diff options
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 13 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 11 |
2 files changed, 6 insertions, 18 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 33f531858c56..4208253b5a53 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -1,4 +1,4 @@ - Kprobe-based Event Tracer + Kprobe-based Event Tracer ========================= Documentation is written by Masami Hiramatsu @@ -42,7 +42,6 @@ Synopsis of kprobe_events $sa : Fetch stack address. $aN : Fetch function argument. (N >= 0)(*) $rv : Fetch return value.(**) - $ra : Fetch return address.(**) +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) NAME=FETCHARG: Set NAME as the argument name of FETCHARG. @@ -91,10 +90,10 @@ as below. 1st to 4th arguments as "myprobe" event. As this example shows, users can choose more familiar names for each arguments. - echo r:myretprobe do_sys_open $rv $ra >> /sys/kernel/debug/tracing/kprobe_events + echo r:myretprobe do_sys_open $rv >> /sys/kernel/debug/tracing/kprobe_events This sets a kretprobe on the return point of do_sys_open() function with -recording return value and return address as "myretprobe" event. +recording return value as "myretprobe" event. You can see the format of these events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/format. @@ -138,11 +137,11 @@ events, you need to enable it. # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0 - <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe $ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe <...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6 - <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 <...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10 - <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a + <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 Each line shows when the kernel hits an event, and <- SYMBOL means kernel diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index f63ead0cc5cf..ba6d3bd48889 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -85,11 +85,6 @@ static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs, return regs_return_value(regs); } -static __kprobes unsigned long fetch_ip(struct pt_regs *regs, void *dummy) -{ - return instruction_pointer(regs); -} - static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs, void *dummy) { @@ -234,8 +229,6 @@ static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff) ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset); } else if (ff->func == fetch_retvalue) ret = snprintf(buf, n, "$rv"); - else if (ff->func == fetch_ip) - ret = snprintf(buf, n, "$ra"); else if (ff->func == fetch_stack_address) ret = snprintf(buf, n, "$sa"); else if (ff->func == fetch_indirect) { @@ -448,9 +441,6 @@ static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return) if (is_return && arg[1] == 'v') { ff->func = fetch_retvalue; ff->data = NULL; - } else if (is_return && arg[1] == 'a') { - ff->func = fetch_ip; - ff->data = NULL; } else ret = -EINVAL; break; @@ -560,7 +550,6 @@ static int create_trace_probe(int argc, char **argv) * Fetch args: * $aN : fetch Nth of function argument. (N:0-) * $rv : fetch return value - * $ra : fetch return address * $sa : fetch stack address * $sN : fetch Nth of stack (N:0-) * @ADDR : fetch memory at ADDR (ADDR should be in kernel) |