* [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes)
@ 2007-07-25 13:01 Srinivasa Ds
2007-07-25 15:22 ` S. P. Prasanna
0 siblings, 1 reply; 3+ messages in thread
From: Srinivasa Ds @ 2007-07-25 13:01 UTC (permalink / raw)
To: linux-kernel, Andrew Morton, ananth, prasanna,
anil.s.keshavamurthy, jkenisto, systemtap
Cc: suzuki
When I was testing kprobes on x86_64 and I come across the below error message
on latest 2.6.23-rc1 kernel.
==========================================
Trying to vfree() bad address (ffffc20002233199)
WARNING: at mm/vmalloc.c:330 __vunmap()
Call Trace:
[<ffffffff8023d199>] sys_gettimeofday+0x0/0x62
[<ffffffff8047636c>] text_poke+0x119/0x124
[<ffffffff80476b42>] arch_arm_kprobe+0x1c/0x21
[<ffffffff80477cfd>] __register_kprobe+0x28a/0x2ed
[<ffffffff8815a039>] :gettimeofday:kprobe_init+0x39/0x65
[<ffffffff8025b5cf>] sys_init_module+0x1626/0x1788
[<ffffffff802aaf12>] dput+0x3f/0xfa
[<ffffffff8026bf91>] audit_syscall_entry+0x141/0x174
[<ffffffff8020bee5>] tracesys+0xdc/0xe1
======================================================
This indicates that vunmap() is not receving the page-aligned address in
text_poke(). So the below attached patch will address this issue. Please let
me know your comments.
Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Index: linux-2.6.23-rc1/arch/i386/kernel/alternative.c
===================================================================
--- linux-2.6.23-rc1.orig/arch/i386/kernel/alternative.c 2007-07-23
02:11:00.000000000 +0530
+++ linux-2.6.23-rc1/arch/i386/kernel/alternative.c 2007-07-25
11:45:53.000000000 +0530
@@ -447,5 +447,5 @@ void __kprobes text_poke(void *oaddr, un
if (cpu_has_clflush)
asm("clflush (%0) " :: "r" (oaddr) : "memory");
if (addr != oaddr)
- vunmap(addr);
+ vunmap(addr-(((unsigned long)oaddr) % PAGE_SIZE));
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes)
2007-07-25 13:01 [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes) Srinivasa Ds
@ 2007-07-25 15:22 ` S. P. Prasanna
2007-07-25 17:33 ` Srinivasa Ds
0 siblings, 1 reply; 3+ messages in thread
From: S. P. Prasanna @ 2007-07-25 15:22 UTC (permalink / raw)
To: Srinivasa Ds
Cc: linux-kernel, Andrew Morton, ananth, anil.s.keshavamurthy,
jkenisto, systemtap, suzuki
On Wed, Jul 25, 2007 at 12:21:49PM +0530, Srinivasa Ds wrote:
>
> When I was testing kprobes on x86_64 and I come across the below error message
> on latest 2.6.23-rc1 kernel.
> ==========================================
> Trying to vfree() bad address (ffffc20002233199)
> WARNING: at mm/vmalloc.c:330 __vunmap()
>
> Call Trace:
> [<ffffffff8023d199>] sys_gettimeofday+0x0/0x62
> [<ffffffff8047636c>] text_poke+0x119/0x124
> [<ffffffff80476b42>] arch_arm_kprobe+0x1c/0x21
> [<ffffffff80477cfd>] __register_kprobe+0x28a/0x2ed
> [<ffffffff8815a039>] :gettimeofday:kprobe_init+0x39/0x65
> [<ffffffff8025b5cf>] sys_init_module+0x1626/0x1788
> [<ffffffff802aaf12>] dput+0x3f/0xfa
> [<ffffffff8026bf91>] audit_syscall_entry+0x141/0x174
> [<ffffffff8020bee5>] tracesys+0xdc/0xe1
>
> ======================================================
>
> This indicates that vunmap() is not receving the page-aligned address in
> text_poke(). So the below attached patch will address this issue. Please let
> me know your comments.
>
> Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
> Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
>
>
> Index: linux-2.6.23-rc1/arch/i386/kernel/alternative.c
> ===================================================================
> --- linux-2.6.23-rc1.orig/arch/i386/kernel/alternative.c 2007-07-23
> 02:11:00.000000000 +0530
> +++ linux-2.6.23-rc1/arch/i386/kernel/alternative.c 2007-07-25
> 11:45:53.000000000 +0530
> @@ -447,5 +447,5 @@ void __kprobes text_poke(void *oaddr, un
> if (cpu_has_clflush)
> asm("clflush (%0) " :: "r" (oaddr) : "memory");
> if (addr != oaddr)
> - vunmap(addr);
> + vunmap(addr-(((unsigned long)oaddr) % PAGE_SIZE));
It is appropriate to use PAGE_MASK rather than doing all this,
as shown below.
vunmap((u8 *)((unsigned long)addr & PAGE_MASK));
Thanks
Prasanna
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: prasanna@in.ibm.com
Ph: 91-80-41776329
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes)
2007-07-25 15:22 ` S. P. Prasanna
@ 2007-07-25 17:33 ` Srinivasa Ds
0 siblings, 0 replies; 3+ messages in thread
From: Srinivasa Ds @ 2007-07-25 17:33 UTC (permalink / raw)
To: prasanna, linux-kernel, Andrew Morton, anil.s.keshavamurthy,
jkenisto, systemtap, ak
Cc: suzuki
Resending patch according to Prasanna's suggestion, CC'ing Andi Kleen.
Hit this issue when testing kprobes on x86_64 systems. We need to align
vunmap() address to a page boundary in text_poke(). Patch below
==============================
Trying to vfree() bad address (ffffc20002233199)
WARNING: at mm/vmalloc.c:330 __vunmap()
Call Trace:
[<ffffffff8023d199>] sys_gettimeofday+0x0/0x62
[<ffffffff8047636c>] text_poke+0x119/0x124
[<ffffffff80476b42>] arch_arm_kprobe+0x1c/0x21
[<ffffffff80477cfd>] __register_kprobe+0x28a/0x2ed
[<ffffffff8815a039>] :gettimeofday:kprobe_init+0x39/0x65
[<ffffffff8025b5cf>] sys_init_module+0x1626/0x1788
[<ffffffff802aaf12>] dput+0x3f/0xfa
[<ffffffff8026bf91>] audit_syscall_entry+0x141/0x174
[<ffffffff8020bee5>] tracesys+0xdc/0xe1
========================================
Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Index: linux-2.6.23-rc1/arch/i386/kernel/alternative.c
===================================================================
--- linux-2.6.23-rc1.orig/arch/i386/kernel/alternative.c 2007-07-23
02:11:00.000000000 +0530
+++ linux-2.6.23-rc1/arch/i386/kernel/alternative.c 2007-07-25
20:27:13.000000000 +0530
@@ -447,5 +447,5 @@ void __kprobes text_poke(void *oaddr, un
if (cpu_has_clflush)
asm("clflush (%0) " :: "r" (oaddr) : "memory");
if (addr != oaddr)
- vunmap(addr);
+ vunmap((u8 *)((unsigned long)addr & PAGE_MASK));
}
^ permalink raw reply [flat|nested] 3+ messages in thread
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2007-07-25 13:01 [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes) Srinivasa Ds
2007-07-25 15:22 ` S. P. Prasanna
2007-07-25 17:33 ` Srinivasa Ds
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