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Re: [BUG] Kprobes fails on 2.6.25-rc3-mm1 (x86) systems, if CONFIG_DEBUG_RODATA is set.
- From: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
- To: Srinivasa DS <srinivasa at in dot ibm dot com>
- Cc: Andrew Morton <akpm at linux-foundation dot org>, linux-kernel at vger dot kernel dot org, ananth at in dot ibm dot com, Jim Keniston <jkenisto at us dot ibm dot com>, srikar at linux dot vnet dot ibm dot com, SystemTAP <systemtap at sources dot redhat dot com>
- Date: Thu, 6 Mar 2008 07:55:51 -0500
- Subject: Re: [BUG] Kprobes fails on 2.6.25-rc3-mm1 (x86) systems, if CONFIG_DEBUG_RODATA is set.
- References: <200803061811.27555.srinivasa@in.ibm.com>
* Srinivasa DS (srinivasa@in.ibm.com) wrote:
> Insertion of kprobe module causes oops on 2.6.25-rc3-mm1 (x86) systems if we
> enable CONFIG_DEBUG_RODATA. While registering the probe, memcpy() fails to
> copy breakpoint instruction to the instruction address and generates the
> oops.
>
> BUG: unable to handle kernel paging request at ffffffff8047d1a7
> IP: [<ffffffff8047ff62>] text_poke+0xa/0x10
> PGD 203067 PUD 207063 PMD 7e191163 PTE 47d161
> Oops: 0003 [1] PREEMPT SMP
> ................................................
>
> This is because, Mathieu's patch (http://lkml.org/lkml/2008/2/2/226) makes
> entire text segment as READONLY, if we enable CONFIG_DEBUG_RODATA.
>
> So reverting this patch or new patch, which considers kprobes while deciding
> boundary for setting readonly pages might solve the probelm.
>
Hi,
Are you running under Xen, lguest, kvm.. ?
Mathieu
> Thanks
> Srinivasa DS
> LTC-IBM
>
>
>
>
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68