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Groups > linux.kernel > #1695812 > unrolled thread
| Started by | Masami Hiramatsu <mhiramat@kernel.org> |
|---|---|
| First post | 2017-07-25 17:00 +0200 |
| Last post | 2017-07-27 17:40 +0200 |
| Articles | 3 — 2 participants |
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[PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code Masami Hiramatsu <mhiramat@kernel.org> - 2017-07-25 17:00 +0200
Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code Masami Hiramatsu <mhiramat@kernel.org> - 2017-07-26 02:00 +0200
Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code kbuild test robot <lkp@intel.com> - 2017-07-27 17:40 +0200
| From | Masami Hiramatsu <mhiramat@kernel.org> |
|---|---|
| Date | 2017-07-25 17:00 +0200 |
| Subject | [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code |
| Message-ID | <u79tw-45h-15@gated-at.bofh.it> |
Since the kernel segment registers are not prepared at the entry of irq-entry code, if a kprobe on such code is jump-optimized, accessing per-cpu variables may cause kernel panic. However, if the kprobe is not optimized, it kicks int3 exception and set segment registers correctly. This checks probe-address and if it is in irq-entry code, it prohibits optimizing such kprobes. This means we can continuously probing such interrupt handlers by kprobes but it is not optimized anymore. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com> Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com> --- Changes in V3: - Define __irqentry_text_start/end symbols when CONFIG_OPTPROBES=y. --- arch/x86/kernel/kprobes/opt.c | 9 ++++++--- include/asm-generic/vmlinux.lds.h | 6 ++++-- include/linux/interrupt.h | 3 ++- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 69ea0bc..c26e7f9 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -29,6 +29,7 @@ #include <linux/kallsyms.h> #include <linux/ftrace.h> #include <linux/frame.h> +#include <linux/interrupt.h> #include <asm/text-patching.h> #include <asm/cacheflush.h> @@ -251,10 +252,12 @@ static int can_optimize(unsigned long paddr) /* * Do not optimize in the entry code due to the unstable - * stack handling. + * stack handling and registers setup. */ - if ((paddr >= (unsigned long)__entry_text_start) && - (paddr < (unsigned long)__entry_text_end)) + if (((paddr >= (unsigned long)__entry_text_start) && + (paddr < (unsigned long)__entry_text_end)) || + ((paddr >= (unsigned long)__irqentry_text_start) && + (paddr < (unsigned long)__irqentry_text_end))) return 0; /* Check there is enough space for a relative jump. */ diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index da0be9a..3092a1f 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -483,7 +483,8 @@ *(.entry.text) \ VMLINUX_SYMBOL(__entry_text_end) = .; -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ + defined(CONFIG_OPTPROBES) #define IRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__irqentry_text_start) = .; \ @@ -493,7 +494,8 @@ #define IRQENTRY_TEXT #endif -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ + defined(CONFIG_OPTPROBES) #define SOFTIRQENTRY_TEXT \ ALIGN_FUNCTION(); \ VMLINUX_SYMBOL(__softirqentry_text_start) = .; \ diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index a2fdddd..a1b78f4 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -726,7 +726,8 @@ extern int early_irq_init(void); extern int arch_probe_nr_irqs(void); extern int arch_early_irq_init(void); -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ + defined(CONFIG_KPROBES) /* * We want to know which function is an entrypoint of a hardirq or a softirq. */
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| From | Masami Hiramatsu <mhiramat@kernel.org> |
|---|---|
| Date | 2017-07-26 02:00 +0200 |
| Subject | Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code |
| Message-ID | <u7hU5-15V-1@gated-at.bofh.it> |
| In reply to | #1695812 |
