tracing: Provide trace events interface for uprobes
Implements trace_event support for uprobes. In its current form
it can be used to put probes at a specified offset in a file and
dump the required registers when the code flow reaches the
probed address.
The following example shows how to dump the instruction pointer
and %ax a register at the probed text address. Here we are
trying to probe zfree in /bin/zsh:
# cd /sys/kernel/debug/tracing/
# cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
# objdump -T /bin/zsh | grep -w zfree
0000000000446420 g DF .text 0000000000000012 Base
zfree # echo 'p /bin/zsh:0x46420 %ip %ax' > uprobe_events
# cat uprobe_events
p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420
# echo 1 > events/uprobes/enable
# sleep 20
# echo 0 > events/uprobes/enable
# cat trace
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
zsh-24842 [006] 258544.995456: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
zsh-24842 [007] 258545.000270: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
zsh-24842 [002] 258545.043929: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
zsh-24842 [004] 258547.046129: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120411103043.GB29437@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Srikar Dronamraju
Ingo Molnar
parent
8ab83f5647
commit
f3f096cfed
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@ -0,0 +1,95 @@
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Uprobe-tracer: Uprobe-based Event Tracing
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=========================================
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Documentation written by Srikar Dronamraju
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Overview
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--------
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Uprobe based trace events are similar to kprobe based trace events.
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To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
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Similar to the kprobe-event tracer, this doesn't need to be activated via
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current_tracer. Instead of that, add probe points via
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/sys/kernel/debug/tracing/uprobe_events, and enable it via
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/sys/kernel/debug/tracing/events/uprobes/<EVENT>/enabled.
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However unlike kprobe-event tracer, the uprobe event interface expects the
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user to calculate the offset of the probepoint in the object
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Synopsis of uprobe_tracer
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-------------------------
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p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] : Set a probe
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GRP : Group name. If omitted, use "uprobes" for it.
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EVENT : Event name. If omitted, the event name is generated
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based on SYMBOL+offs.
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PATH : path to an executable or a library.
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SYMBOL[+offs] : Symbol+offset where the probe is inserted.
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FETCHARGS : Arguments. Each probe can have up to 128 args.
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%REG : Fetch register REG
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Event Profiling
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---------------
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You can check the total number of probe hits and probe miss-hits via
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/sys/kernel/debug/tracing/uprobe_profile.
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The first column is event name, the second is the number of probe hits,
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the third is the number of probe miss-hits.
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Usage examples
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--------------
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To add a probe as a new event, write a new definition to uprobe_events
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as below.
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echo 'p: /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
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This sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash
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echo > /sys/kernel/debug/tracing/uprobe_events
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This clears all probe points.
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The following example shows how to dump the instruction pointer and %ax
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a register at the probed text address. Here we are trying to probe
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function zfree in /bin/zsh
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# cd /sys/kernel/debug/tracing/
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# cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
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00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
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# objdump -T /bin/zsh | grep -w zfree
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0000000000446420 g DF .text 0000000000000012 Base zfree
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0x46420 is the offset of zfree in object /bin/zsh that is loaded at
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0x00400000. Hence the command to probe would be :
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# echo 'p /bin/zsh:0x46420 %ip %ax' > uprobe_events
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Please note: User has to explicitly calculate the offset of the probepoint
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in the object. We can see the events that are registered by looking at the
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uprobe_events file.
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# cat uprobe_events
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p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420
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Right after definition, each event is disabled by default. For tracing these
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events, you need to enable it by:
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# echo 1 > events/uprobes/enable
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Lets disable the event after sleeping for some time.
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# sleep 20
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# echo 0 > events/uprobes/enable
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And you can see the traced information via /sys/kernel/debug/tracing/trace.
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# cat trace
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# tracer: nop
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#
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# TASK-PID CPU# TIMESTAMP FUNCTION
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# | | | | |
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zsh-24842 [006] 258544.995456: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
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zsh-24842 [007] 258545.000270: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
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zsh-24842 [002] 258545.043929: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
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zsh-24842 [004] 258547.046129: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79
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Each line shows us probes were triggered for a pid 24842 with ip being
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0x446421 and contents of ax register being 79.
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@ -78,7 +78,7 @@ config OPTPROBES
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config UPROBES
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bool "Transparent user-space probes (EXPERIMENTAL)"
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depends on ARCH_SUPPORTS_UPROBES && PERF_EVENTS
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depends on UPROBE_EVENTS && PERF_EVENTS
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default n
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help
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Uprobes is the user-space counterpart to kprobes: they
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@ -386,6 +386,22 @@ config KPROBE_EVENT
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This option is also required by perf-probe subcommand of perf tools.
