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Re: futex and soft lockup
- From: AmÃrico Wang <xiyou dot wangcong at gmail dot com>
- To: Gong Cheng <chengg11 at yahoo dot com>
- Cc: libc-help at sourceware dot org
- Date: Tue, 20 Oct 2009 17:35:16 +0800
- Subject: Re: futex and soft lockup
- References: <983966.71700.qm@web82107.mail.mud.yahoo.com>
On Tue, Oct 20, 2009 at 4:55 AM, Gong Cheng <chengg11@yahoo.com> wrote:
> Hi,
> Â ÂI am running glibc-2.5-34.x86_64.rpm (for CentOS) on top of a 2.6.31 (tried 2.6.30 too) kernel, and I am consistently seeing system soft lockups like the following:
>
> BUG: soft lockup - CPU#0 stuck for 61s! [<my program>:3068]
> <snip>
> Call Trace:
> Â[<ffffffff8130e8d6>] ? _spin_lock+0x16/0x40
> Â[<ffffffff8105fe85>] ? futex_wait_setup+0x75/0x100
> Â[<ffffffff81060109>] ? futex_wait+0xf9/0x270
> Â[<ffffffff8108c80b>] ? zone_statistics+0x5b/0x90
> Â[<ffffffff810619fb>] ? do_futex+0xbb/0xcb0
> Â[<ffffffff81082f98>] ? ____pagevec_lru_add+0x138/0x150
> Â[<ffffffff810317ac>] ? update_curr+0x6c/0xc0
> Â[<ffffffff810831b1>] ? __lru_cache_add+0x71/0xb0
> Â[<ffffffff81083204>] ? lru_cache_add_lru+0x14/0x30
> Â[<ffffffff8130eda1>] ? _spin_unlock+0x11/0x40
> Â[<ffffffff8108f0de>] ? do_wp_page+0x28e/0x7b0
> Â[<ffffffff81090e3a>] ? handle_mm_fault+0x59a/0x7c0
> Â[<ffffffff8130ea12>] ? _spin_lock_irqsave+0x22/0x50
> Â[<ffffffff8130ee63>] ? _spin_unlock_irqrestore+0x13/0x40
> Â[<ffffffff81062680>] ? sys_futex+0x90/0x150
> Â[<ffffffff81029417>] ? do_page_fault+0x187/0x2d0
> Â[<ffffffff8100bceb>] ? system_call_fastpath+0x16/0x1b
>
> previously when running glibc-2.5.18 I didn't have this problem. In fact, if I switch back to 2.5.18 while keeping everything else Âthe same, the problem immediately stops.
>
> My program uses pthread and futex extensively. If I run the program in single-threaded mode, then I don't have the issue.
>
> I am aware I am not providing a lot of information here, but just want to quickly check if this issue is known to anyone here?
> Also in general, is it a bad idea to combine 2.5-34 glibc with the latest kernel?
>
> I'd appreciate any tips on this issue!
This is more than a kernel problem. :)
Kernel is not supposed to have a 'soft lockup' no matter how you use futex in
user-space. Would mind to try the latest git kernel with glibc-2.5-34?
Thanks.