Re: [PATCH] x86: Use is_kprobe_fault to better match usage
* Harvey Harrison <[EMAIL PROTECTED]> wrote: > Currently the notify_page_fault helper is used to test it the page > fault was caused by a kprobe causing an early return from > do_page_fault. > > Change the name of the helper to is_kprobe_fault to match the usage > and remove the preempt_disable/enable pair around kprobe_running() > with an explicit test for preemption. The idea for this comes from a > patch by Quentin Barnes to kprobes.c > > Signed-off-by: Harvey Harrison <[EMAIL PROTECTED]> hm, this doesnt apply: Hunk #3 FAILED at 426. Hunk #4 succeeded at 413 (offset -22 lines). 1 out of 4 hunks FAILED -- rejects in file arch/x86/mm/fault_32.c patching file arch/x86/mm/fault_64.c Hunk #3 FAILED at 476. Hunk #4 succeeded at 475 (offset -10 lines). 1 out of 4 hunks FAILED -- rejects in file arch/x86/mm/fault_64.c could you double-check x86.git#mm, perhaps we are out of sync with a patch somewhere? Ingo -- 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] x86: Use is_kprobe_fault to better match usage
* Harvey Harrison [EMAIL PROTECTED] wrote: Currently the notify_page_fault helper is used to test it the page fault was caused by a kprobe causing an early return from do_page_fault. Change the name of the helper to is_kprobe_fault to match the usage and remove the preempt_disable/enable pair around kprobe_running() with an explicit test for preemption. The idea for this comes from a patch by Quentin Barnes to kprobes.c Signed-off-by: Harvey Harrison [EMAIL PROTECTED] hm, this doesnt apply: Hunk #3 FAILED at 426. Hunk #4 succeeded at 413 (offset -22 lines). 1 out of 4 hunks FAILED -- rejects in file arch/x86/mm/fault_32.c patching file arch/x86/mm/fault_64.c Hunk #3 FAILED at 476. Hunk #4 succeeded at 475 (offset -10 lines). 1 out of 4 hunks FAILED -- rejects in file arch/x86/mm/fault_64.c could you double-check x86.git#mm, perhaps we are out of sync with a patch somewhere? Ingo -- 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] x86: Use is_kprobe_fault to better match usage
Harvey Harrison wrote: > On Wed, 2008-01-02 at 21:36 -0500, Masami Hiramatsu wrote: >> Hi Harvey, >> >> Harvey Harrison wrote: >>> Currently the notify_page_fault helper is used to test it the page >>> fault was caused by a kprobe causing an early return from do_page_fault. >>> >>> Change the name of the helper to is_kprobe_fault to match the usage and >>> remove the preempt_disable/enable pair around kprobe_running() with an >>> explicit test for preemption. The idea for this comes from a patch >>> by Quentin Barnes to kprobes.c >> Sure, that's right. >> However, since other architectures also have notify_page_fault(), >> I think all of those code might better be changed same time for >> maintainability. >> > > How about a static inline in linux/kprobes.h with a big comment above > about when/why the !preemptible() check is sufficient? Hmm, fault handling depends on the architecture. But current notify_page_fault()s are very similar. I think unifying it is good idea. We will be happy to review that if you send it. Many thanks! > > Harvey > > > -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: [EMAIL PROTECTED], [EMAIL PROTECTED] -- 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] x86: Use is_kprobe_fault to better match usage
On Wed, 2008-01-02 at 21:36 -0500, Masami Hiramatsu wrote: > Hi Harvey, > > Harvey Harrison wrote: > > Currently the notify_page_fault helper is used to test it the page > > fault was caused by a kprobe causing an early return from do_page_fault. > > > > Change the name of the helper to is_kprobe_fault to match the usage and > > remove the preempt_disable/enable pair around kprobe_running() with an > > explicit test for preemption. The idea for this comes from a patch > > by Quentin Barnes to kprobes.c > > Sure, that's right. > However, since other architectures also have notify_page_fault(), > I think all of those code might better be changed same time for > maintainability. > How about a static inline in linux/kprobes.h with a big comment above about when/why the !preemptible() check is sufficient? Harvey -- 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] x86: Use is_kprobe_fault to better match usage
Hi Harvey,
Harvey Harrison wrote:
> Currently the notify_page_fault helper is used to test it the page
> fault was caused by a kprobe causing an early return from do_page_fault.
>
> Change the name of the helper to is_kprobe_fault to match the usage and
> remove the preempt_disable/enable pair around kprobe_running() with an
> explicit test for preemption. The idea for this comes from a patch
> by Quentin Barnes to kprobes.c
Sure, that's right.
However, since other architectures also have notify_page_fault(),
I think all of those code might better be changed same time for
maintainability.
Thanks,
> Signed-off-by: Harvey Harrison <[EMAIL PROTECTED]>
> ---
> Ingo, this may not be functionally equivalent, feel free to yank it out
> if there is any trouble, but from what I've seen it should be OK.
