Re: [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes)
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 (c20002233199)
> WARNING: at mm/vmalloc.c:330 __vunmap()
>
> Call Trace:
> [] sys_gettimeofday+0x0/0x62
> [] text_poke+0x119/0x124
> [] arch_arm_kprobe+0x1c/0x21
> [] __register_kprobe+0x28a/0x2ed
> [] :gettimeofday:kprobe_init+0x39/0x65
> [] sys_init_module+0x1626/0x1788
> [] dput+0x3f/0xfa
> [] audit_syscall_entry+0x141/0x174
> [] 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 <[EMAIL PROTECTED]>
> Signed-off-by: Suzuki K P <[EMAIL PROTECTED]>
>
>
> 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
> 02:11:00.0 +0530
> +++ linux-2.6.23-rc1/arch/i386/kernel/alternative.c 2007-07-25
> 11:45:53.0 +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: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC] [PATCH] To vunmap correct address in text_poke()(kprobes)
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 (c20002233199) WARNING: at mm/vmalloc.c:330 __vunmap() Call Trace: [8023d199] sys_gettimeofday+0x0/0x62 [8047636c] text_poke+0x119/0x124 [80476b42] arch_arm_kprobe+0x1c/0x21 [80477cfd] __register_kprobe+0x28a/0x2ed [8815a039] :gettimeofday:kprobe_init+0x39/0x65 [8025b5cf] sys_init_module+0x1626/0x1788 [802aaf12] dput+0x3f/0xfa [8026bf91] audit_syscall_entry+0x141/0x174 [8020bee5] 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 [EMAIL PROTECTED] Signed-off-by: Suzuki K P [EMAIL PROTECTED] 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 02:11:00.0 +0530 +++ linux-2.6.23-rc1/arch/i386/kernel/alternative.c 2007-07-25 11:45:53.0 +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: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 3/3] Text Edit Lock - kprobes i386
On Tue, Jul 03, 2007 at 12:38:22PM -0400, Mathieu Desnoyers wrote:
> Kprobes can use the text edit lock to insure mutual exclusion when edition the
> code and make sure the pages are writable.
Linus suggested for splitting ro-data and ro-text; And allow ro-text
only if kprobes is not configured.
Please see the discussion thread, URL given below
http://lkml.org/lkml/2007/6/20/436
This patch below allows to configure and mark the kernel text and
kernel data as read-only separately. Also kernel text
is configured read-only if kprobes is not configured.
Thanks
Prasanna
This patch allows to configure and mark the kernel text and
kernel data as read-only separately.
Signed-off-by: Prasanna S P. <[EMAIL PROTECTED]>
arch/i386/Kconfig.debug |8
arch/i386/mm/init.c | 22 --
2 files changed, 24 insertions(+), 6 deletions(-)
diff -puN arch/i386/Kconfig.debug~mark-kernel-text-data-ro-seperately-i386
arch/i386/Kconfig.debug
---
linux-2.6.22-rc6/arch/i386/Kconfig.debug~mark-kernel-text-data-ro-seperately-i386
2007-07-04 13:45:24.0 +0530
+++ linux-2.6.22-rc6-prasanna/arch/i386/Kconfig.debug 2007-07-04
13:52:31.0 +0530
@@ -56,6 +56,14 @@ config DEBUG_RODATA
portion of the kernel code won't be covered by a 2MB TLB anymore.
If in doubt, say "N".
+config DEBUG_ROTEXT
+ bool "Write protect kernel text"
+ depends on DEBUG_RODATA && !KPROBES
+ help
+ Mark the kernel text as write-protected in the pagetables.
+ Only allow this if kprobes is not configured.
+ If in doubt, say "N".
+
config 4KSTACKS
bool "Use 4Kb for kernel stacks instead of 8Kb"
depends on DEBUG_KERNEL
diff -puN arch/i386/mm/init.c~mark-kernel-text-data-ro-seperately-i386
arch/i386/mm/init.c
---
linux-2.6.22-rc6/arch/i386/mm/init.c~mark-kernel-text-data-ro-seperately-i386
2007-07-04 13:45:24.0 +0530
+++ linux-2.6.22-rc6-prasanna/arch/i386/mm/init.c 2007-07-04
13:51:39.0 +0530
@@ -792,14 +792,11 @@ static int noinline do_test_wp_bit(void)
return flag;
}
-#ifdef CONFIG_DEBUG_RODATA
-
-void mark_rodata_ro(void)
+static inline void mark_rwtext_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
-#ifndef CONFIG_KPROBES
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
if (num_possible_cpus() <= 1)
@@ -809,9 +806,22 @@ void mark_rodata_ro(void)
size >> PAGE_SHIFT, PAGE_KERNEL_RX);
printk("Write protecting the kernel text: %luk\n", size >> 10);
}
+
+ /*
+* global_flush_tlb() will be called after marking the data as readonly.
+*/
+}
+
+#ifdef CONFIG_DEBUG_RODATA
+
+void mark_rodata_ro(void)
+{
+ unsigned long start = PFN_ALIGN(_etext);
+ unsigned long size = (unsigned long)__end_rodata - start;
+
+#ifdef CONFIG_DEBUG_ROTEXT
+ mark_rwtext_ro();
#endif
- start += size;
- size = (unsigned long)__end_rodata - start;
change_page_attr(virt_to_page(start),
size >> PAGE_SHIFT, PAGE_KERNEL_RO);
printk("Write protecting the kernel read-only data: %luk\n",
_
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 3/3] Text Edit Lock - kprobes i386
On Tue, Jul 03, 2007 at 12:38:22PM -0400, Mathieu Desnoyers wrote:
Kprobes can use the text edit lock to insure mutual exclusion when edition the
code and make sure the pages are writable.
Linus suggested for splitting ro-data and ro-text; And allow ro-text
only if kprobes is not configured.
Please see the discussion thread, URL given below
http://lkml.org/lkml/2007/6/20/436
This patch below allows to configure and mark the kernel text and
kernel data as read-only separately. Also kernel text
is configured read-only if kprobes is not configured.
Thanks
Prasanna
This patch allows to configure and mark the kernel text and
kernel data as read-only separately.
Signed-off-by: Prasanna S P. [EMAIL PROTECTED]
arch/i386/Kconfig.debug |8
arch/i386/mm/init.c | 22 --
2 files changed, 24 insertions(+), 6 deletions(-)
diff -puN arch/i386/Kconfig.debug~mark-kernel-text-data-ro-seperately-i386
arch/i386/Kconfig.debug
---
linux-2.6.22-rc6/arch/i386/Kconfig.debug~mark-kernel-text-data-ro-seperately-i386
2007-07-04 13:45:24.0 +0530
+++ linux-2.6.22-rc6-prasanna/arch/i386/Kconfig.debug 2007-07-04
13:52:31.0 +0530
@@ -56,6 +56,14 @@ config DEBUG_RODATA
portion of the kernel code won't be covered by a 2MB TLB anymore.
If in doubt, say N.
+config DEBUG_ROTEXT
+ bool Write protect kernel text
+ depends on DEBUG_RODATA !KPROBES
+ help
+ Mark the kernel text as write-protected in the pagetables.
+ Only allow this if kprobes is not configured.
+ If in doubt, say N.
