diff options
Diffstat (limited to 'Documentation/trace/kprobetrace.txt')
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 33f531858c5..4208253b5a5 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 |