>
> Did you ever find a good kprobes test?
>
> arch/x86/mm/fault_32.c | 30 ++
> arch/x86/mm/fault_64.c | 30 ++
> 2 files changed, 28 insertions(+), 32 deletions(-)
>
> diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
> index 051a4ec..5c48cc2 100644
> --- a/arch/x86/mm/fault_32.c
> +++ b/arch/x86/mm/fault_32.c
> @@ -12,6 +12,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -42,23 +43,20 @@
> #define PF_RSVD (1<<3)
> #define PF_INSTR (1<<4)
>
> -static inline int notify_page_fault(struct pt_regs *regs)
> +static inline int is_kprobe_fault(struct pt_regs *regs)
> {
> -#ifdef CONFIG_KPROBES
> int ret = 0;
> -
> - /* kprobe_running() needs smp_processor_id() */
> - if (!user_mode_vm(regs)) {
> - preempt_disable();
> - if (kprobe_running() && kprobe_fault_handler(regs, 14))
> - ret = 1;
> - preempt_enable();
> - }
> -
> - return ret;
> -#else
> - return 0;
> +#ifdef CONFIG_KPROBES
> + /*
> + * If it is a kprobe fault we can not be premptible so return before
> + * calling kprobe_running() as it will assert on smp_processor_id if
> + * preemption is enabled.
> + */
> + if (!user_mode_vm(regs) && !preemptible() && kprobe_running() &&
> + kprobe_fault_handler(regs, 14))
> + ret = 1;
> #endif
> + return ret;
> }
>
> #ifdef CONFIG_X86_32
> @@ -428,7 +426,7 @@ void __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long error_code)
> return;
> }
> #endif
> - if (notify_page_fault(regs))
> + if (is_kprobe_fault(regs))
> return;
> /*
>* Don't take the mm semaphore here. If we fixup a prefetch
> @@ -437,7 +435,7 @@ void __kprobes do_page_fault(struct pt_regs *regs,
> unsigned long error_code)
> goto bad_area_nosemaphore;
> }
>
> - if (notify_page_fault(regs))
> + if (is_kprobe_fault(regs))
> return;
>
> /* It's safe to allow irq's after cr2 has been saved and the vmalloc
> diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
> index 97b92b6..09008e5 100644
> --- a/arch/x86/mm/fault_64.c
> +++ b/arch/x86/mm/fault_64.c
> @@ -13,6 +13,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -45,23 +46,20 @@
> #define PF_RSVD (1<<3)
> #define PF_INSTR (1<<4)
>
> -static inline int notify_page_fault(struct pt_regs *regs)
> +static inline int is_kprobe_fault(struct pt_regs *regs)
> {
> -#ifdef CONFIG_KPROBES
> int ret = 0;
> -
> - /* kprobe_running() needs smp_processor_id() */
> - if (!user_mode(regs)) {
> - preempt_disable();
> - if (kprobe_running() && kprobe_fault_handler(regs, 14))
> - ret = 1;
> - preempt_enable();
> - }
> -
> - return ret;
> -#else
> - return 0;
> +#ifdef CONFIG_KPROBES
> + /*
> + * If it is a kprobe fault we can not be premptible so return before
> + * calling kprobe_running() as it will assert on smp_processor_id if
> + * preemption is enabled.
> + */
> + if (!user_mode_vm(regs) && !preemptible() && kprobe_running() &&
> + kprobe_fault_handler(regs, 14))
> + ret = 1;
> #endif
> + return ret;
> }
>
> #ifdef CONFIG_X86_32
> @@ -478,7 +476,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs
> *regs,
> return;
> }
> #endif
> - if (notify_page_fault(regs))
> + if (is_kprobe_fault(regs))
> return;
> /*
>* Don't take the mm semaphore here. If we fixup a prefetch
> @@ -487,7 +485,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs
> *regs,
> goto bad_area_nosemaphore;
> }
>
> - if (notify_page_fault(regs))
> + if (is_kprobe_fault(regs))
> return;
>
> if
Re: [PATCH] x86: Use is_kprobe_fault to better match usage
Hi Harvey,
Harvey Harrison wrote:
Currently the notify_page_fault helper is used to test it the page
fault was caused by a kprobe causing an early return from do_page_fault.
Change the name of the helper to is_kprobe_fault to match the usage and
remove the preempt_disable/enable pair around kprobe_running() with an
explicit test for preemption. The idea for this comes from a patch
by Quentin Barnes to kprobes.c
Sure, that's right.
However, since other architectures also have notify_page_fault(),
I think all of those code might better be changed same time for
maintainability.
Thanks,
Signed-off-by: Harvey Harrison [EMAIL PROTECTED]
---
Ingo, this may not be functionally equivalent, feel free to yank it out
if there is any trouble, but from what I've seen it should be OK.