+
config 4KSTACKS
bool Use 4Kb for kernel stacks instead of 8Kb
depends on DEBUG_KERNEL
diff -puN arch/i386/mm/init.c~mark-kernel-text-data-ro-seperately-i386
arch/i386/mm/init.c
---
linux-2.6.22-rc6/arch/i386/mm/init.c~mark-kernel-text-data-ro-seperately-i386
2007-07-04 13:45:24.0 +0530
+++ linux-2.6.22-rc6-prasanna/arch/i386/mm/init.c 2007-07-04
13:51:39.0 +0530
@@ -792,14 +792,11 @@ static int noinline do_test_wp_bit(void)
return flag;
}
-#ifdef CONFIG_DEBUG_RODATA
-
-void mark_rodata_ro(void)
+static inline void mark_rwtext_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
-#ifndef CONFIG_KPROBES
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
if (num_possible_cpus() = 1)
@@ -809,9 +806,22 @@ void mark_rodata_ro(void)
size PAGE_SHIFT, PAGE_KERNEL_RX);
printk(Write protecting the kernel text: %luk\n, size 10);
}
+
+ /*
+* global_flush_tlb() will be called after marking the data as readonly.
+*/
+}
+
+#ifdef CONFIG_DEBUG_RODATA
+
+void mark_rodata_ro(void)
+{
+ unsigned long start = PFN_ALIGN(_etext);
+ unsigned long size = (unsigned long)__end_rodata - start;
+
+#ifdef CONFIG_DEBUG_ROTEXT
+ mark_rwtext_ro();
#endif
- start += size;
- size = (unsigned long)__end_rodata - start;
change_page_attr(virt_to_page(start),
size PAGE_SHIFT, PAGE_KERNEL_RO);
printk(Write protecting the kernel read-only data: %luk\n,
_
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [1/2] 2.6.22-rc5: known regressions with patches
On Wed, Jun 20, 2007 at 10:23:21PM -0700, Arjan van de Ven wrote:
> On Wed, 2007-06-20 at 16:50 -0700, Linus Torvalds wrote:
> >
> > On Wed, 20 Jun 2007, Arjan van de Ven wrote:
> > >
> > > the real fix would be something like this instead:
> >
> > If people can test this, and confirm it works, please send a patch that
> > not only does this ad undoes the Kconfig language. It looks like the
> > right thing to do, but I won't touch it without somebody who actually
> > tested these combinarions sending in a patch.
>
> Hi,
>
> I have tested this on x86_64, and without the config language, the
> original oopses, while with the patch below it works fine (as expected).
> I've not been able to test the i386 one (no 32 bit testboxes since 2
> years) but the change is even simpler there, just an ifdef around the
> entire kernel text marking.
I tested this patch on i386 box, it seems to work fine.
Thanks
Prasanna
>
>
>
> Do not mark the kernel text read only if KPROBES is in the kernel;
> kprobes needs to hot-patch the kernel text to insert it's
> instrumentation. In this case, only mark the .rodata segment as read
> only.
>
> Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]>
>
> --- linux-2.6.22-rc5/arch/i386/Kconfig.debug.org 2007-06-20
> 22:20:30.0 -0700
> +++ linux-2.6.22-rc5/arch/i386/Kconfig.debug 2007-06-20 22:20:55.0
> -0700
> @@ -49,7 +49,6 @@ config DEBUG_PAGEALLOC
> config DEBUG_RODATA
> bool "Write protect kernel read-only data structures"
> depends on DEBUG_KERNEL
> - depends on !KPROBES # temporary for 2.6.22
> help
> Mark the kernel read-only data as write-protected in the pagetables,
> in order to catch accidental (and incorrect) writes to such const
> --- linux-2.6.22-rc5/arch/x86_64/Kconfig.debug.org2007-06-20
> 22:20:28.0 -0700
> +++ linux-2.6.22-rc5/arch/x86_64/Kconfig.debug2007-06-20
> 22:20:44.0 -0700
> @@ -9,7 +9,6 @@ source "lib/Kconfig.debug"
> config DEBUG_RODATA
> bool "Write protect kernel read-only data structures"
> depends on DEBUG_KERNEL
> - depends on !KPROBES # temporary for 2.6.22
> help
>Mark the kernel read-only data as write-protected in the pagetables,
>in order to catch accidental (and incorrect) writes to such const data.
> --- linux-2.6.22-rc5/arch/i386/mm/init.c.org 2007-06-20 22:18:40.0
> -0700
> +++ linux-2.6.22-rc5/arch/i386/mm/init.c 2007-06-20 22:19:45.0
> -0700
> @@ -799,6 +799,7 @@ void mark_rodata_ro(void)
> unsigned long start = PFN_ALIGN(_text);
> unsigned long size = PFN_ALIGN(_etext) - start;
>
> +#ifndef CONFIG_KPROBES
> #ifdef CONFIG_HOTPLUG_CPU
> /* It must still be possible to apply SMP alternatives. */
> if (num_possible_cpus() <= 1)
> @@ -808,7 +809,7 @@ void mark_rodata_ro(void)
>size >> PAGE_SHIFT, PAGE_KERNEL_RX);
> printk("Write protecting the kernel text: %luk\n", size >> 10);
> }
> -
> +#endif
> start += size;
> size = (unsigned long)__end_rodata - start;
> change_page_attr(virt_to_page(start),
> --- linux-2.6.22-rc5/arch/x86_64/mm/init.c.org2007-06-20
> 21:44:15.0 -0700
> +++ linux-2.6.22-rc5/arch/x86_64/mm/init.c2007-06-20 22:17:45.0
> -0700
> @@ -605,6 +605,11 @@ void mark_rodata_ro(void)
> if (num_possible_cpus() > 1)
> start = (unsigned long)_etext;
> #endif
> +
> +#ifdef CONFIG_KPROBES
> + start = (unsigned long)__start_rodata;
> +#endif
> +
> end = (unsigned long)__end_rodata;
> start = (start + PAGE_SIZE - 1) & PAGE_MASK;
> end &= PAGE_MASK;
>
> --
> if you want to mail me at work (you don't), use arjan (at) linux.intel.com
> Test the interaction between Linux and your BIOS via
> http://www.linuxfirmwarekit.org
--
Thanks & Regards
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [1/2] 2.6.22-rc5: known regressions with patches
On Wed, Jun 20, 2007 at 10:23:21PM -0700, Arjan van de Ven wrote: On Wed, 2007-06-20 at 16:50 -0700, Linus Torvalds wrote: On Wed, 20 Jun 2007, Arjan van de Ven wrote: the real fix would be something like this instead: If people can test this, and confirm it works, please send a patch that not only does this ad undoes the Kconfig language. It looks like the right thing to do, but I won't touch it without somebody who actually tested these combinarions sending in a patch. Hi, I have tested this on x86_64, and without the config language, the original oopses, while with the patch below it works fine (as expected). I've not been able to test the i386 one (no 32 bit testboxes since 2 years) but the change is even simpler there, just an ifdef around the entire kernel text marking. I tested this patch on i386 box, it seems to work fine. Thanks Prasanna Do not mark the kernel text read only if KPROBES is in the kernel; kprobes needs to hot-patch the kernel text to insert it's instrumentation. In this case, only mark the .rodata segment as read only. Signed-off-by: Arjan van de Ven [EMAIL PROTECTED] --- linux-2.6.22-rc5/arch/i386/Kconfig.debug.org 2007-06-20 22:20:30.0 -0700 +++ linux-2.6.22-rc5/arch/i386/Kconfig.debug 2007-06-20 22:20:55.0 -0700 @@ -49,7 +49,6 @@ config DEBUG_PAGEALLOC config