Re: shm broken on MIPS in current -git

From: Vasiliy Kulikov
Date: Mon Aug 01 2011 - 09:11:52 EST


Hi Manuel,

On Mon, Aug 01, 2011 at 14:51 +0200, Manuel Lauss wrote:
> Commits 5774ed014f02120db9a6945a1ecebeb97c2acccb
> (shm: handle separate PID namespaces case)
> and 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d
> (shm: optimize locking and ipc_namespace getting)
> break on my MIPS systems.

Can you please identify what commit breaks the system?

> The following oops is
> printed on boot, and as a result, more than 300 zombie kworker
> kernel processes are resident. I don't see this oops on x86 or x64.

Do you have the same configs for x86 and mips?

> ra points to the down_write() in ipc/shm.c::exit_shm()
>
> CPU 0 Unable to handle kernel paging request at virtual address
> 00000000, epc == 80527c64, ra == 8024afb8
> Oops[#1]:
> Cpu 0
> $ 0 : 00000000 10003c00 00000000 10003c01
> $ 4 : 8060d114 8fc45e60 8060d118 8fc3f520
> $ 8 : 00000000 01312d00 0016e35f 00020000
> $12 : 00000080 00000010 00000010 8fc3001c
> $16 : 8fc3f520 00000000 00000000 00000000
> $20 : 00000000 00000000 8fc45eb4 00000000
> $24 : 00000000 8011f9b0
> $28 : 8fc44000 8fc45e50 00000001 8024afb8
> Hi : 00000000
> Lo : 01312d00
> epc : 80527c64 __down_write_nested+0x68/0xf0
> Not tainted
> ra : 8024afb8 exit_shm+0x30/0x64
> Status: 10003c02 KERNEL EXL
> Cause : 0080800c
> BadVA : 00000000
> PrId : 800c8000 (Au1300)
> Process kworker/u:0 (pid: 9, threadinfo=8fc44000, task=8fc3f520, tls=00000000)
> Stack : 14200972 d3054429 00000000 56b8e493 8060d118 00000000 8fc3f520 00000002
> 8fc2c000 8060d114 00000000 8024afb8 00000000 00000000 00000000 00000000
> 8060d0c0 00000000 8fc3f520 80128ae8 30480023 0b309f84 34ffeedb ef9e65d6
> 38019941 af430015 f6d9ebeb 00000000 00000000 00000000 8fc29ce0 8fc15300
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 80139578
> ...
> Call Trace:
> [<80527c64>] __down_write_nested+0x68/0xf0
> [<8024afb8>] exit_shm+0x30/0x64
> [<80128ae8>] do_exit+0x50c/0x664
> [<80139578>] ____call_usermodehelper+0xfc/0x118
> [<801061bc>] kernel_thread_helper+0x10/0x18
>
>
> Code: ac850008 afa60010 afa20014 <ac450000> 40016000 30630001
> 3421001f 3821001f 00611825
> Disabling lock debugging due to kernel taint
> Fixing recursive fault but reboot is needed!
>
>
> Thanks,
> Manuel Lauss

--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
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