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author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-01-08 23:58:09 +0900 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-01-14 08:38:05 +0100 |
commit | 5b485629ba0d5d027880769ff467c587b24b4bde (patch) | |
tree | 395ec5583989fd297007dfd2c7d04292ed273242 /include/linux/kprobes.h | |
parent | f913f3a655cb4c37129bb36c9f175071e1fbdc29 (diff) | |
download | linux-5b485629ba0d5d027880769ff467c587b24b4bde.tar.gz linux-5b485629ba0d5d027880769ff467c587b24b4bde.tar.bz2 linux-5b485629ba0d5d027880769ff467c587b24b4bde.zip |
kprobes, extable: Identify kprobes trampolines as kernel text area
Improve __kernel_text_address()/kernel_text_address() to return
true if the given address is on a kprobe's instruction slot
trampoline.
This can help stacktraces to determine the address is on a
text area or not.
To implement this atomically in is_kprobe_*_slot(), also change
the insn_cache page list to an RCU list.
This changes timings a bit (it delays page freeing to the RCU garbage
collection phase), but none of that is in the hot path.
Note: this change can add small overhead to stack unwinders because
it adds 2 additional checks to __kernel_text_address(). However, the
impact should be very small, because kprobe_insn_pages list has 1 entry
per 256 probes(on x86, on arm/arm64 it will be 1024 probes),
and kprobe_optinsn_pages has 1 entry per 32 probes(on x86).
In most use cases, the number of kprobe events may be less
than 20, which means that is_kprobe_*_slot() will check just one entry.
Tested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/148388747896.6869.6354262871751682264.stgit@devbox
[ Improved the changelog and coding style. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/kprobes.h')
-rw-r--r-- | include/linux/kprobes.h | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 8f6849084248..16ddfb8b304a 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -278,9 +278,13 @@ struct kprobe_insn_cache { int nr_garbage; }; +#ifdef __ARCH_WANT_KPROBES_INSN_SLOT extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); extern void __free_insn_slot(struct kprobe_insn_cache *c, kprobe_opcode_t *slot, int dirty); +/* sleep-less address checking routine */ +extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c, + unsigned long addr); #define DEFINE_INSN_CACHE_OPS(__name) \ extern struct kprobe_insn_cache kprobe_##__name##_slots; \ @@ -294,6 +298,18 @@ static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ { \ __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ } \ + \ +static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ +{ \ + return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \ +} +#else /* __ARCH_WANT_KPROBES_INSN_SLOT */ +#define DEFINE_INSN_CACHE_OPS(__name) \ +static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ +{ \ + return 0; \ +} +#endif DEFINE_INSN_CACHE_OPS(insn); @@ -330,7 +346,6 @@ extern int proc_kprobes_optimization_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos); #endif - #endif /* CONFIG_OPTPROBES */ #ifdef CONFIG_KPROBES_ON_FTRACE extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, @@ -481,6 +496,19 @@ static inline int enable_jprobe(struct jprobe *jp) return enable_kprobe(&jp->kp); } +#ifndef CONFIG_KPROBES +static inline bool is_kprobe_insn_slot(unsigned long addr) +{ + return false; +} +#endif +#ifndef CONFIG_OPTPROBES +static inline bool is_kprobe_optinsn_slot(unsigned long addr) +{ + return false; +} +#endif + #ifdef CONFIG_KPROBES /* * Blacklist ganerating macro. Specify functions which is not probed |