Re: Kernel OOPS in function_graph_tracer due to the 44259b1. Moreoopses in tracing...

[Witold Baryluk]

On 05-30 16:14, Andrew Lutomirski wrote:
> On Mon, May 30, 2011 at 12:10 PM, Witold Baryluk
> <baryluk@xxxxxxxxxxxxxxxx> wrote:
> > Hi,
> >
> > I found yesterday a problem when booting system on Pentium-M, 32-bit.
> >
> > I got approximetly this
> >
> > [    2.459170] Testing tracer function_graph:
> > [    2.466979] BUG: unable to handle kernel paging request at e421cc10
> 
> >
> > Reverting commit 44259b1abfaa8bb819d25d41d71e8e33e25dd36a on top of current
> > kernel make bug disapear.
> >
> > Disabling CONFIG_FUNCTION_GRAPH_TRACER also make bug dispear.
> >
> 
> Of course, the most trivial of my patches was the one with the most
> significant bug.  Can you try this fix:
> 
> http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=89e1be50c68eb5e58b873dce87bbac627ee18d1f
> 
> --Andy

Well, to add more.

It fixed most of crashes and definietl one with function graph tracer.

However in 1/10 of boots I still got some kind of crash, oops or panic.

I repeated 50 times a boot cycle on qemu, and got oopses in attachments.

...
[    0.036201] CPU: Intel Pentium III (Katmai) stepping 03
[    0.038551] ftrace: allocating 6263 entries in 13 pages
[    0.050411] BUG: unable to handle kernel NULL pointer dereference at 00000012
[    0.051079] IP: [<c106a07f>] note_interrupt+0xf/0x1c0
[    0.051743] *pdpt = 0000000000000000 *pde = f000ff53f000ff53 
...
CRASH


....
[    0.035682] CPU: Intel Pentium III (Katmai) stepping 03
[    0.038048] ftrace: allocating 6263 entries in 13 pages
[    0.050386] BUG: unable to handle kernel paging request at 8a51553a
[    0.051031] IP: [<c10587cd>] tick_handle_periodic+0x1d/0x90
[    0.051705] *pdpt = 0000000000000000 *pde = f000ff53f000ff53 
...
CRASH

...
[    1.758224] Testing tracer preemptirqsoff: 
[    1.772287] ------------[ cut here ]------------
[    1.773193] WARNING: at kernel/lockdep.c:3351 check_flags+0x186/0x190()
...
BOOTING (up to mounting root - not tested more)

...
[    0.045767] CPU: Intel Pentium III (Katmai) stepping 03
[    0.048323] ftrace: allocating 6263 entries in 13 pages
CRASH


Details in attachments.


Regards,
Witek

-- 
Witold Baryluk

Attachment: config.txt.gz
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Attachment: oops1.txt.gz
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Attachment: oops2.txt.gz
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Attachment: oops3.txt.gz
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Attachment: oops4.txt.gz
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Attachment: oops5.txt.gz
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Attachment: oops6.txt.gz
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