Patch 4/5 is from arm64’s KPROBES_ON_FTRACE, I think which is needed by all RISC with both KPROBES_ON_FTRACE and -fpatchable-function-entry. But since V7, no further patches are released, what protocol should I follow if I need these two patches? > On Mar 26, 2021, at 3:44 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > On Sat, 13 Mar 2021 14:41:47 +0800 > Huang Pei <huangpei@xxxxxxxxxxx> wrote: > >> From: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx> >> > > Looks like this was sent before, but was missing the proper authorship > (which is not Jisheng). > > https://lore.kernel.org/linux-arm-kernel/20191225173219.4f9db436@xhacker.debian/ > > -- Steve > > >> Ftrace location could include more than a single instruction in case >> of some architectures (powerpc64, for now). In this case, kprobe is >> permitted on any of those instructions, and uses ftrace infrastructure >> for functioning. >> >> However, [dis]arm_kprobe_ftrace() uses the kprobe address when setting >> up ftrace filter IP. This won't work if the address points to any >> instruction apart from the one that has a branch to _mcount(). To >> resolve this, have [dis]arm_kprobe_ftrace() use ftrace_function() to >> identify the filter IP. >> >> Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> >> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> >> --- >> kernel/kprobes.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/kprobes.c b/kernel/kprobes.c >> index 41fdbb7953c6..66ee28b071c2 100644 >> --- a/kernel/kprobes.c >> +++ b/kernel/kprobes.c >> @@ -1045,9 +1045,10 @@ static int prepare_kprobe(struct kprobe *p) >> static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, >> int *cnt) >> { >> + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); >> int ret = 0; >> >> - ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); >> + ret = ftrace_set_filter_ip(ops, ftrace_ip, 0, 0); >> if (ret) { >> pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", >> p->addr, ret); >> @@ -1070,7 +1071,7 @@ static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, >> * At this point, sinec ops is not registered, we should be sefe from >> * registering empty filter. >> */ >> - ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); >> + ftrace_set_filter_ip(ops, ftrace_ip, 1, 0); >> return ret; >> } >> >> @@ -1087,6 +1088,7 @@ static int arm_kprobe_ftrace(struct kprobe *p) >> static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, >> int *cnt) >> { >> + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); >> int ret = 0; >> >> if (*cnt == 1) { >> @@ -1097,7 +1099,7 @@ static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, >> >> (*cnt)--; >> >> - ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); >> + ret = ftrace_set_filter_ip(ops, ftrace_ip, 1, 0); >> WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", >> p->addr, ret); >> return ret; Huang Pei huangpei@xxxxxxxxxxx
