* [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code
@ 2017-07-25 14:54 Masami Hiramatsu
2017-07-25 23:58 ` Masami Hiramatsu
2017-07-27 15:29 ` kbuild test robot
0 siblings, 2 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2017-07-25 14:54 UTC (permalink / raw)
To: Ingo Molnar
Cc: Francis Deslauriers, mathieu.desnoyers, Thomas Gleixner,
Ingo Molnar, H . Peter Anvin, x86, Masami Hiramatsu,
Ananth N Mavinakayanahalli, Anil S Keshavamurthy,
David S . Miller, linux-kernel
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.
*/
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code
2017-07-25 14:54 [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code Masami Hiramatsu
@ 2017-07-25 23:58 ` Masami Hiramatsu
2017-07-27 15:29 ` kbuild test robot
1 sibling, 0 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2017-07-25 23:58 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Ingo Molnar, Francis Deslauriers, mathieu.desnoyers,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, x86,
Ananth N Mavinakayanahalli, Anil S Keshavamurthy,
David S . Miller, linux-kernel
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code
2017-07-25 14:54 [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code Masami Hiramatsu
2017-07-25 23:58 ` Masami Hiramatsu
@ 2017-07-27 15:29 ` kbuild test robot
1 sibling, 0 replies; 3+ messages in thread
From: kbuild test robot @ 2017-07-27 15:29 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: kbuild-all, Ingo Molnar, Francis Deslauriers, mathieu.desnoyers,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, x86,
Masami Hiramatsu, Ananth N Mavinakayanahalli,
Anil S Keshavamurthy, David S . Miller, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1330 bytes --]
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
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 19474 bytes --]
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2017-07-25 14:54 [PATCH -tip V3] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code Masami Hiramatsu
2017-07-25 23:58 ` Masami Hiramatsu
2017-07-27 15:29 ` kbuild test robot
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