DEBUG_RODATA bool Write protect kernel read-only data structures depends on DEBUG_KERNEL - depends on !KPROBES # temporary for 2.6.22 help Mark the kernel read-only data as write-protected in the pagetables, in order to catch accidental (and incorrect) writes to such const --- linux-2.6.22-rc5/arch/x86_64/Kconfig.debug.org2007-06-20 22:20:28.0 -0700 +++ linux-2.6.22-rc5/arch/x86_64/Kconfig.debug2007-06-20 22:20:44.0 -0700 @@ -9,7 +9,6 @@ source lib/Kconfig.debug config DEBUG_RODATA bool Write protect kernel read-only data structures depends on DEBUG_KERNEL - depends on !KPROBES # temporary for 2.6.22 help Mark the kernel read-only data as write-protected in the pagetables, in order to catch accidental (and incorrect) writes to such const data. --- linux-2.6.22-rc5/arch/i386/mm/init.c.org 2007-06-20 22:18:40.0 -0700 +++ linux-2.6.22-rc5/arch/i386/mm/init.c 2007-06-20 22:19:45.0 -0700 @@ -799,6 +799,7 @@ void mark_rodata_ro(void) unsigned long start = PFN_ALIGN(_text); unsigned long size = PFN_ALIGN(_etext) - start; +#ifndef CONFIG_KPROBES #ifdef CONFIG_HOTPLUG_CPU /* It must still be possible to apply SMP alternatives. */ if (num_possible_cpus() = 1) @@ -808,7 +809,7 @@ void mark_rodata_ro(void) size PAGE_SHIFT, PAGE_KERNEL_RX); printk(Write protecting the kernel text: %luk\n, size 10); } - +#endif start += size; size = (unsigned long)__end_rodata - start; change_page_attr(virt_to_page(start), --- linux-2.6.22-rc5/arch/x86_64/mm/init.c.org2007-06-20 21:44:15.0 -0700 +++ linux-2.6.22-rc5/arch/x86_64/mm/init.c2007-06-20 22:17:45.0 -0700 @@ -605,6 +605,11 @@ void mark_rodata_ro(void) if (num_possible_cpus() 1) start = (unsigned long)_etext; #endif + +#ifdef CONFIG_KPROBES + start = (unsigned long)__start_rodata; +#endif + end = (unsigned long)__end_rodata; start = (start + PAGE_SIZE - 1) PAGE_MASK; end = PAGE_MASK; -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org -- Thanks Regards Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 2/2] kprobes x86_64 quick fix mark-ro-data
On Tue, Jun 19, 2007 at 06:44:30AM -0700, Arjan van de Ven wrote:
> On Tue, 2007-06-19 at 09:30 -0400, Mathieu Desnoyers wrote:
> > * Arjan van de Ven ([EMAIL PROTECTED]) wrote:
> > > On Tue, 2007-06-19 at 15:38 +0530, S. P. Prasanna wrote:
> > > > This patch is a quick fix for x86_64 to enable kprobes only if
> > > > DEBUG_RODATA is
> > > > not configured. Since DEBUG_RODATA markes the kernel text pages as
> > > > read-only.
> > >
> > >
> > > it does??
> > >
> > > I don't seem to be able to find this in the source code.
> > >
>
> > See arch/x86_64/mm/init.c:mark_rodata_ro().
>
> eh woops
>
>
> PATCH] x86: tighten kernel image page access rights
> author
> Jan Beulich <[EMAIL PROTECTED]>
>
> Wed, 2 May 2007 17:27:10 +
> (19:27 +0200)
> committer
> Andi Kleen <[EMAIL PROTECTED]>
>
> Wed, 2 May 2007 17:27:10 +
> (19:27 +0200)
> commit
> 6fb14755a676282a4e6caa05a08c92db8e45cfff
>
>
> changed it to include text (even though Andi vetoed that before when I
> asked for it on grounds of breaking kprobes)... sounds this really wants
> to be a 2nd config option to seperatedly do code and data.
Something like having a seperate config option and a routine
to mark kernel text as read execute only.
And call mark_rwtext_ro() if CONFIG_DEBUG_ROTEXT is enabled
below in mark_rodata_ro().
/* this code is for i386 architecture*/
static inline void mark_rwtext_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
if (num_possible_cpus() <= 1)
#endif
{
change_page_attr(virt_to_page(start),
size >> PAGE_SHIFT, PAGE_KERNEL_RX);
printk("Write protecting the kernel text: %luk\n", size >> 10);
}
/*
* global_flush_tlb() will be called after marking the data as readonly.
*/
}
#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void)
{
#ifdef CONFIG_DEBUG_ROTEXT
mark_rwtext_ro();
#endif
}
Thanks
Prasanna
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 2/2] kprobes x86_64 quick fix mark-ro-data
This patch is a quick fix for x86_64 to enable kprobes only if DEBUG_RODATA is not configured. Since DEBUG_RODATA markes the kernel text pages as read-only. Signed-off-by: Prasanna S P. <[EMAIL PROTECTED]> arch/x86_64/Kconfig |6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff -puN arch/x86_64/Kconfig~kprobes-quick-fix-mark-ro-data-x86_64 arch/x86_64/Kconfig --- linux-2.6.22-rc5/arch/x86_64/Kconfig~kprobes-quick-fix-mark-ro-data-x86_64 2007-06-19 14:55:56.0 +0530 +++ linux-2.6.22-rc5-prasanna/arch/x86_64/Kconfig 2007-06-19 14:55:56.0 +0530 @@ -764,6 +764,8 @@ source "drivers/firmware/Kconfig" source fs/Kconfig +source "arch/x86_64/Kconfig.debug" + menu "Instrumentation Support" depends on EXPERIMENTAL @@ -771,7 +773,7 @@ source "arch/x86_64/oprofile/Kconfig" config KPROBES bool "Kprobes (EXPERIMENTAL)" - depends on KALLSYMS && EXPERIMENTAL && MODULES + depends on KALLSYMS && EXPERIMENTAL && MODULES && !DEBUG_RODATA help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes @@ -780,8 +782,6 @@ config KPROBES If in doubt, say "N". endmenu -source "arch/x86_64/Kconfig.debug" - source "security/Kconfig" source "crypto/Kconfig" _ -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 1/2] kprobes i386 quick fix mark-ro-data
On Mon, Jun 18, 2007 at 09:32:56PM +0200, Andi Kleen wrote: > On Monday 18 June 2007 20:56:32 Andrew Morton wrote: > > On Mon, 18 Jun 2007 14:44:57 -0400 > > Chuck Ebbert <[EMAIL PROTECTED]> wrote: > > > > > > I fancy it's done by the kprobe_page_fault handler, but I do not see > > > > clearly how writing the breakpoint from arch_arm_kprobe() in > > > > non-writeable memory is done. > > > > > > Looks like it's not merged yet: > > > > > > http://lkml.org/lkml/2007/6/7/2 > > > > > > This needs to go in before 2.6.22-final > > > > Andi, I'll include the below two patches in the next batch, OK? > > It won't work reliably unless some of the c_p_a() fixes get in first. > > > > > > > > > +extern int kernel_text_is_ro; > > No externs in .c files Yes. > > > I also don't like kernel_text_is_read_only() much, it would > be better to just lookup_address() it and check the write flag. Yes, I will look into this approach. > > But for 2.6.22 as a quick fix it might be better to just > make KPROBES dependent on !DEBUG_RODATA. That would be a one liner. > Please find the quick fix as per your suggestion below. Thanks Prasanna This patch is a quick fix to enable kprobes only if DEBUG_RODATA is not configured. Since DEBUG_RODATA markes the kernel text