aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/trace
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/kprobetrace.txt22
1 files changed, 11 insertions, 11 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 4208253b5a53..15415243a9a3 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -35,13 +35,13 @@ Synopsis of kprobe_events
35 MEMADDR : Address where the probe is inserted. 35 MEMADDR : Address where the probe is inserted.
36 36
37 FETCHARGS : Arguments. Each probe can have up to 128 args. 37 FETCHARGS : Arguments. Each probe can have up to 128 args.
38 %REG : Fetch register REG 38 %REG : Fetch register REG
39 @ADDR : Fetch memory at ADDR (ADDR should be in kernel) 39 @ADDR : Fetch memory at ADDR (ADDR should be in kernel)
40 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) 40 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
41 $sN : Fetch Nth entry of stack (N >= 0) 41 $stackN : Fetch Nth entry of stack (N >= 0)
42 $sa : Fetch stack address. 42 $stack : Fetch stack address.
43 $aN : Fetch function argument. (N >= 0)(*) 43 $argN : Fetch function argument. (N >= 0)(*)
44 $rv : Fetch return value.(**) 44 $retval : Fetch return value.(**)
45 +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) 45 +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***)
46 NAME=FETCHARG: Set NAME as the argument name of FETCHARG. 46 NAME=FETCHARG: Set NAME as the argument name of FETCHARG.
47 47
@@ -84,13 +84,13 @@ Usage examples
84To add a probe as a new event, write a new definition to kprobe_events 84To add a probe as a new event, write a new definition to kprobe_events
85as below. 85as below.
86 86
87 echo p:myprobe do_sys_open dfd=$a0 filename=$a1 flags=$a2 mode=$a3 > /sys/kernel/debug/tracing/kprobe_events 87 echo p:myprobe do_sys_open dfd=$arg0 filename=$arg1 flags=$arg2 mode=$arg3 > /sys/kernel/debug/tracing/kprobe_events
88 88
89 This sets a kprobe on the top of do_sys_open() function with recording 89 This sets a kprobe on the top of do_sys_open() function with recording
901st to 4th arguments as "myprobe" event. As this example shows, users can 901st to 4th arguments as "myprobe" event. As this example shows, users can
91choose more familiar names for each arguments. 91choose more familiar names for each arguments.
92 92
93 echo r:myretprobe do_sys_open $rv >> /sys/kernel/debug/tracing/kprobe_events 93 echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events
94 94
95 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
96recording return value as "myretprobe" event. 96recording return value as "myretprobe" event.
@@ -137,11 +137,11 @@ events, you need to enable it.
137# TASK-PID CPU# TIMESTAMP FUNCTION 137# TASK-PID CPU# TIMESTAMP FUNCTION
138# | | | | | 138# | | | | |
139 <...>-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
140 <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe 140 <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $retval=fffffffffffffffe
141 <...>-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
142 <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 142 <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3
143 <...>-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
144 <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 144 <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3
145 145
146 146
147 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