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If you want to use perf tools, this option is strongly recommended.
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config UPROBE_EVENT
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bool "Enable uprobes-based dynamic events"
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depends on ARCH_SUPPORTS_UPROBES
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depends on MMU
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select UPROBES
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select PROBE_EVENTS
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select TRACING
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default n
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help
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This allows the user to add tracing events on top of userspace
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dynamic events (similar to tracepoints) on the fly via the trace
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events interface. Those events can be inserted wherever uprobes
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can probe, and record various registers.
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This option is required if you plan to use perf-probe subcommand
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of perf tools on user space applications.
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config PROBE_EVENTS
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def_bool n
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@ -62,5 +62,6 @@ ifeq ($(CONFIG_TRACING),y)
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obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
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endif
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obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
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obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o
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libftrace-y := ftrace.o
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@ -103,6 +103,11 @@ struct kretprobe_trace_entry_head {
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unsigned long ret_ip;
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};
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struct uprobe_trace_entry_head {
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struct trace_entry ent;
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unsigned long ip;
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};
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/*
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* trace_flag_type is an enumeration that holds different
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* states when a trace occurs. These are:
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@ -525,7 +525,7 @@ static int create_trace_probe(int argc, char **argv)
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/* Parse fetch argument */
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ret = traceprobe_parse_probe_arg(arg, &tp->size, &tp->args[i],
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is_return);
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is_return, true);
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if (ret) {
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pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
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goto error;
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@ -550,7 +550,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
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/* Recursive argument parser */
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static int parse_probe_arg(char *arg, const struct fetch_type *t,
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struct fetch_param *f, bool is_return)
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struct fetch_param *f, bool is_return, bool is_kprobe)
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{
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unsigned long param;
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long offset;
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@ -558,6 +558,11 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
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int ret;
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ret = 0;
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/* Until uprobe_events supports only reg arguments */
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if (!is_kprobe && arg[0] != '%')
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return -EINVAL;
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switch (arg[0]) {
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case '$':
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ret = parse_probe_vars(arg + 1, t, f, is_return);
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@ -619,7 +624,8 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
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return -ENOMEM;
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dprm->offset = offset;
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ret = parse_probe_arg(arg, t2, &dprm->orig, is_return);
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ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
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is_kprobe);
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if (ret)
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kfree(dprm);
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else {
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@ -677,7 +683,7 @@ static int __parse_bitfield_probe_arg(const char *bf,
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/* String length checking wrapper */
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int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
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struct probe_arg *parg, bool is_return)
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struct probe_arg *parg, bool is_return, bool is_kprobe)
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{
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const char *t;
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int ret;
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@ -703,7 +709,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
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}
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parg->offset = *size;
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*size += parg->type->size;
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ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
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ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
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if (ret >= 0 && t != NULL)
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ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
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@ -66,6 +66,7 @@
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#define TP_FLAG_TRACE 1
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#define TP_FLAG_PROFILE 2
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#define TP_FLAG_REGISTERED 4
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#define TP_FLAG_UPROBE 8
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/* data_rloc: data relative location, compatible with u32 */
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@ -143,7 +144,7 @@ static inline int is_good_name(const char *name)
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}
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extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
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struct probe_arg *parg, bool is_return);
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struct probe_arg *parg, bool is_return, bool is_kprobe);
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extern int traceprobe_conflict_field_name(const char *name,
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struct probe_arg *args, int narg);
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@ -0,0 +1,788 @@
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/*
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* uprobes-based tracing events
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Copyright (C) IBM Corporation, 2010-2012
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* Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <linux/uprobes.h>
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#include <linux/namei.h>
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#include "trace_probe.h"
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#define UPROBE_EVENT_SYSTEM "uprobes"
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/*
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* uprobe event core functions
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*/
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struct trace_uprobe;
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struct uprobe_trace_consumer {
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struct uprobe_consumer cons;
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struct trace_uprobe *tu;
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};
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struct trace_uprobe {
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struct list_head list;
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struct ftrace_event_class class;
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struct ftrace_event_call call;
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struct uprobe_trace_consumer *consumer;
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struct inode *inode;
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char *filename;
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unsigned long offset;
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unsigned long nhit;
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unsigned int flags; /* For TP_FLAG_* */
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ssize_t size; /* trace entry size */
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unsigned int nr_args;
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struct probe_arg args[];
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};
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#define SIZEOF_TRACE_UPROBE(n) \
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(offsetof(struct trace_uprobe, args) + \
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(sizeof(struct probe_arg) * (n)))
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static int register_uprobe_event(struct trace_uprobe *tu);
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static void unregister_uprobe_event(struct trace_uprobe *tu);
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static DEFINE_MUTEX(uprobe_lock);
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static LIST_HEAD(uprobe_list);
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static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
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/*
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* Allocate new trace_uprobe and initialize it (including uprobes).