pages as read-only. Signed-off-by: Prasanna S P. <[EMAIL PROTECTED]> arch/i386/Kconfig |6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff -puN arch/i386/Kconfig~kprobes-quick-fix-mark-ro-data-i386 arch/i386/Kconfig --- linux-2.6.22-rc5/arch/i386/Kconfig~kprobes-quick-fix-mark-ro-data-i386 2007-06-19 14:55:31.0 +0530 +++ linux-2.6.22-rc5-prasanna/arch/i386/Kconfig 2007-06-19 14:55:31.0 +0530 @@ -1212,6 +1212,8 @@ source "drivers/Kconfig" source "fs/Kconfig" +source "arch/i386/Kconfig.debug" + menu "Instrumentation Support" depends on EXPERIMENTAL @@ -1219,7 +1221,7 @@ source "arch/i386/oprofile/Kconfig" config KPROBES bool "Kprobes (EXPERIMENTAL)" - depends on KALLSYMS && EXPERIMENTAL && MODULES + depends on KALLSYMS && EXPERIMENTAL && MODULES && !DEBUG_RODATA help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes @@ -1228,8 +1230,6 @@ config KPROBES If in doubt, say "N". endmenu -source "arch/i386/Kconfig.debug" - source "security/Kconfig" source "crypto/Kconfig" _ -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 1/2] kprobes i386 quick fix mark-ro-data
On Mon, Jun 18, 2007 at 09:32:56PM +0200, Andi Kleen wrote: On Monday 18 June 2007 20:56:32 Andrew Morton wrote: On Mon, 18 Jun 2007 14:44:57 -0400 Chuck Ebbert [EMAIL PROTECTED] wrote: I fancy it's done by the kprobe_page_fault handler, but I do not see clearly how writing the breakpoint from arch_arm_kprobe() in non-writeable memory is done. Looks like it's not merged yet: http://lkml.org/lkml/2007/6/7/2 This needs to go in before 2.6.22-final Andi, I'll include the below two patches in the next batch, OK? It won't work reliably unless some of the c_p_a() fixes get in first. +extern int kernel_text_is_ro; No externs in .c files Yes. I also don't like kernel_text_is_read_only() much, it would be better to just lookup_address() it and check the write flag. Yes, I will look into this approach. But for 2.6.22 as a quick fix it might be better to just make KPROBES dependent on !DEBUG_RODATA. That would be a one liner. Please find the quick fix as per your suggestion below. Thanks Prasanna This patch is a quick fix to enable kprobes only if DEBUG_RODATA is not configured. Since DEBUG_RODATA markes the kernel text pages as read-only. Signed-off-by: Prasanna S P. [EMAIL PROTECTED] arch/i386/Kconfig |6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff -puN arch/i386/Kconfig~kprobes-quick-fix-mark-ro-data-i386 arch/i386/Kconfig --- linux-2.6.22-rc5/arch/i386/Kconfig~kprobes-quick-fix-mark-ro-data-i386 2007-06-19 14:55:31.0 +0530 +++ linux-2.6.22-rc5-prasanna/arch/i386/Kconfig 2007-06-19 14:55:31.0 +0530 @@ -1212,6 +1212,8 @@ source drivers/Kconfig source fs/Kconfig +source arch/i386/Kconfig.debug + menu Instrumentation Support depends on EXPERIMENTAL @@ -1219,7 +1221,7 @@ source arch/i386/oprofile/Kconfig config KPROBES bool Kprobes (EXPERIMENTAL) - depends on KALLSYMS EXPERIMENTAL MODULES + depends on KALLSYMS EXPERIMENTAL MODULES !DEBUG_RODATA help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes @@ -1228,8 +1230,6 @@ config KPROBES If in doubt, say N. endmenu -source arch/i386/Kconfig.debug - source security/Kconfig source crypto/Kconfig _ -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 2/2] kprobes x86_64 quick fix mark-ro-data
This patch is a quick fix for x86_64 to enable kprobes only if DEBUG_RODATA is not configured. Since DEBUG_RODATA markes the kernel text pages as read-only. Signed-off-by: Prasanna S P. [EMAIL PROTECTED] arch/x86_64/Kconfig |6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff -puN arch/x86_64/Kconfig~kprobes-quick-fix-mark-ro-data-x86_64 arch/x86_64/Kconfig --- linux-2.6.22-rc5/arch/x86_64/Kconfig~kprobes-quick-fix-mark-ro-data-x86_64 2007-06-19 14:55:56.0 +0530 +++ linux-2.6.22-rc5-prasanna/arch/x86_64/Kconfig 2007-06-19 14:55:56.0 +0530 @@ -764,6 +764,8 @@ source drivers/firmware/Kconfig source fs/Kconfig +source arch/x86_64/Kconfig.debug + menu Instrumentation Support depends on EXPERIMENTAL @@ -771,7 +773,7 @@ source arch/x86_64/oprofile/Kconfig config KPROBES bool Kprobes (EXPERIMENTAL) - depends on KALLSYMS EXPERIMENTAL MODULES + depends on KALLSYMS EXPERIMENTAL MODULES !DEBUG_RODATA help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes @@ -780,8 +782,6 @@ config KPROBES If in doubt, say N. endmenu -source arch/x86_64/Kconfig.debug - source security/Kconfig source crypto/Kconfig _ -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 2/2] kprobes x86_64 quick fix mark-ro-data
On Tue, Jun 19, 2007 at 06:44:30AM -0700, Arjan van de Ven wrote:
On Tue, 2007-06-19 at 09:30 -0400, Mathieu Desnoyers wrote:
* Arjan van de Ven ([EMAIL PROTECTED]) wrote:
On Tue, 2007-06-19 at 15:38 +0530, S. P. Prasanna wrote:
This patch is a quick fix for x86_64 to enable kprobes only if
DEBUG_RODATA is
not configured. Since DEBUG_RODATA markes the kernel text pages as
read-only.
it does??
I don't seem to be able to find this in the source code.
See arch/x86_64/mm/init.c:mark_rodata_ro().
eh woops
PATCH] x86: tighten kernel image page access rights
author
Jan Beulich [EMAIL PROTECTED]
Wed, 2 May 2007 17:27:10 +
(19:27 +0200)
committer
Andi Kleen [EMAIL PROTECTED]
Wed, 2 May 2007 17:27:10 +
(19:27 +0200)
commit
6fb14755a676282a4e6caa05a08c92db8e45cfff
changed it to include text (even though Andi vetoed that before when I
asked for it on grounds of breaking kprobes)... sounds this really wants
to be a 2nd config option to seperatedly do code and data.
Something like having a seperate config option and a routine
to mark kernel text as read execute only.
And call mark_rwtext_ro() if CONFIG_DEBUG_ROTEXT is enabled
below in mark_rodata_ro().
/* this code is for i386 architecture*/
static inline void mark_rwtext_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
if (num_possible_cpus() = 1)
#endif
{
change_page_attr(virt_to_page(start),
size PAGE_SHIFT, PAGE_KERNEL_RX);
printk(Write protecting the kernel text: %luk\n, size 10);
}
/*
* global_flush_tlb() will be called after marking the data as readonly.
*/
}
#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void)
{
#ifdef CONFIG_DEBUG_ROTEXT
mark_rwtext_ro();
#endif
}
Thanks
Prasanna
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [2.6 patch] include/linux/kprobes.h: always offer show_registers() prototype
On Mon, Jun 18, 2007 at 01:43:04AM +0200, Adrian Bunk wrote:
> Allow gcc to perform show_registers() type checking also with
> CONFIG_KPROBES=n.
