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From: Srinivasa DS <srinivasa@in.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	        Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: ananth@in.ibm.com, Jim Keniston <jkenisto@us.ibm.com>,
	        srikar@linux.vnet.ibm.com,
	SystemTAP <systemtap@sources.redhat.com>
Subject: [BUG] Kprobes fails on 2.6.25-rc3-mm1 (x86) systems, if CONFIG_DEBUG_RODATA is set.
Date: Thu, 06 Mar 2008 12:42:00 -0000	[thread overview]
Message-ID: <200803061811.27555.srinivasa@in.ibm.com> (raw)

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
 



             reply	other threads:[~2008-03-06 12:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-06 12:42 Srinivasa DS [this message]
2008-03-06 12:56 ` Mathieu Desnoyers
2008-03-06 13:34   ` Srinivasa DS
2008-03-06 13:54     ` [PATCH] x86 - Enhance DEBUG_RODATA support - alternatives Mathieu Desnoyers
2008-03-06 14:02       ` Ingo Molnar
2008-03-06 14:24         ` Mathieu Desnoyers
2008-03-06 15:04         ` pageexec
2008-03-06 15:54           ` Ingo Molnar
2008-03-06 16:20           ` Andi Kleen
2008-03-06 17:30           ` Mathieu Desnoyers
2008-03-11 12:15             ` Andi Kleen

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