by bash/12166:
#0: (&type->s_umount_key#17){----}, at: [<c0194793>] drop_pagecache+0x35/0xc8
#1: (inode_lock){--..}, at: [<c01947a3>] drop_pagecache+0x45/0xc8
stack backtrace:
[<c010510d>] show_trace_log_lvl+0x19/0x2e
[<c0105206>] show_trace+0x12/0x14
[<c010521c>] dump_stack+0x14/0x16
[<c01433ff>] print_circular_bug_tail+0x5f/0x68
[<c014483b>] __lock_acquire+0x87f/0xa94
[<c0144d6f>] lock_acquire+0x67/0x8c
[<c0424a9f>] _spin_lock+0x35/0x42
[<c01c82f5>] journal_try_to_free_buffers+0xd5/0x18f
[<c01b944e>] ext3_releasepage+0x68/0x74
[<c015d027>] try_to_release_page+0x33/0x44
[<c016406e>] invalidate_mapping_pages+0x69/0xca
[<c01640dc>] invalidate_inode_pages+0xd/0x11
[<c01947bf>] drop_pagecache+0x61/0xc8
[<c019485c>] drop_caches_sysctl_handler+0x36/0x4e
[<c012efdc>] do_rw_proc+0xaf/0xf1
[<c012f078>] proc_writesys+0x20/0x25
[<c017b3de>] vfs_write+0xb1/0x165
[<c017bbc6>] sys_write+0x3d/0x61
[<c01041a8>] syscall_call+0x7/0xb
=======================
next reply other threads:[~2007-02-23 6:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-23 6:35 Ingo Molnar [this message]
2007-02-23 9:40 ` circular locking: /proc/sys/vm/drop_caches Frederik Deweerdt
2007-02-23 10:07 ` Andrew Morton
2007-02-23 11:36 ` Ingo Molnar
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=20070223063538.GA13679@elte.hu \
--to=mingo@elte.hu \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.