linux-kernel - Re: RCU hang on cpu re-hotplug with 2.6.27rc8

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]

Message-ID: <20081007071544.GC20740@one.firstfloor.org>
Date:	Tue, 7 Oct 2008 09:15:44 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	Andi Kleen <andi@...stfloor.org>, mingo@...e.hu,
	linux-kernel@...r.kernel.org, rjw@...k.pl, dipankar@...ibm.com,
	tglx@...uxtronix.de
Subject: Re: RCU hang on cpu re-hotplug with 2.6.27rc8

> Could you please try the patch at the following URL (from Thomas
> Gleixner)?
> 
> http://www.rdrop.com/users/paulmck/patches/2.6.27-rc7-tglx-timer-1.patch
> 
> This fixed some CPU hotplug hangs that I was seeing in 2.6.27-rc7 and
> -rc8.  Alternatively, try 2.6.27-rc9, which seems to include Thomas's
> patch.

Still happens with rc9.  This time with frame pointers:

bash          D 00000000ffff975e     0  4770   4757
 ffff8804bcda3bf8 0000000000000082 ffff8804bcda3c18 0000000000000296
 ffff8804bde4e6b0 ffff8804be6fc630 ffff8804bde4e8f8 0000000e00000296
 ffff8804bcda3c18 ffffffff808cfd98 ffff880288064780 ffff88027d18ec98
Call Trace:
 [<ffffffff805c4915>] schedule_timeout+0x22/0xb4
 [<ffffffff8020a009>] ? __switch_to+0x320/0x330
 [<ffffffff802602ed>] ? cpupri_set+0xc5/0xd8
 [<ffffffff805c476f>] wait_for_common+0xcd/0x131
 [<ffffffff8022db87>] ? default_wake_function+0x0/0xf
 [<ffffffff805c485d>] wait_for_completion+0x18/0x1a
 [<ffffffff80243fbf>] synchronize_rcu+0x35/0x3c
 [<ffffffff8024403e>] ? wakeme_after_rcu+0x0/0x12
 [<ffffffff8022ed25>] partition_sched_domains+0x9b/0x1dd
 [<ffffffff8022dbb3>] ? wake_up_process+0x10/0x12
 [<ffffffff8022ee95>] update_sched_domains+0x2e/0x35
 [<ffffffff805c8342>] notifier_call_chain+0x33/0x5b
 [<ffffffff80249291>] __raw_notifier_call_chain+0x9/0xb
 [<ffffffff802492a2>] raw_notifier_call_chain+0xf/0x11
 [<ffffffff805c1c3a>] _cpu_up+0xd3/0x10c
 [<ffffffff805c1cca>] cpu_up+0x57/0x67
 [<ffffffff805a5787>] store_online+0x4d/0x75
 [<ffffffff803e67bb>] sysdev_store+0x1b/0x1d
 [<ffffffff802cce10>] sysfs_write_file+0xe0/0x11c
 [<ffffffff8028b661>] vfs_write+0xae/0x137
 [<ffffffff8028bb0a>] sys_write+0x47/0x6f
 [<ffffffff8020b34b>] system_call_fastpath+0x16/0x1b

BTW it also happens reliably every time. Reproduced it three times
now. I just do

laut:~ # echo 0 > /sys/devices/system/cpu/cpu15/online 
laut:~ # echo 0 > /sys/devices/system/cpu/cpu14/online 
laut:~ # echo 1 > /sys/devices/system/cpu/cpu14/online 
laut:~ # echo 1 > /sys/devices/system/cpu/cpu15/online 
<hang>

-Andi

--
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/