>
Adrian,
Please implement it as Andrew suggested, when this was patch was posted
eariler. Refer this discussion thread below.
http://lkml.org/lkml/2007/4/27/576
NACK
Thanks
Prasanna
> Signed-off-by: Adrian Bunk <[EMAIL PROTECTED]>
>
> ---
>
> This patch has been sent on:
> - 27 Apr 2007
> - 27 Mar 2007
>
> include/linux/kprobes.h |4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> --- linux-2.6.21-rc4-mm1/include/linux/kprobes.h.old 2007-03-26
> 15:28:27.0 +0200
> +++ linux-2.6.21-rc4-mm1/include/linux/kprobes.h 2007-03-26
> 15:32:23.0 +0200
> @@ -163,7 +163,6 @@
> extern void arch_arm_kprobe(struct kprobe *p);
> extern void arch_disarm_kprobe(struct kprobe *p);
> extern int arch_init_kprobes(void);
> -extern void show_registers(struct pt_regs *regs);
> extern kprobe_opcode_t *get_insn_slot(void);
> extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
> extern void kprobes_inc_nmissed_count(struct kprobe *p);
> @@ -241,4 +240,7 @@
> {
> }
> #endif /* CONFIG_KPROBES */
> +
> +void show_registers(struct pt_regs *regs);
> +
> #endif /* _LINUX_KPROBES_H */
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [2.6 patch] include/linux/kprobes.h: always offer show_registers() prototype
On Mon, Jun 18, 2007 at 01:43:04AM +0200, Adrian Bunk wrote:
Allow gcc to perform show_registers() type checking also with
CONFIG_KPROBES=n.
Adrian,
Please implement it as Andrew suggested, when this was patch was posted
eariler. Refer this discussion thread below.
http://lkml.org/lkml/2007/4/27/576
NACK
Thanks
Prasanna
Signed-off-by: Adrian Bunk [EMAIL PROTECTED]
---
This patch has been sent on:
- 27 Apr 2007
- 27 Mar 2007
include/linux/kprobes.h |4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- linux-2.6.21-rc4-mm1/include/linux/kprobes.h.old 2007-03-26
15:28:27.0 +0200
+++ linux-2.6.21-rc4-mm1/include/linux/kprobes.h 2007-03-26
15:32:23.0 +0200
@@ -163,7 +163,6 @@
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
-extern void show_registers(struct pt_regs *regs);
extern kprobe_opcode_t *get_insn_slot(void);
extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
@@ -241,4 +240,7 @@
{
}
#endif /* CONFIG_KPROBES */
+
+void show_registers(struct pt_regs *regs);
+
#endif /* _LINUX_KPROBES_H */
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Kprobes x86_64 fix for mark ro data
This patch fixes the problem of page protection introduced by
CONFIG_DEBUG_RODATA for x86_64 architecture. As per Andi
Kleen's suggestion, the kernel text pages are marked writeable
only for a short duration to insert or remove the breakpoints.
Signed-off-by: Prasanna S P<[EMAIL PROTECTED]>
Ack-ed-by: Jim Keniston <[EMAIL PROTECTED]>
arch/x86_64/kernel/kprobes.c | 26 ++
arch/x86_64/mm/init.c|6 +-
include/asm-x86_64/kprobes.h | 10 ++
3 files changed, 41 insertions(+), 1 deletion(-)
diff -puN arch/x86_64/kernel/kprobes.c~kprobes-mark-ro-data-fix-x86_64
arch/x86_64/kernel/kprobes.c
---
linux-2.6.22-rc2/arch/x86_64/kernel/kprobes.c~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/x86_64/kernel/kprobes.c 2007-06-07
09:20:33.0 +0530
@@ -209,16 +209,42 @@ static void __kprobes arch_copy_kprobe(s
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long)p->addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
+ global_flush_tlb();
+ page_readonly = 1;
+ }
*p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ if (page_readonly) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
+ global_flush_tlb();
+ }
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long)p->addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
+ global_flush_tlb();
+ page_readonly = 1;
+ }
+
*p->addr = p->opcode;
flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
+
+ if (page_readonly) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
+ global_flush_tlb();
+ }
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff -puN include/asm-x86_64/kprobes.h~kprobes-mark-ro-data-fix-x86_64
include/asm-x86_64/kprobes.h
---
linux-2.6.22-rc2/include/asm-x86_64/kprobes.h~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/include/asm-x86_64/kprobes.h 2007-06-07
09:20:33.0 +0530
@@ -26,6 +26,7 @@
#include
#include
#include
+#include
#define __ARCH_WANT_KPROBES_INSN_SLOT
@@ -88,4 +89,13 @@ extern int kprobe_handler(struct pt_regs
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kernel_text_is_ro;
+static inline int kernel_readonly_text(unsigned long address)
+{
+ if (kernel_text_is_ro && ((address >= (unsigned long)_stext)
+ && (address < (unsigned long) _etext)))
+ return 1;
+
+ return 0;
+}
#endif /* _ASM_KPROBES_H */
diff -puN arch/x86_64/mm/init.c~kprobes-mark-ro-data-fix-x86_64
arch/x86_64/mm/init.c
--- linux-2.6.22-rc2/arch/x86_64/mm/init.c~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/x86_64/mm/init.c 2007-06-07
09:20:33.0 +0530
@@ -48,6 +48,7 @@
#define Dprintk(x...)
#endif
+int kernel_text_is_ro;
const struct dma_mapping_ops* dma_ops;
EXPORT_SYMBOL(dma_ops);
@@ -598,10 +599,13 @@ void mark_rodata_ro(void)
{
unsigned long start = (unsigned long)_stext, end;
+ kernel_text_is_ro = 1;
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() > 1)
+ if (num_possible_cpus() > 1) {
start = (unsigned long)_etext;
+ kernel_text_is_ro = 0;
+ }
#endif
end = (unsigned long)__end_rodata;
start = (start + PAGE_SIZE - 1) & PAGE_MASK;
_
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Kprobes i386 fix for mark ro data
On Thu, Jun 07, 2007 at 11:12:32AM +1200, Ian McDonald wrote:
> On 6/7/07, Chuck Ebbert <[EMAIL PROTECTED]> wrote:
> >On 06/06/2007 04:47 PM, Ian McDonald wrote:
> >> Hi there,
> >>
> >> We've seen a report of a problem with dccp_probe as shown below. The
> >> user has also verified that it occurs in tcp_probe as well. This is on
> >> Dave Miller's tree but that currently tracks Linus' tree quite
> >> closely. I do note that it is around 2.6.22-rc2 timeframe so there is
> >> a possibility fixes may have gone in since.
> >>
> >
> >It faulted when it tried to write the breakpoint instruction into the
> >running kernel's executable code. Apparently the kernel code is now marked
> >read-only?
> >
> >
> Yes it would appear to be the case as user has CONFIG_DEBUG_RODATA
> set. Patrick - can you turn this off and retest? It's under Kernel
> Hacking, Write protect kernel read only data structures.
>
> The list of commits that I see around this are at:
> http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git=search=HEAD=commit=DEBUG_RODATA
>
> I suspect it's probably one of the latter ones giving the timing.
>
> I guess there are a couple of solutions here - either make kprobes
> conflict with CONFIG_DEBUG_RODATA so you can do one or the other, or
> look into more detail what access kprobes need.
>
> Ian
Ian,
Please find the fix as suggested by Andi Kleen
for the above stated problem.
Thanks
Prasanna
This patch fixes the problem of page protection introduced by
CONFIG_DEBUG_RODATA. CONFIG_DEBUG_RODATA marks the text pages as
read-only, hence kprobes is unable to insert breakpoints in the
kernel text. This patch overrides the page protection when adding
or removing a probe for the i386 architecture.
