This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
[BUG] Kprobes fails on 2.6.25-rc3-mm1 (x86) systems, if CONFIG_DEBUG_RODATA is set.
- From: Srinivasa DS <srinivasa at in dot ibm dot com>
- To: Andrew Morton <akpm at linux-foundation dot org>, linux-kernel at vger dot kernel dot org, Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
- Cc: 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 18:11:27 +0530
- Subject: [BUG] Kprobes fails on 2.6.25-rc3-mm1 (x86) systems, if CONFIG_DEBUG_RODATA is set.
- Organization: IBM
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.
Thanks
Srinivasa DS
LTC-IBM