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*/
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static struct trace_uprobe *
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alloc_trace_uprobe(const char *group, const char *event, int nargs)
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{
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struct trace_uprobe *tu;
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if (!event || !is_good_name(event))
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return ERR_PTR(-EINVAL);
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if (!group || !is_good_name(group))
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return ERR_PTR(-EINVAL);
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tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
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if (!tu)
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return ERR_PTR(-ENOMEM);
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tu->call.class = &tu->class;
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tu->call.name = kstrdup(event, GFP_KERNEL);
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if (!tu->call.name)
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goto error;
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tu->class.system = kstrdup(group, GFP_KERNEL);
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if (!tu->class.system)
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goto error;
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INIT_LIST_HEAD(&tu->list);
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return tu;
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error:
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kfree(tu->call.name);
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kfree(tu);
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return ERR_PTR(-ENOMEM);
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}
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static void free_trace_uprobe(struct trace_uprobe *tu)
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{
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int i;
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for (i = 0; i < tu->nr_args; i++)
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traceprobe_free_probe_arg(&tu->args[i]);
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iput(tu->inode);
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kfree(tu->call.class->system);
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kfree(tu->call.name);
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kfree(tu->filename);
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kfree(tu);
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}
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static struct trace_uprobe *find_probe_event(const char *event, const char *group)
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{
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struct trace_uprobe *tu;
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list_for_each_entry(tu, &uprobe_list, list)
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if (strcmp(tu->call.name, event) == 0 &&
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strcmp(tu->call.class->system, group) == 0)
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return tu;
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return NULL;
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}
|
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|
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/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
|
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static void unregister_trace_uprobe(struct trace_uprobe *tu)
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{
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list_del(&tu->list);
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unregister_uprobe_event(tu);
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free_trace_uprobe(tu);
|
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}
|
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|
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/* Register a trace_uprobe and probe_event */
|
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static int register_trace_uprobe(struct trace_uprobe *tu)
|
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{
|
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struct trace_uprobe *old_tp;
|
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int ret;
|
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|
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mutex_lock(&uprobe_lock);
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|
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/* register as an event */
|
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old_tp = find_probe_event(tu->call.name, tu->call.class->system);
|
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if (old_tp)
|
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/* delete old event */
|
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unregister_trace_uprobe(old_tp);
|
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|
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ret = register_uprobe_event(tu);
|
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if (ret) {
|
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pr_warning("Failed to register probe event(%d)\n", ret);
|
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goto end;
|
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}
|
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|
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list_add_tail(&tu->list, &uprobe_list);
|
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|
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end:
|
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mutex_unlock(&uprobe_lock);
|
||||
|
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return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* Argument syntax:
|
||||
* - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS]
|
||||
*
|