Signed-off-by: Prasanna S P<[EMAIL PROTECTED]>
Ack-ed-by: Jim Keniston <[EMAIL PROTECTED]>
arch/i386/kernel/kprobes.c | 26 ++
arch/i386/mm/init.c|2 ++
include/asm-i386/kprobes.h | 12
include/asm-i386/pgtable.h |2 ++
4 files changed, 42 insertions(+)
diff -puN arch/i386/kernel/kprobes.c~kprobes-mark-ro-data-fix-i386
arch/i386/kernel/kprobes.c
--- linux-2.6.22-rc2/arch/i386/kernel/kprobes.c~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/i386/kernel/kprobes.c2007-06-07
09:19:26.0 +0530
@@ -169,16 +169,42 @@ int __kprobes arch_prepare_kprobe(struct
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long) p->addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ page_readonly = 1;
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
+ global_flush_tlb();
+ }
+
*p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
+
+ if (page_readonly) {
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
+ global_flush_tlb();
+ }
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long) p->addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ page_readonly = 1;
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
+ global_flush_tlb();
+ }
*p->addr = p->opcode;
flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ if (page_readonly) {
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
+ global_flush_tlb();
+ }
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff -puN include/asm-i386/kprobes.h~kprobes-mark-ro-data-fix-i386
include/asm-i386/kprobes.h
--- linux-2.6.22-rc2/include/asm-i386/kprobes.h~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++ linux-2.6.22-rc2-prasanna/include/asm-i386/kprobes.h2007-06-07
09:19:26.0 +0530
@@ -26,6 +26,8 @@
*/
#include
#include
+#include
+#include
#define __ARCH_WANT_KPROBES_INSN_SLOT
@@ -90,4 +92,14 @@ static inline void restore_interrupts(st
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kernel_text_is_ro;
+static inline int kernel_readonly_text(unsigned long address)
+{
+
+ if (kernel_text_is_ro && ((address >= PFN_ALIGN(_text))
+ && (address < PFN_ALIGN(_etext
+ return 1;
+
+ return 0;
+}
#endif /* _ASM_KPROBES_H */
diff -puN include/asm-i386/pgtable.h~kprobes-mark-ro-data-fix-i386
include/asm-i386/pgtable.h
--- linux-2.6.22-rc2/include/asm-i386/pgtable.h~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++
Re: [PATCH] Kprobes i386 fix for mark ro data
On Thu, Jun 07, 2007 at 11:12:32AM +1200, Ian McDonald wrote:
On 6/7/07, Chuck Ebbert [EMAIL PROTECTED] wrote:
On 06/06/2007 04:47 PM, Ian McDonald wrote:
Hi there,
We've seen a report of a problem with dccp_probe as shown below. The
user has also verified that it occurs in tcp_probe as well. This is on
Dave Miller's tree but that currently tracks Linus' tree quite
closely. I do note that it is around 2.6.22-rc2 timeframe so there is
a possibility fixes may have gone in since.
It faulted when it tried to write the breakpoint instruction into the
running kernel's executable code. Apparently the kernel code is now marked
read-only?
Yes it would appear to be the case as user has CONFIG_DEBUG_RODATA
set. Patrick - can you turn this off and retest? It's under Kernel
Hacking, Write protect kernel read only data structures.
The list of commits that I see around this are at:
http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.gita=searchh=HEADst=commits=DEBUG_RODATA
I suspect it's probably one of the latter ones giving the timing.
I guess there are a couple of solutions here - either make kprobes
conflict with CONFIG_DEBUG_RODATA so you can do one or the other, or
look into more detail what access kprobes need.
Ian
Ian,
Please find the fix as suggested by Andi Kleen
for the above stated problem.
Thanks
Prasanna
This patch fixes the problem of page protection introduced by
CONFIG_DEBUG_RODATA. CONFIG_DEBUG_RODATA marks the text pages as
read-only, hence kprobes is unable to insert breakpoints in the
kernel text. This patch overrides the page protection when adding
or removing a probe for the i386 architecture.
Signed-off-by: Prasanna S P[EMAIL PROTECTED]
Ack-ed-by: Jim Keniston [EMAIL PROTECTED]
arch/i386/kernel/kprobes.c | 26 ++
arch/i386/mm/init.c|2 ++
include/asm-i386/kprobes.h | 12
include/asm-i386/pgtable.h |2 ++
4 files changed, 42 insertions(+)
diff -puN arch/i386/kernel/kprobes.c~kprobes-mark-ro-data-fix-i386
arch/i386/kernel/kprobes.c
--- linux-2.6.22-rc2/arch/i386/kernel/kprobes.c~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/i386/kernel/kprobes.c2007-06-07
09:19:26.0 +0530
@@ -169,16 +169,42 @@ int __kprobes arch_prepare_kprobe(struct
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long) p-addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ page_readonly = 1;
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
+ global_flush_tlb();
+ }
+
*p-addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p-addr,
(unsigned long) p-addr + sizeof(kprobe_opcode_t));
+
+ if (page_readonly) {
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
+ global_flush_tlb();
+ }
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long) p-addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ page_readonly = 1;
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
+ global_flush_tlb();
+ }
*p-addr = p-opcode;
flush_icache_range((unsigned long) p-addr,
(unsigned long) p-addr + sizeof(kprobe_opcode_t));
+ if (page_readonly) {
+ change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
+ global_flush_tlb();
+ }
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff -puN include/asm-i386/kprobes.h~kprobes-mark-ro-data-fix-i386
include/asm-i386/kprobes.h
--- linux-2.6.22-rc2/include/asm-i386/kprobes.h~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++ linux-2.6.22-rc2-prasanna/include/asm-i386/kprobes.h2007-06-07
09:19:26.0 +0530
@@ -26,6 +26,8 @@
*/
#include linux/types.h
#include linux/ptrace.h
+#include linux/pfn.h
+#include asm-generic/sections.h
#define __ARCH_WANT_KPROBES_INSN_SLOT
@@ -90,4 +92,14 @@ static inline void restore_interrupts(st
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kernel_text_is_ro;
+static inline int kernel_readonly_text(unsigned long address)
+{
+
+ if (kernel_text_is_ro ((address = PFN_ALIGN(_text))
+(address PFN_ALIGN(_etext
+ return 1;
+
+ return 0;
+}
#endif /* _ASM_KPROBES_H */
diff -puN include/asm-i386/pgtable.h~kprobes-mark-ro-data-fix-i386
include/asm-i386/pgtable.h
--- linux-2.6.22-rc2/include/asm-i386/pgtable.h~kprobes-mark-ro-data-fix-i386
2007-06-07 09:19:26.0 +0530
+++
Re: [PATCH] Kprobes x86_64 fix for mark ro data
This patch fixes the problem of page protection introduced by
CONFIG_DEBUG_RODATA for x86_64 architecture. As per Andi
Kleen's suggestion, the kernel text pages are marked writeable
only for a short duration to insert or remove the breakpoints.
