linux-kernel - Re: INFO: possible circular locking dependency detected

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 19 Oct 2006 16:30:24 +1000
From:	Nick Piggin <nickpiggin@...oo.com.au>
To:	Andrew Morton <akpm@...l.org>
CC:	"alpha @ steudten Engineering" <alpha@...udten.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: INFO: possible circular locking dependency detected

Andrew Morton wrote:
> On Tue, 17 Oct 2006 00:32:44 +1000
> Nick Piggin <nickpiggin@...oo.com.au> wrote:
> 
> 
>>alpha @ steudten Engineering wrote:
>>
>>>=======================================================
>>>[ INFO: possible circular locking dependency detected ]
>>>2.6.18-1.2189self #1
>>>-------------------------------------------------------
>>>kswapd0/186 is trying to acquire lock:
>>> (&inode->i_mutex){--..}, at: [<c0326e32>] mutex_lock+0x21/0x24
>>>
>>>but task is already holding lock:
>>> (iprune_mutex){--..}, at: [<c0326e32>] mutex_lock+0x21/0x24
>>>
>>>which lock already depends on the new lock.
>>
>>Thanks. __grab_cache_page wants to clear __GFP_FS, because it is
>>holding the i_mutex so we don't want to reenter the filesystem in
>>page reclaim.
> 
> 
> We want to be able to enter page reclaim while holding i_mutex.  Think what
> the effect of not doing this would be upon write() (!)
> 
> This warning is more fallout from ntfs's insistence on taking i_mutex in
> its clear_inode().  See lengthy and unproductive discussion at
> http://lkml.org/lkml/2006/7/26/185 .

Yeah you're right. It will be a hot allocation + reclaim path for high
bandwidth writes.

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/