On 2015/3/2 22:25, Wang Nan wrote: > Newly introduced function kprobe_on_ftrace_get_old_insn() will be > called by ftrace when ftrace generating call instruction. It is for > retriving probed instructions which original nops are replaced by > kprobe. FTRACE_FL_EARLY_KPROBES bit in rec->flags is cleared, so after > calling kprobe_on_ftrace_get_old_insn() an ftrace record will not be > treated as early kprobed. > > Signed-off-by: Wang Nan <wangn...@huawei.com> > --- > include/linux/kprobes.h | 9 +++++++++ > kernel/kprobes.c | 34 ++++++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+) > > diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h > index 5a5290f..2d78bbb 100644 > --- a/include/linux/kprobes.h > +++ b/include/linux/kprobes.h > @@ -289,6 +289,8 @@ extern const unsigned char > *arch_kprobe_on_ftrace_get_old_insn(struct kprobe *kp > > extern void init_kprobes_on_ftrace(void); > extern bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec); > +extern const unsigned char *kprobe_on_ftrace_get_old_insn(struct dyn_ftrace > *rec, > + const unsigned char *ftrace_nop, unsigned char *dest, size_t > insn_size); > #else > static inline void init_kprobes_on_ftrace(void) > { > @@ -299,6 +301,13 @@ static inline bool kprobe_fix_ftrace_make_nop(struct > dyn_ftrace *_unused) > > return false; > } > + > +static inline const unsigned char * > +kprobe_on_ftrace_get_old_insn(struct dyn_ftrace *_unused, > + const unsigned char *ftrace_nop, unsigned char *_unused2, > size_t _unused3) > +{ > + return ftrace_nop; > +} > #endif // CONFIG_EARLY_KPROBES && CONFIG_KPROBES_ON_FTRACE > > #ifdef CONFIG_EARLY_KPROBES > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 20b6ab8..c504c1c 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -2623,6 +2623,40 @@ bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec) > return true; > } > > +/* NOTE: caller must ensure holding kprobe_mutex */ > +const unsigned char * > +kprobe_on_ftrace_get_old_insn(struct dyn_ftrace *rec, > + const unsigned char *ftrace_nop, > + unsigned char *dest, size_t insn_size) > +{ > + const unsigned char *ret; > + struct kprobe *kp; > + void *addr; > + > + if (!(rec->flags & FTRACE_FL_EARLY_KPROBES)) > + return ftrace_nop; > + > + addr = (void *)rec->ip; > + > + /* > + * Note that get_kprobe always get the kprobe on table, for it > + * KPROBE_FLAG_OPTIMIZED is reliable. > + */ > + kp = get_kprobe(addr); > + > + if (!kp || !(kp->flags & KPROBE_FLAG_FTRACE_EARLY)) { > + mutex_unlock(&kprobe_mutex);
This mutex_unlock() is buggy. I'll fix it in next version. > + return ftrace_nop; > + } > + > + ret = arch_kprobe_on_ftrace_get_old_insn(kp, ftrace_nop, > + dest, insn_size); > + > + /* Only give one chance for kprobe to retrive old insn. */ > + rec->flags &= ~FTRACE_FL_EARLY_KPROBES; > + return ret; > +} > + > void init_kprobes_on_ftrace(void) > { > kprobes_on_ftrace_initialized = true; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/