On Tue, 25 Jul 2017 23:54:49 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote: > Since the kernel segment registers are not prepared at the > entry of irq-entry code, if a kprobe on such code is > jump-optimized, accessing per-cpu variables may cause > kernel panic. > However, if the kprobe is not optimized, it kicks int3 > exception and set segment registers correctly. > > This checks probe-address and if it is in irq-entry code, > it prohibits optimizing such kprobes. This means we can > continuously probing such interrupt handlers by kprobes > but it is not optimized anymore. > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com> > Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com> > --- > Changes in V3: > - Define __irqentry_text_start/end symbols when CONFIG_OPTPROBES=y. > --- > arch/x86/kernel/kprobes/opt.c | 9 ++++++--- > include/asm-generic/vmlinux.lds.h | 6 ++++-- > include/linux/interrupt.h | 3 ++- > 3 files changed, 12 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c > index 69ea0bc..c26e7f9 100644 > --- a/arch/x86/kernel/kprobes/opt.c > +++ b/arch/x86/kernel/kprobes/opt.c > @@ -29,6 +29,7 @@ > #include <linux/kallsyms.h> > #include <linux/ftrace.h> > #include <linux/frame.h> > +#include <linux/interrupt.h> > > #include <asm/text-patching.h> > #include <asm/cacheflush.h> > @@ -251,10 +252,12 @@ static int can_optimize(unsigned long paddr) > > /* > * Do not optimize in the entry code due to the unstable > - * stack handling. > + * stack handling and registers setup. > */ > - if ((paddr >= (unsigned long)__entry_text_start) && > - (paddr < (unsigned long)__entry_text_end)) > + if (((paddr >= (unsigned long)__entry_text_start) && > + (paddr < (unsigned long)__entry_text_end)) || > + ((paddr >= (unsigned long)__irqentry_text_start) && > + (paddr < (unsigned long)__irqentry_text_end))) > return 0; > > /* Check there is enough space for a relative jump. */ > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index da0be9a..3092a1f 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -483,7 +483,8 @@ > *(.entry.text) \ > VMLINUX_SYMBOL(__entry_text_end) = .; > > -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) > +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ > + defined(CONFIG_OPTPROBES) > #define IRQENTRY_TEXT \ > ALIGN_FUNCTION(); \ > VMLINUX_SYMBOL(__irqentry_text_start) = .; \ > @@ -493,7 +494,8 @@ > #define IRQENTRY_TEXT > #endif > > -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) > +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ > + defined(CONFIG_OPTPROBES) > #define SOFTIRQENTRY_TEXT \ > ALIGN_FUNCTION(); \ > VMLINUX_SYMBOL(__softirqentry_text_start) = .; \ > diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h > index a2fdddd..a1b78f4 100644 > --- a/include/linux/interrupt.h > +++ b/include/linux/interrupt.h > @@ -726,7 +726,8 @@ extern int early_irq_init(void); > extern int arch_probe_nr_irqs(void); > extern int arch_early_irq_init(void); > > -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) > +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) || \ > + defined(CONFIG_KPROBES) Oops, this should be CONFIG_OPTPROBES... > /* > * We want to know which function is an entrypoint of a hardirq or a softirq. > */ > -- Masami Hiramatsu <mhiramat@kernel.org>
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| From | kbuild test robot <lkp@intel.com> |
|---|---|
| Date | 2017-07-27 17:40 +0200 |
| Subject | Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code |
| Message-ID | <u7T3k-7P8-17@gated-at.bofh.it> |
| In reply to | #1695812 |
[Multipart message — attachments visible in raw view] — view raw
Hi Masami,
[auto build test WARNING on tip/auto-latest]
[also build test WARNING on v4.13-rc2 next-20170727]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/kprobes-x86-Do-not-jump-optimize-kprobes-on-irq-entry-code/20170727-041957
config: powerpc-c2k_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=powerpc
All warnings (new ones prefixed by >>):
>> powerpc-linux-gnu-ld: warning: orphan section `.softirqentry.text' from `kernel/softirq.o' being placed in section `.softirqentry.text'.
>> powerpc-linux-gnu-ld: warning: orphan section `.softirqentry.text' from `kernel/softirq.o' being placed in section `.softirqentry.text'.
>> powerpc-linux-gnu-ld: warning: orphan section `.softirqentry.text' from `kernel/softirq.o' being placed in section `.softirqentry.text'.
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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