* [PATCH] tracing: precise log info for kretprobe addr err
@ 2021-01-19 15:10 Jianlin Lv
2021-01-19 15:41 ` Steven Rostedt
0 siblings, 1 reply; 4+ messages in thread
From: Jianlin Lv @ 2021-01-19 15:10 UTC (permalink / raw)
To: rostedt, mingo; +Cc: Jianlin.Lv, linux-kernel
When trying to create kretprobe with the wrong function symbol in tracefs;
The error is triggered in the register_trace_kprobe() and recorded as
FAIL_REG_PROBE issue,
Example:
$ cd /sys/kernel/debug/tracing
$ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
bash: echo: write error: Invalid argument
$ cat error_log
[142797.347877] trace_kprobe: error: Failed to register probe event
Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
^
This error can be detected in the parameter parsing stage, the effect of
applying this patch is as follows:
$ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
bash: echo: write error: Invalid argument
$ cat error_log
[415.89]trace_kprobe: error: Retprobe address must be an function entry
Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
^
Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
---
kernel/trace/trace_kprobe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index e6fba1798771..3dfd1b6711a3 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[])
flags |= TPARG_FL_RETURN;
if (kprobe_on_func_entry(NULL, symbol, offset))
flags |= TPARG_FL_FENTRY;
- if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
+ if (is_return && !(flags & TPARG_FL_FENTRY)) {
trace_probe_log_err(0, BAD_RETPROBE);
goto parse_error;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] tracing: precise log info for kretprobe addr err 2021-01-19 15:10 [PATCH] tracing: precise log info for kretprobe addr err Jianlin Lv @ 2021-01-19 15:41 ` Steven Rostedt 2021-01-20 3:24 ` Masami Hiramatsu 0 siblings, 1 reply; 4+ messages in thread From: Steven Rostedt @ 2021-01-19 15:41 UTC (permalink / raw) To: Masami Hiramatsu; +Cc: Jianlin Lv, mingo, linux-kernel Masami, Looks fine to me. What do you think? -- Steve On Tue, 19 Jan 2021 23:10:14 +0800 Jianlin Lv <Jianlin.Lv@arm.com> wrote: > When trying to create kretprobe with the wrong function symbol in tracefs; > The error is triggered in the register_trace_kprobe() and recorded as > FAIL_REG_PROBE issue, > > Example: > $ cd /sys/kernel/debug/tracing > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > bash: echo: write error: Invalid argument > $ cat error_log > [142797.347877] trace_kprobe: error: Failed to register probe event > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > ^ > > This error can be detected in the parameter parsing stage, the effect of > applying this patch is as follows: > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > bash: echo: write error: Invalid argument > $ cat error_log > [415.89]trace_kprobe: error: Retprobe address must be an function entry > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > ^ > > Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com> > --- > kernel/trace/trace_kprobe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > index e6fba1798771..3dfd1b6711a3 100644 > --- a/kernel/trace/trace_kprobe.c > +++ b/kernel/trace/trace_kprobe.c > @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) > flags |= TPARG_FL_RETURN; > if (kprobe_on_func_entry(NULL, symbol, offset)) > flags |= TPARG_FL_FENTRY; > - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { > + if (is_return && !(flags & TPARG_FL_FENTRY)) { > trace_probe_log_err(0, BAD_RETPROBE); > goto parse_error; > } ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tracing: precise log info for kretprobe addr err 2021-01-19 15:41 ` Steven Rostedt @ 2021-01-20 3:24 ` Masami Hiramatsu 2021-01-20 4:14 ` Masami Hiramatsu 0 siblings, 1 reply; 4+ messages in thread From: Masami Hiramatsu @ 2021-01-20 3:24 UTC (permalink / raw) To: Steven Rostedt; +Cc: Jianlin Lv, mingo, linux-kernel Hi, On Tue, 19 Jan 2021 10:41:06 -0500 Steven Rostedt <rostedt@goodmis.org> wrote: > Masami, > > Looks fine to me. What do you think? Agreed. Since register_kretprobe() checks the address by kprobe_on_func_entry(), if it is not passed, it should always fail to register at last. Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Thank you! > > -- Steve > > > On Tue, 19 Jan 2021 23:10:14 +0800 > Jianlin Lv <Jianlin.Lv@arm.com> wrote: > > > When trying to create kretprobe with the wrong function symbol in tracefs; > > The error is triggered in the register_trace_kprobe() and recorded as > > FAIL_REG_PROBE issue, > > > > Example: > > $ cd /sys/kernel/debug/tracing > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > bash: echo: write error: Invalid argument > > $ cat error_log > > [142797.347877] trace_kprobe: error: Failed to register probe event > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > ^ > > > > This error can be detected in the parameter parsing stage, the effect of > > applying this patch is as follows: > > > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > bash: echo: write error: Invalid argument > > $ cat error_log > > [415.89]trace_kprobe: error: Retprobe address must be an function entry > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > ^ > > > > Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com> > > --- > > kernel/trace/trace_kprobe.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index e6fba1798771..3dfd1b6711a3 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) > > flags |= TPARG_FL_RETURN; > > if (kprobe_on_func_entry(NULL, symbol, offset)) > > flags |= TPARG_FL_FENTRY; > > - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { > > + if (is_return && !(flags & TPARG_FL_FENTRY)) { > > trace_probe_log_err(0, BAD_RETPROBE); > > goto parse_error; > > } > -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tracing: precise log info for kretprobe addr err 2021-01-20 3:24 ` Masami Hiramatsu @ 2021-01-20 4:14 ` Masami Hiramatsu 0 siblings, 0 replies; 4+ messages in thread From: Masami Hiramatsu @ 2021-01-20 4:14 UTC (permalink / raw) To: Masami Hiramatsu; +Cc: Steven Rostedt, Jianlin Lv, mingo, linux-kernel On Wed, 20 Jan 2021 12:24:15 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote: > Hi, > > On Tue, 19 Jan 2021 10:41:06 -0500 > Steven Rostedt <rostedt@goodmis.org> wrote: > > > Masami, > > > > Looks fine to me. What do you think? > > Agreed. Since register_kretprobe() checks the address by kprobe_on_func_entry(), > if it is not passed, it should always fail to register at last. > > Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Oops, sorry I missed one case. Since kprobe_events can accept a symbol with module name (MOD:symbol) If the given symbol is on a module which is not loaded, kprobe_on_func_entry(NULL, symbol, offset) may return false too. (But that kretprobe must be enabled after the target module is loaded) To confirm it correctly, add !strchr(symbol, ':') there to check it is really bad symbol or not. diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 5fff39541b8a..0170f8e6430b 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) flags |= TPARG_FL_RETURN; if (kprobe_on_func_entry(NULL, symbol, offset)) flags |= TPARG_FL_FENTRY; - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { + if (!strchr(symbol, ':') && is_return && !(flags & TPARG_FL_FENTRY)) { trace_probe_log_err(0, BAD_RETPROBE); goto parse_error; } Thank you, > > Thank you! > > > > > -- Steve > > > > > > On Tue, 19 Jan 2021 23:10:14 +0800 > > Jianlin Lv <Jianlin.Lv@arm.com> wrote: > > > > > When trying to create kretprobe with the wrong function symbol in tracefs; > > > The error is triggered in the register_trace_kprobe() and recorded as > > > FAIL_REG_PROBE issue, > > > > > > Example: > > > $ cd /sys/kernel/debug/tracing > > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > > bash: echo: write error: Invalid argument > > > $ cat error_log > > > [142797.347877] trace_kprobe: error: Failed to register probe event > > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > > ^ > > > > > > This error can be detected in the parameter parsing stage, the effect of > > > applying this patch is as follows: > > > > > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > > bash: echo: write error: Invalid argument > > > $ cat error_log > > > [415.89]trace_kprobe: error: Retprobe address must be an function entry > > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > > ^ > > > > > > Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com> > > > --- > > > kernel/trace/trace_kprobe.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > > index e6fba1798771..3dfd1b6711a3 100644 > > > --- a/kernel/trace/trace_kprobe.c > > > +++ b/kernel/trace/trace_kprobe.c > > > @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) > > > flags |= TPARG_FL_RETURN; > > > if (kprobe_on_func_entry(NULL, symbol, offset)) > > > flags |= TPARG_FL_FENTRY; > > > - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { > > > + if (is_return && !(flags & TPARG_FL_FENTRY)) { > > > trace_probe_log_err(0, BAD_RETPROBE); > > > goto parse_error; > > > } > > > > > -- > Masami Hiramatsu <mhiramat@kernel.org> -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-20 4:20 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2021-01-19 15:10 [PATCH] tracing: precise log info for kretprobe addr err Jianlin Lv 2021-01-19 15:41 ` Steven Rostedt 2021-01-20 3:24 ` Masami Hiramatsu 2021-01-20 4:14 ` Masami Hiramatsu
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