Did you ever find a good kprobes test?
arch/x86/mm/fault_32.c | 30 ++
arch/x86/mm/fault_64.c | 30 ++
2 files changed, 28 insertions(+), 32 deletions(-)
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 051a4ec..5c48cc2 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -12,6 +12,7 @@
#include linux/mman.h
#include linux/mm.h
#include linux/smp.h
+#include linux/hardirq.h
#include linux/interrupt.h
#include linux/init.h
#include linux/tty.h
@@ -42,23 +43,20 @@
#define PF_RSVD (13)
#define PF_INSTR (14)
-static inline int notify_page_fault(struct pt_regs *regs)
+static inline int is_kprobe_fault(struct pt_regs *regs)
{
-#ifdef CONFIG_KPROBES
int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode_vm(regs)) {
- preempt_disable();
- if (kprobe_running() kprobe_fault_handler(regs, 14))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-#else
- return 0;
+#ifdef CONFIG_KPROBES
+ /*
+ * If it is a kprobe fault we can not be premptible so return before
+ * calling kprobe_running() as it will assert on smp_processor_id if
+ * preemption is enabled.
+ */
+ if (!user_mode_vm(regs) !preemptible() kprobe_running()
+ kprobe_fault_handler(regs, 14))
+ ret = 1;
#endif
+ return ret;
}
#ifdef CONFIG_X86_32
@@ -428,7 +426,7 @@ void __kprobes do_page_fault(struct pt_regs *regs,
unsigned long error_code)
return;
}
#endif
- if (notify_page_fault(regs))
+ if (is_kprobe_fault(regs))
return;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
@@ -437,7 +435,7 @@ void __kprobes do_page_fault(struct pt_regs *regs,
unsigned long error_code)
goto bad_area_nosemaphore;
}
- if (notify_page_fault(regs))
+ if (is_kprobe_fault(regs))
return;
/* It's safe to allow irq's after cr2 has been saved and the vmalloc
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index 97b92b6..09008e5 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -13,6 +13,7 @@
#include linux/mman.h
#include linux/mm.h
#include linux/smp.h
+#include linux/hardirq.h
#include linux/interrupt.h
#include linux/init.h
#include linux/tty.h
@@ -45,23 +46,20 @@
#define PF_RSVD (13)
#define PF_INSTR (14)
-static inline int notify_page_fault(struct pt_regs *regs)
+static inline int is_kprobe_fault(struct pt_regs *regs)
{
-#ifdef CONFIG_KPROBES
int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() kprobe_fault_handler(regs, 14))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-#else
- return 0;
+#ifdef CONFIG_KPROBES
+ /*
+ * If it is a kprobe fault we can not be premptible so return before
+ * calling kprobe_running() as it will assert on smp_processor_id if
+ * preemption is enabled.
+ */
+ if (!user_mode_vm(regs) !preemptible() kprobe_running()
+ kprobe_fault_handler(regs, 14))
+ ret = 1;
#endif
+ return ret;
}
#ifdef CONFIG_X86_32
@@ -478,7 +476,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs
*regs,
return;
}
#endif
- if (notify_page_fault(regs))
+ if (is_kprobe_fault(regs))
return;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
@@ -487,7 +485,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs
*regs,
goto bad_area_nosemaphore;
}
- if (notify_page_fault(regs))
+ if (is_kprobe_fault(regs))
return;
if (likely(regs-flags
Re: [PATCH] x86: Use is_kprobe_fault to better match usage
On Wed, 2008-01-02 at 21:36 -0500, Masami Hiramatsu wrote: Hi Harvey, Harvey Harrison wrote: Currently the notify_page_fault helper is used to test it the page fault was caused by a kprobe causing an early return from do_page_fault. Change the name of the helper to is_kprobe_fault to match the usage and remove the preempt_disable/enable pair around kprobe_running() with an explicit test for preemption. The idea for this comes from a patch by Quentin Barnes to kprobes.c Sure, that's right. However, since other architectures also have notify_page_fault(), I think all of those code might better be changed same time for maintainability. How about a static inline in linux/kprobes.h with a big comment above about when/why the !preemptible() check is sufficient? Harvey -- 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] x86: Use is_kprobe_fault to better match usage
Harvey Harrison wrote: On Wed, 2008-01-02 at 21:36 -0500, Masami Hiramatsu wrote: Hi Harvey, Harvey Harrison wrote: Currently the notify_page_fault helper is used to test it the page fault was caused by a kprobe causing an early return from do_page_fault. Change the name of the helper to is_kprobe_fault to match the usage and remove the preempt_disable/enable pair around kprobe_running() with an explicit test for preemption. The idea for this comes from a patch by Quentin Barnes to kprobes.c Sure, that's right. However, since other architectures also have notify_page_fault(), I think all of those code might better be changed same time for maintainability. How about a static inline in linux/kprobes.h with a big comment above about when/why the !preemptible() check is sufficient? Hmm, fault handling depends on the architecture. But current notify_page_fault()s are very similar. I think unifying it is good idea. We will be happy to review that if you send it. Many thanks! Harvey -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: [EMAIL PROTECTED], [EMAIL PROTECTED] -- 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/
