| Message ID | 1420616124-42765-1-git-send-email-wangnan0@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/07/2015 02:35 AM, Wang Nan wrote: > If kprobe is optimized before kprobe is initialized, there should > be only one core, the probed instruction is not armed with breakpoint, > so simply patch text is okay. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > --- > arch/arm/probes/kprobes/opt-arm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c > index 15b37c0..a021474 100644 > --- a/arch/arm/probes/kprobes/opt-arm.c > +++ b/arch/arm/probes/kprobes/opt-arm.c > @@ -325,8 +325,17 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) > * Similar to __arch_disarm_kprobe, operations which > * removing breakpoints must be wrapped by stop_machine > * to avoid racing. > + * > + * If this function is called before kprobes initialized, > + * the kprobe should be an early kprobe, the instruction > + * is not armed with breakpoint. There should be only > + * one core now, so directly __patch_text is enough. > */ > - kprobes_remove_breakpoint(op->kp.addr, insn); > + if (unlikely(!kprobes_initialized)) { > + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); > + __patch_text(op->kp.addr, insn); > + } else > + kprobes_remove_breakpoint(op->kp.addr, insn); "...if only one branch of a conditional statement is a single statement ... use braces in both branches". https://www.kernel.org/doc/Documentation/CodingStyle > > list_del_init(&op->list); > } > Regards, Chris
(2015/01/07 16:35), Wang Nan wrote: > If kprobe is optimized before kprobe is initialized, there should > be only one core, the probed instruction is not armed with breakpoint, > so simply patch text is okay. This patch looks very hacky. If kprobes is not initialized, why anyone can optimize kprobes? I think you must introduce early kprobes init routine and set init flag at that point. Thank you, > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > --- > arch/arm/probes/kprobes/opt-arm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c > index 15b37c0..a021474 100644 > --- a/arch/arm/probes/kprobes/opt-arm.c > +++ b/arch/arm/probes/kprobes/opt-arm.c > @@ -325,8 +325,17 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) > * Similar to __arch_disarm_kprobe, operations which > * removing breakpoints must be wrapped by stop_machine > * to avoid racing. > + * > + * If this function is called before kprobes initialized, > + * the kprobe should be an early kprobe, the instruction > + * is not armed with breakpoint. There should be only > + * one core now, so directly __patch_text is enough. > */ > - kprobes_remove_breakpoint(op->kp.addr, insn); > + if (unlikely(!kprobes_initialized)) { > + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); > + __patch_text(op->kp.addr, insn); > + } else > + kprobes_remove_breakpoint(op->kp.addr, insn); > > list_del_init(&op->list); > } >
diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index 15b37c0..a021474 100644 --- a/arch/arm/probes/kprobes/opt-arm.c +++ b/arch/arm/probes/kprobes/opt-arm.c @@ -325,8 +325,17 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) * Similar to __arch_disarm_kprobe, operations which * removing breakpoints must be wrapped by stop_machine * to avoid racing. + * + * If this function is called before kprobes initialized, + * the kprobe should be an early kprobe, the instruction + * is not armed with breakpoint. There should be only + * one core now, so directly __patch_text is enough. */ - kprobes_remove_breakpoint(op->kp.addr, insn); + if (unlikely(!kprobes_initialized)) { + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); + __patch_text(op->kp.addr, insn); + } else + kprobes_remove_breakpoint(op->kp.addr, insn); list_del_init(&op->list); }
If kprobe is optimized before kprobe is initialized, there should be only one core, the probed instruction is not armed with breakpoint, so simply patch text is okay. Signed-off-by: Wang Nan <wangnan0@huawei.com> --- arch/arm/probes/kprobes/opt-arm.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)