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 33f531858c56..4208253b5a53 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt | |||
@@ -1,4 +1,4 @@ | |||
1 | Kprobe-based Event Tracer | 1 | Kprobe-based Event Tracer |
2 | ========================= | 2 | ========================= |
3 | 3 | ||
4 | Documentation is written by Masami Hiramatsu | 4 | Documentation is written by Masami Hiramatsu |
@@ -42,7 +42,6 @@ Synopsis of kprobe_events | |||
42 | $sa : Fetch stack address. | 42 | $sa : Fetch stack address. |
43 | $aN : Fetch function argument. (N >= 0)(*) | 43 | $aN : Fetch function argument. (N >= 0)(*) |
44 | $rv : Fetch return value.(**) | 44 | $rv : Fetch return value.(**) |
45 | $ra : Fetch return address.(**) | ||
46 | +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) | 45 | +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) |
47 | NAME=FETCHARG: Set NAME as the argument name of FETCHARG. | 46 | NAME=FETCHARG: Set NAME as the argument name of FETCHARG. |
48 | 47 | ||
@@ -91,10 +90,10 @@ as below. | |||
91 | 1st to 4th arguments as "myprobe" event. As this example shows, users can | 90 | 1st to 4th arguments as "myprobe" event. As this example shows, users can |
92 | choose more familiar names for each arguments. | 91 | choose more familiar names for each arguments. |
93 | 92 | ||
94 | echo r:myretprobe do_sys_open $rv $ra >> /sys/kernel/debug/tracing/kprobe_events | 93 | echo r:myretprobe do_sys_open $rv >> /sys/kernel/debug/tracing/kprobe_events |
95 | 94 | ||
96 | This sets a kretprobe on the return point of do_sys_open() function with | 95 | This sets a kretprobe on the return point of do_sys_open() function with |
97 | recording return value and return address as "myretprobe" event. | 96 | recording return value as "myretprobe" event. |
98 | You can see the format of these events via | 97 | You can see the format of these events via |
99 | /sys/kernel/debug/tracing/events/kprobes/<EVENT>/format. | 98 | /sys/kernel/debug/tracing/events/kprobes/<EVENT>/format. |
100 | 99 | ||
@@ -138,11 +137,11 @@ events, you need to enable it. | |||
138 | # TASK-PID CPU# TIMESTAMP FUNCTION | 137 | # TASK-PID CPU# TIMESTAMP FUNCTION |
139 | # | | | | | | 138 | # | | | | | |
140 | <...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0 | 139 | <...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0 |
141 | <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe $ra=ffffffff81367a3a | 140 | <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe |
142 | <...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6 | 141 | <...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6 |
143 | <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a | 142 | <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 |
144 | <...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10 | 143 | <...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10 |
145 | <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a | 144 | <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 |
146 | 145 | ||
147 | 146 | ||
148 | Each line shows when the kernel hits an event, and <- SYMBOL means kernel | 147 | Each line shows when the kernel hits an event, and <- SYMBOL means kernel |