Re: Linux 2.6.26-rc1 - pgtable_32.c:178 pmd_bad

[Ingo Molnar <mingo@elte.hu>]

* Jeff Chua <jeff.chua.linux@gmail.com> wrote:

> On Sun, May 4, 2008 at 3:38 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> >  So this merge window was somewhat rocky in the sense that there was a lot
> >  of arguments about it, but at the same time I at least personally think
> >  that from a technical angle, we had somewhat less scary stuff going on
> >  than has been almost the rule lately.
> 
> I'm seeing this on a Dell 2950 (quad-core) during boot up, but not on
> my IBM X60s (dual-core). This is using the lastest git 2.6.26-rc1.
> 
> Just checking to see if this is a known bug before doing the bisect -- 
> more painful on the 2950 to reboot.

> ------------[ cut here ]------------
> WARNING: at arch/x86/mm/pgtable_32.c:178 pmd_bad+0xa3/0xe3()
> Modules linked in:
> Pid: 1226, comm: khelper Not tainted 2.6.26-rc1 #4
>  [<c0121614>] warn_on_slowpath+0x40/0x65
>  [<c011823e>] kmap_atomic+0x11/0x14
>  [<c01183b7>] kunmap_atomic+0x4f/0x78
>  [<c014a0db>] get_page_from_freelist+0x33a/0x3da
>  [<c014a225>] __alloc_pages_internal+0x98/0x356
>  [<c01181f8>] kmap_atomic_prot+0x102/0x137
>  [<c01183b7>] kunmap_atomic+0x4f/0x78
>  [<c0154dd0>] handle_mm_fault+0xb70/0xbba
>  [<c011770c>] pmd_bad+0xa3/0xe3
>  [<c0151cad>] follow_page+0x109/0x30a
>  [<c015516b>] get_user_pages+0x351/0x3c0
>  [<c016aec4>] get_arg_page+0x2b/0x7b
>  [<c016afe1>] copy_strings+0xcd/0x173
>  [<c016b0a0>] copy_strings_kernel+0x19/0x27
>  [<c016c28a>] do_execve+0xd9/0x18f
>  [<c010136a>] sys_execve+0x2a/0x4f
>  [<c0102d22>] syscall_call+0x7/0xb
>  [<c038007b>] i8042_probe+0x29f/0x508
>  [<c0106034>] kernel_execve+0x14/0x18
>  [<c012dcfc>] ____call_usermodehelper+0x0/0x105
>  [<c012ddf7>] ____call_usermodehelper+0xfb/0x105
>  [<c012dcfc>] ____call_usermodehelper+0x0/0x105
>  [<c0103917>] kernel_thread_helper+0x7/0x10

no, i have not seen this reported yet.

we have an strace/ptrace fix pending in x86.git - but that should not 
affect khelper.

	Ingo