linux-kernel - Re: frequent lockups in 3.18rc4

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Mon, 1 Dec 2014 18:08:38 -0500
From:	Chris Mason <clm@...com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Dâniel Fraga <fragabr@...il.com>,
	Dave Jones <davej@...hat.com>,
	Sasha Levin <sasha.levin@...cle.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: frequent lockups in 3.18rc4

I'm not sure if this is related, but running trinity here, I noticed it
was stuck at 100% system time on every CPU.  perf report tells me we are
spending all of our time in spin_lock under the sync system call.

I think it's coming from contention in the bdi_queue_work() call from
inside sync_inodes_sb, which is spin_lock_bh(). 

I wonder if we're just spinning so hard on this one bh lock that we're
starving the watchdog?

Dave, do you have spinlock debugging on?  

-chris
--
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/