On Mon, Mar 16, 2015 at 05:05:53AM -0700, tip-bot for Denys Vlasenko wrote:
> Commit-ID: 245214a155c711764b3853189441c9f8aeb058b3
> Gitweb: http://git.kernel.org/tip/245214a155c711764b3853189441c9f8aeb058b3
> Author: Denys Vlasenko <[email protected]>
> AuthorDate: Tue, 10 Mar 2015 11:45:07 +0100
> Committer: Ingo Molnar <[email protected]>
> CommitDate: Tue, 10 Mar 2015 13:56:11 +0100
>
> x86/asm/entry/64: Remove unused thread_struct::usersp
>
> All manipulations of PER_CPU(old_rsp) in C code are removed:
> it is not used on SYSRET return, so storing anything there is
> pointless.
>
> This also allows us to get rid of thread_struct::usersp,
> which was needed only to set PER_CPU(old_rsp) for correct
> return from fork/clone.
>
> Tweak a few comments as well: we no longer have "partial stack frame",
> ever.
>
> Signed-off-by: Denys Vlasenko <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: Frederic Weisbecker <[email protected]>
> Cc: H. Peter Anvin <[email protected]>
> Cc: Kees Cook <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> Cc: Oleg Nesterov <[email protected]>
> Cc: Steven Rostedt <[email protected]>
> Cc: Will Drewry <[email protected]>
> Link:
> http://lkml.kernel.org/r/[email protected]
> Signed-off-by: Ingo Molnar <[email protected]>
So this patch is causing all kinds of segfaults when booting my kvm
guest here, see below.
Reverting it makes the segfaults go away but from looking at the patch,
I have no idea why it would even cause those segfaults.
[ 5.285547] kmod[1316]: segfault at 738c08 ip 0000000000738c08 sp
00007ffdb6079c68 error 15
[ 9.537606] tput[2716]: segfault at 0 ip (null) sp
00007fffffffdbd0 error 14 in tput[400000+3000]
^^^^^^^^^^^^^^^^^
Looks like rIP has went off somewhere in the weeds.
Hmmm...
[ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp
00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000]
[ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp
00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000]
[ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp
00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000]
[ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp
00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000]
[ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp
00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000]
[ 4.593374] grep[998]: segfault at 7ffc3a9f4378 ip 00007fb8409fe1df sp
00007ffc3a9f4378 error 4 in ld-2.13.so[7fb8409e8000+20000]
[ 7.160423] sed[1999]: segfault at 7ffe9998f778 ip 00007f37deef0b52 sp
00007ffe9998f778 error 4 in libc-2.13.so[7f37dee18000+182000]
[ 5.607611] sed[1350]: segfault at 7ffddd4a4bf0 ip 00007ff24a11fafc sp
00007ffddd4a4bf0 error 4 in libc-2.13.so[7ff24a050000+182000]
[ 9.820987] update-exim4.co[2755]: segfault at 7ffff79ab000 ip
00007ffff79ab000 sp 00007fffffffe278 error 15
[ 10.580362] tput[3060]: segfault at 7ffff6376cb0 ip 00007ffff7df3422 sp
00007ffff6376cb0 error 4 in ld-2.13.so[7ffff7ddd000+20000]
[ 5.607611] sed[1350]: segfault at 7ffddd4a4bf0 ip 00007ff24a11fafc sp
00007ffddd4a4bf0 error 4 in libc-2.13.so[7ff24a050000+182000]
[ 9.820987] update-exim4.co[2755]: segfault at 7ffff79ab000 ip
00007ffff79ab000 sp 00007fffffffe278 error 15
[ 10.580362] tput[3060]: segfault at 7ffff6376cb0 ip 00007ffff7df3422 sp
00007ffff6376cb0 error 4 in ld-2.13.so[7ffff7ddd000+20000]
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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