Signed-off-by: Prasanna S P[EMAIL PROTECTED]
Ack-ed-by: Jim Keniston [EMAIL PROTECTED]
arch/x86_64/kernel/kprobes.c | 26 ++
arch/x86_64/mm/init.c|6 +-
include/asm-x86_64/kprobes.h | 10 ++
3 files changed, 41 insertions(+), 1 deletion(-)
diff -puN arch/x86_64/kernel/kprobes.c~kprobes-mark-ro-data-fix-x86_64
arch/x86_64/kernel/kprobes.c
---
linux-2.6.22-rc2/arch/x86_64/kernel/kprobes.c~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/x86_64/kernel/kprobes.c 2007-06-07
09:20:33.0 +0530
@@ -209,16 +209,42 @@ static void __kprobes arch_copy_kprobe(s
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long)p-addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
+ global_flush_tlb();
+ page_readonly = 1;
+ }
*p-addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p-addr,
(unsigned long) p-addr + sizeof(kprobe_opcode_t));
+ if (page_readonly) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
+ global_flush_tlb();
+ }
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
+ unsigned long addr = (unsigned long)p-addr;
+ int page_readonly = 0;
+
+ if (kernel_readonly_text(addr)) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
+ global_flush_tlb();
+ page_readonly = 1;
+ }
+
*p-addr = p-opcode;
flush_icache_range((unsigned long) p-addr,
(unsigned long) p-addr + sizeof(kprobe_opcode_t));
+
+ if (page_readonly) {
+ change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
+ global_flush_tlb();
+ }
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff -puN include/asm-x86_64/kprobes.h~kprobes-mark-ro-data-fix-x86_64
include/asm-x86_64/kprobes.h
---
linux-2.6.22-rc2/include/asm-x86_64/kprobes.h~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/include/asm-x86_64/kprobes.h 2007-06-07
09:20:33.0 +0530
@@ -26,6 +26,7 @@
#include linux/types.h
#include linux/ptrace.h
#include linux/percpu.h
+#include asm-generic/sections.h
#define __ARCH_WANT_KPROBES_INSN_SLOT
@@ -88,4 +89,13 @@ extern int kprobe_handler(struct pt_regs
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kernel_text_is_ro;
+static inline int kernel_readonly_text(unsigned long address)
+{
+ if (kernel_text_is_ro ((address = (unsigned long)_stext)
+(address (unsigned long) _etext)))
+ return 1;
+
+ return 0;
+}
#endif /* _ASM_KPROBES_H */
diff -puN arch/x86_64/mm/init.c~kprobes-mark-ro-data-fix-x86_64
arch/x86_64/mm/init.c
--- linux-2.6.22-rc2/arch/x86_64/mm/init.c~kprobes-mark-ro-data-fix-x86_64
2007-06-07 09:20:33.0 +0530
+++ linux-2.6.22-rc2-prasanna/arch/x86_64/mm/init.c 2007-06-07
09:20:33.0 +0530
@@ -48,6 +48,7 @@
#define Dprintk(x...)
#endif
+int kernel_text_is_ro;
const struct dma_mapping_ops* dma_ops;
EXPORT_SYMBOL(dma_ops);
@@ -598,10 +599,13 @@ void mark_rodata_ro(void)
{
unsigned long start = (unsigned long)_stext, end;
+ kernel_text_is_ro = 1;
#ifdef CONFIG_HOTPLUG_CPU
/* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() 1)
+ if (num_possible_cpus() 1) {
start = (unsigned long)_etext;
+ kernel_text_is_ro = 0;
+ }
#endif
end = (unsigned long)__end_rodata;
start = (start + PAGE_SIZE - 1) PAGE_MASK;
_
--
Prasanna S.P.
Linux Technology Center
India Software Labs, IBM Bangalore
Email: [EMAIL PROTECTED]
Ph: 91-80-41776329
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Kwatch: kernel watchpoints using CPU debug registers
On Wed, Feb 21, 2007 at 03:35:13PM -0500, Alan Stern wrote: > Going back to something you mentioned earlier... > [...] > On Fri, 9 Feb 2007, Roland McGrath wrote: > There are two things I am uncertain about: vm86 mode and kprobes. I don't > know anything about how either of them works. Judging from the current > code, nothing much should be needed -- debug traps in vm86 mode are > handled by calling handle_vm86_trap(), and kprobes puts itself at the > start of the notify_die() chain so it can handle single-step traps. > Eventually it will be necessary to check with someone who really > understands the issues. Yes, Kprobes needs to get notified first to handle single-step traps. So kwatch getting notified secound should be fine. Thanks Prasanna -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Kwatch: kernel watchpoints using CPU debug registers
On Wed, Feb 21, 2007 at 03:35:13PM -0500, Alan Stern wrote: Going back to something you mentioned earlier... [...] On Fri, 9 Feb 2007, Roland McGrath wrote: There are two things I am uncertain about: vm86 mode and kprobes. I don't know anything about how either of them works. Judging from the current code, nothing much should be needed -- debug traps in vm86 mode are handled by calling handle_vm86_trap(), and kprobes puts itself at the start of the notify_die() chain so it can handle single-step traps. Eventually it will be necessary to check with someone who really understands the issues. Yes, Kprobes needs to get notified first to handle single-step traps. So kwatch getting notified secound should be fine. Thanks Prasanna -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 0/4 update] kprobes and traps
On Tue, Jan 16, 2007 at 04:27:40PM -0500, Mathieu Desnoyers wrote: > Hi, > > I have looked at kprobes code and have some questions for you. I would really > like to use it to patch dynamically my marker immediate value by doing code > patching. Using an int3 seems like the right way to handle this wrt pIII > erratum > 49. > > Everything is ok, except for a limitation important to the LTTng project : > kprobes cannot probe trap handlers. Looking at the code, I see that the > kprobes > trap notifier expects interrupts to be disabled when it is run. Looking a > little > deeper in the code, I notice that you use per-cpu data structures to keep the > probe control information that is needed for single stepping, which clearly > requires you to disable interrupts so no interrupt handler with a kprobe in it > fires on top of the kprobe handler. It also forbids trap handler and NMI > handler instrumentation, as traps can be triggered by the kprobes handler and > NMIs can come at any point during execution. >From i386 point of view, your understanding is correct. > > Would it be possible to put these data structures on the stack or on a > separate stack accessible through thread_info instead ? > Yes, probably you can put them on per thread kernel stack. But you need to find enough stack space to save the probe control information. Also enough stack space should be allocated to handle re-entrant kprobe handlers. How will you handle the case where in nested interrupts happen while you are in a the kprobe handler and those interrupt handlers have probes. How many levels of nesting will you allow? Regards Prasanna > > > * Mathieu Desnoyers ([EMAIL PROTECTED]) wrote: > > Hi Richard, > > > > * Mathieu Desnoyers ([EMAIL PROTECTED]) wrote: > > > > You've got the same optimizations for x86 by modifying an instruction's > > > > immediate operand and thus avoiding a d-cache hit. The only real caveat > > > > is > > > > the need to avoid the unsynchronised cross modification erratum. Which > > > > means that all processors will need to issue a serializing operation > > > > before > > > > executing a Marker whose state is changed. How is that handled? > > > > > > > > > > Good catch. I thought that modifying only 1 byte would spare us from this > > > errata, but looking at it in detail tells me than it's not the case. > > > > > > I see three different ways to address the problem : > > [...] > > > 3 - First write an int3 instead of the instruction's first byte. The > > > handler > > > would do the following : > > > int3_handler : > > > single-step the original instruction. > > > iret > > > > > > Secondly, we call an IPI that does a smp_processor_id() on each CPU > > > and > > > wait for them to complete. It will make sure we execute a > > > synchronizing > > > instruction on every CPU even if we do not execute the trap handler. > > > > > > Then, we write the new 2 bytes instruction atomically instead of the > > > int3 > > > and immediate value. > > > > > > > > > > Here is the implementation of my proposal using a slightly enhanced > > kprobes. I > > add the ability to single step a different instruction than the original > > one, > > and then put the new instruction instead of the original one when removing > > the > > kprobe. It is an improvement on the djprobes design : AFAIK, djprobes > > required > > the int3 to be executed by _every_ CPU before the instruction could be > > replaced. It was problematic with rarely used code paths (error handling) > > and > > with thread CPU affinity. Comments are welcome. > > > > I noticed that it restrains LTTng by removing the ability to probe > > do_general_protection, do_nmi, do_trap, do_debug and do_page_fault. > > hardirq on/off in lockdep.c must also be tweaked to allow > > local_irq_enable/disable usage within the debug trap handler. > > > > It would be nice to push the study of the kprobes debug trap handler so it > > can > > become possible to use it to put breakpoints in trap handlers. For now, > > kprobes > > refuses to insert breakpoints in __kprobes marked functions. However, as we > > instrument specific spots of the functions (not necessarily the function > > entry), > > it is sometimes correct to use kprobes on a marker within the function even > > if > > it is not correct to use it in the prologue. Insight from the SystemTAP team > > would be welcome on this kprobe limitation. > > > > Mathieu > > > > Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]> > > > > --- a/arch/i386/kernel/kprobes.c > > +++ b/arch/i386/kernel/kprobes.c > > @@ -31,6 +31,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -753,6 +754,73 @@ int __kprobes longjmp_break_handler(struct kprobe *p, > > struct pt_regs *regs) > > return 0; > > } > > > > +static struct kprobe xmc_kp; > >
Re: [PATCH 0/4 update] kprobes and traps
On Tue, Jan 16, 2007 at 04:27:40PM -0500, Mathieu Desnoyers wrote:
Hi,
I have looked at kprobes code and have some questions for you. I would really
like to use it to patch dynamically my marker immediate value by doing code
patching. Using an int3 seems like the right way to handle this wrt pIII
erratum
49.
