Lines Matching +full:enable +full:- +full:offset
2 Uprobe-tracer: Uprobe-based Event Tracing
9 --------
11 To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
13 Similar to the kprobe-event tracer, this doesn't need to be activated via
15 /sys/kernel/tracing/uprobe_events, and enable it via
16 /sys/kernel/tracing/events/uprobes/<EVENT>/enable.
18 However unlike kprobe-event tracer, the uprobe event interface expects the
19 user to calculate the offset of the probepoint in the object.
26 -------------------------
29 p[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a uprobe
30 r[:[GRP/][EVENT]] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
31 p[:[GRP/][EVENT]] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
32 -:[GRP/][EVENT] : Clear uprobe or uretprobe event
36 on PATH+OFFSET.
38 OFFSET : Offset where the probe is inserted.
39 OFFSET%return : Offset where the return probe is inserted.
44 @+OFFSET : Fetch memory at OFFSET (OFFSET from same file as PATH)
49 +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3)
59 events can access only user-space memory.
62 -----
63 Several types are supported for fetch-args. Uprobe tracer will access memory
67 or 'x64' is used depends on the architecture (e.g. x86-32 uses x32, and
68 x86-64 uses x64).
69 String type is a special type, which fetches a "null-terminated" string from
71 Bitfield is another special type, which takes 3 parameters, bit-width, bit-
72 offset, and container-size (usually 32). The syntax is::
74 b<bit-width>@<bit-offset>/<container-size>
80 ---------------
86 --------------
88 as below (sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash)::
98 echo '-:p_bash_0x4245c0' >> /sys/kernel/tracing/uprobe_events
112 # cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
113 00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
114 # objdump -T /bin/zsh | grep -w zfree
117 0x46420 is the offset of zfree in object /bin/zsh that is loaded at
126 .. note:: User has to explicitly calculate the offset of the probe-point
143 field:unsigned short common_type; offset:0; size:2; signed:0;
144 field:unsigned char common_flags; offset:2; size:1; signed:0;
145 field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
146 field:int common_pid; offset:4; size:4; signed:1;
147 field:int common_padding; offset:8; size:4; signed:1;
149 field:unsigned long __probe_ip; offset:12; size:4; signed:0;
150 field:u32 arg1; offset:16; size:4; signed:0;
151 field:u32 arg2; offset:20; size:4; signed:0;
153 print fmt: "(%lx) arg1=%lx arg2=%lx", REC->__probe_ip, REC->arg1, REC->arg2
156 events, you need to enable it by::
158 # echo 1 > events/uprobes/enable
169 # echo 0 > events/uprobes/enable
177 # TASK-PID CPU# TIMESTAMP FUNCTION
179 zsh-24842 [006] 258544.995456: zfree_entry: (0x446420) arg1=446420 arg2=79
180 … zsh-24842 [007] 258545.000270: zfree_exit: (0x446540 <- 0x446420) arg1=446540 arg2=0
181 zsh-24842 [002] 258545.043929: zfree_entry: (0x446420) arg1=446420 arg2=79
182 … zsh-24842 [004] 258547.046129: zfree_exit: (0x446540 <- 0x446420) arg1=446540 arg2=0