Re: Fwd: Re: UML kernel crash of v2.6.36-rcX kernel

From: richard -rw- weinberger
Date: Mon Oct 18 2010 - 05:31:38 EST


2010/10/18 Toralf Förster <toralf.foerster@xxxxxx>:
> Well, in addition to my last mail the following patch isn't a fix, but it
> might point to the culprit.
> If I apply this patch against latest tree, then the crash doesn't occur :
>
> diff --git a/include/linux/statfs.h b/include/linux/statfs.h
> index 0166d32..e336e70 100644
> --- a/include/linux/statfs.h
> +++ b/include/linux/statfs.h
> @@ -15,8 +15,8 @@ struct kstatfs {
>        __kernel_fsid_t f_fsid;
>        long f_namelen;
>        long f_frsize;
> -   long f_flags;
>        long f_spare[4];
> + long f_flags;
>  };
>
>
>
> Christoph Hellwig wrote at 22:18:37
>> On Sun, Oct 17, 2010 at 03:55:39PM +0200, Toralf F?rster wrote:
>> > I bisected it again w/ a fixed test script, got the same bad commit
>> > script and double checked, that this commit is really the culprit which
>> > crashes a user mode linux kernel at my 32bix x86 stable Gentoo running
>> > 2.6.35.6 vanilla kernel as host system and 2/ gcc version 4.4.3 (Gentoo
>> > 4.4.3-r2 p1.2) and glibc-2.11.2-r1 in the tool chain.
>>
>> I really can't see any relation to the patch.  Can you try the some
>> things in the following order, please:
>>
>>  (1) git-revert 365b18189789bfa1acd9939e6312b8a4b4577b28 on current
>>      Linus tree and see it it works.
>>      If it works try the next, else the bisect must have been a weird
>>      conicidence and I can't really help more.
>>  (2) re-apply only the changes to include/asm-generic/statfs.h from
>>      365b18189789bfa1acd9939e6312b8a4b4577b28 and see if that still
>>      boots.
>>  (3) re-apply the arch/mips/include/asm/statfs.h and
>>      arch/s390/include/asm/statfs.h changes and see if it still boots
>>  (4) re-apply the include/linux/statfs.h changes and see if it still
>>       boots
>>  (5) re-apply the fs/statfs.c changes, and by now it really shouldn't
>>      boot anymore
>>  (6) verify the code really is the same again as in current Linus' tree
>
>
> --
> MfG/Kind regards
> Toralf Förster
>
> pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
>
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>

Does this help?

--- linux-2.6.36-rc8/fs/hostfs/hostfs_user.c.orig 2010-10-18
11:24:33.844592000 +0200
+++ linux-2.6.36-rc8/fs/hostfs/hostfs_user.c 2010-10-18
11:24:44.594679000 +0200
@@ -388,6 +388,6 @@
spare_out[1] = buf.f_spare[1];
spare_out[2] = buf.f_spare[2];
spare_out[3] = buf.f_spare[3];
- spare_out[4] = buf.f_spare[4];
+
return 0;
}

--
Thanks,
//richard
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