Everything is ok, except for a limitation important to the LTTng project :
kprobes cannot probe trap handlers. Looking at the code, I see that the
kprobes
trap notifier expects interrupts to be disabled when it is run. Looking a
little
deeper in the code, I notice that you use per-cpu data structures to keep the
probe control information that is needed for single stepping, which clearly
requires you to disable interrupts so no interrupt handler with a kprobe in it
fires on top of the kprobe handler. It also forbids trap handler and NMI
handler instrumentation, as traps can be triggered by the kprobes handler and
NMIs can come at any point during execution.
From i386 point of view, your understanding is correct.
Would it be possible to put these data structures on the stack or on a
separate stack accessible through thread_info instead ?
Yes, probably you can put them on per thread kernel stack.
But you need to find enough stack space to save the probe control
information. Also enough stack space should be allocated to handle
re-entrant kprobe handlers.
How will you handle the case where in nested interrupts happen while you
are in a the kprobe handler and those interrupt handlers have probes.
How many levels of nesting will you allow?
Regards
Prasanna
* Mathieu Desnoyers ([EMAIL PROTECTED]) wrote:
Hi Richard,
* Mathieu Desnoyers ([EMAIL PROTECTED]) wrote:
You've got the same optimizations for x86 by modifying an instruction's
immediate operand and thus avoiding a d-cache hit. The only real caveat
is
the need to avoid the unsynchronised cross modification erratum. Which
means that all processors will need to issue a serializing operation
before
executing a Marker whose state is changed. How is that handled?
Good catch. I thought that modifying only 1 byte would spare us from this
errata, but looking at it in detail tells me than it's not the case.
I see three different ways to address the problem :
[...]
3 - First write an int3 instead of the instruction's first byte. The
handler
would do the following :
int3_handler :
single-step the original instruction.
iret
Secondly, we call an IPI that does a smp_processor_id() on each CPU
and
wait for them to complete. It will make sure we execute a
synchronizing
instruction on every CPU even if we do not execute the trap handler.
Then, we write the new 2 bytes instruction atomically instead of the
int3
and immediate value.
Here is the implementation of my proposal using a slightly enhanced
kprobes. I
add the ability to single step a different instruction than the original
one,
and then put the new instruction instead of the original one when removing
the
kprobe. It is an improvement on the djprobes design : AFAIK, djprobes
required
the int3 to be executed by _every_ CPU before the instruction could be
replaced. It was problematic with rarely used code paths (error handling)
and
with thread CPU affinity. Comments are welcome.
I noticed that it restrains LTTng by removing the ability to probe
do_general_protection, do_nmi, do_trap, do_debug and do_page_fault.
hardirq on/off in lockdep.c must also be tweaked to allow
local_irq_enable/disable usage within the debug trap handler.
It would be nice to push the study of the kprobes debug trap handler so it
can
become possible to use it to put breakpoints in trap handlers. For now,
kprobes
refuses to insert breakpoints in __kprobes marked functions. However, as we
instrument specific spots of the functions (not necessarily the function
entry),
it is sometimes correct to use kprobes on a marker within the function even
if
it is not correct to use it in the prologue. Insight from the SystemTAP team
would be welcome on this kprobe limitation.
Mathieu
Signed-off-by: Mathieu Desnoyers [EMAIL PROTECTED]
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -31,6 +31,7 @@
#include linux/kprobes.h
#include linux/ptrace.h
#include linux/preempt.h
+#include linux/kallsyms.h
#include asm/cacheflush.h
#include asm/kdebug.h
#include asm/desc.h
@@ -753,6 +754,73 @@ int __kprobes longjmp_break_handler(struct kprobe *p,
struct pt_regs *regs)
return 0;
}
+static struct kprobe xmc_kp;
+DEFINE_MUTEX(kprobe_xmc_mutex);
+
+static int xmc_handler_pre(struct kprobe *p, struct pt_regs *regs)
+{
+ return 0;
+}
+
+static
Re: Kwatch patch available for 2.6.20?
On Sun, Jan 07, 2007 at 01:00:08PM -0500, Alan Stern wrote: > Has the kwatch patch (hardware watchpooint debugging for x86) been updated > to the current kernel? Is it available anywhere? Hi Alan, On Sun, Jan 07, 2007 at 01:00:08PM -0500, Alan Stern wrote: > Has the kwatch patch (hardware watchpooint debugging for x86) been updated > to the current kernel? Is it available anywhere? Currently kwatch patches are for 2.6.13 kernel. Please find the watchpoint probe patches in URL below. http://lkml.org/lkml/2005/8/30/57 http://lkml.org/lkml/2005/8/30/48 These patches were posted on lkml sometime back. Please let me know if you need any help. Thanks Prasanna > > Thank you, > > Alan Stern -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Kwatch patch available for 2.6.20?
On Sun, Jan 07, 2007 at 01:00:08PM -0500, Alan Stern wrote: Has the kwatch patch (hardware watchpooint debugging for x86) been updated to the current kernel? Is it available anywhere? Hi Alan, On Sun, Jan 07, 2007 at 01:00:08PM -0500, Alan Stern wrote: Has the kwatch patch (hardware watchpooint debugging for x86) been updated to the current kernel? Is it available anywhere? Currently kwatch patches are for 2.6.13 kernel. Please find the watchpoint probe patches in URL below. http://lkml.org/lkml/2005/8/30/57 http://lkml.org/lkml/2005/8/30/48 These patches were posted on lkml sometime back. Please let me know if you need any help. Thanks Prasanna Thank you, Alan Stern -- Prasanna S.P. Linux Technology Center India Software Labs, IBM Bangalore Email: [EMAIL PROTECTED] Ph: 91-80-41776329 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