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* - Remove uprobe: -:[GRP/]EVENT
|
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*/
|
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static int create_trace_uprobe(int argc, char **argv)
|
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{
|
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struct trace_uprobe *tu;
|
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struct inode *inode;
|
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char *arg, *event, *group, *filename;
|
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char buf[MAX_EVENT_NAME_LEN];
|
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struct path path;
|
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unsigned long offset;
|
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bool is_delete;
|
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int i, ret;
|
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|
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inode = NULL;
|
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ret = 0;
|
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is_delete = false;
|
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event = NULL;
|
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group = NULL;
|
||||
|
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/* argc must be >= 1 */
|
||||
if (argv[0][0] == '-')
|
||||
is_delete = true;
|
||||
else if (argv[0][0] != 'p') {
|
||||
pr_info("Probe definition must be started with 'p', 'r' or" " '-'.\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
if (argv[0][1] == ':') {
|
||||
event = &argv[0][2];
|
||||
arg = strchr(event, '/');
|
||||
|
||||
if (arg) {
|
||||
group = event;
|
||||
event = arg + 1;
|
||||
event[-1] = '\0';
|
||||
|
||||
if (strlen(group) == 0) {
|
||||
pr_info("Group name is not specified\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
if (strlen(event) == 0) {
|
||||
pr_info("Event name is not specified\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
if (!group)
|
||||
group = UPROBE_EVENT_SYSTEM;
|
||||
|
||||
if (is_delete) {
|
||||
if (!event) {
|
||||
pr_info("Delete command needs an event name.\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
mutex_lock(&uprobe_lock);
|
||||
tu = find_probe_event(event, group);
|
||||
|
||||
if (!tu) {
|
||||
mutex_unlock(&uprobe_lock);
|
||||
pr_info("Event %s/%s doesn't exist.\n", group, event);
|
||||
return -ENOENT;
|
||||
}
|
||||
/* delete an event */
|
||||
unregister_trace_uprobe(tu);
|
||||
mutex_unlock(&uprobe_lock);
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (argc < 2) {
|
||||
pr_info("Probe point is not specified.\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
if (isdigit(argv[1][0])) {
|
||||
pr_info("probe point must be have a filename.\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
arg = strchr(argv[1], ':');
|
||||
if (!arg)
|
||||
goto fail_address_parse;
|
||||
|
||||
*arg++ = '\0';
|
||||
filename = argv[1];
|
||||
ret = kern_path(filename, LOOKUP_FOLLOW, &path);
|
||||
if (ret)
|
||||
goto fail_address_parse;
|
||||
|
||||
ret = strict_strtoul(arg, 0, &offset);
|
||||
if (ret)
|
||||
goto fail_address_parse;
|
||||
|
||||
inode = igrab(path.dentry->d_inode);
|
||||
|
||||
argc -= 2;
|
||||
argv += 2;
|
||||
|
||||
/* setup a probe */
|
||||
if (!event) {
|
||||
char *tail = strrchr(filename, '/');
|
||||
char *ptr;
|
||||
|
||||
ptr = kstrdup((tail ? tail + 1 : filename), GFP_KERNEL);
|
||||
if (!ptr) {
|
||||
ret = -ENOMEM;
|
||||
goto fail_address_parse;
|
||||
}
|
||||
|
||||
tail = ptr;
|
||||
ptr = strpbrk(tail, ".-_");
|
||||
if (ptr)
|
||||
*ptr = '\0';
|
||||
|
||||
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
|
||||
event = buf;
|
||||
kfree(tail);
|
||||
}
|
||||
|
||||
tu = alloc_trace_uprobe(group, event, argc);
|
||||
if (IS_ERR(tu)) {
|
||||
pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
|
||||
ret = PTR_ERR(tu);
|
||||
goto fail_address_parse;
|
||||
}
|
||||
tu->offset = offset;
|
||||
tu->inode = inode;
|
||||
tu->filename = kstrdup(filename, GFP_KERNEL);
|
||||
|
||||
if (!tu->filename) {
|
||||
pr_info("Failed to allocate filename.\n");
|
||||
ret = -ENOMEM;
|
||||
goto error;
|
||||
}
|
||||
|
||||
/* parse arguments */
|
||||
ret = 0;
|
||||
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
|
||||
/* Increment count for freeing args in error case */
|
||||
tu->nr_args++;
|
||||
|
||||
/* Parse argument name */
|
||||
arg = strchr(argv[i], '=');
|
||||
if (arg) {
|
||||
*arg++ = '\0';
|
||||
tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
|
||||
} else {
|
||||
arg = argv[i];
|
||||
/* If argument name is omitted, set "argN" */
|
||||
snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
|
||||
tu->args[i].name = kstrdup(buf, GFP_KERNEL);
|
||||
}
|
||||
|
||||
if (!tu->args[i].name) {
|
||||
pr_info("Failed to allocate argument[%d] name.\n", i);
|
||||
ret = -ENOMEM;
|
||||
goto error;
|
||||
}
|
||||
|
||||
if (!is_good_name(tu->args[i].name)) {
|
||||
pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
|
||||
ret = -EINVAL;
|
||||
goto error;
|
||||
}
|
||||
|
||||
if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
|
||||
pr_info("Argument[%d] name '%s' conflicts with "
|
||||
"another field.\n", i, argv[i]);
|
||||
ret = -EINVAL;
|
||||
goto error;
|
||||
}
|
||||
|
||||
/* Parse fetch argument */
|
||||
ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
|
||||
if (ret) {
|
||||
pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
|
||||
ret = register_trace_uprobe(tu);
|
||||
if (ret)
|
||||
goto error;
|
||||
return 0;
|
||||
|
||||
error:
|
||||
free_trace_uprobe(tu);
|
||||
return ret;
|
||||
|
||||
fail_address_parse:
|
||||
if (inode)
|
||||
iput(inode);
|
||||
|
||||
pr_info("Failed to parse address.\n");
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void cleanup_all_probes(void)
|
||||
{
|
||||
struct trace_uprobe *tu;
|
||||
|
||||
mutex_lock(&uprobe_lock);
|
||||
while (!list_empty(&uprobe_list)) {
|
||||
tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
|
||||
unregister_trace_uprobe(tu);
|
||||
}
|
||||
mutex_unlock(&uprobe_lock);
|
||||
}
|
||||
|
||||
/* Probes listing interfaces */
|
||||
static void *probes_seq_start(struct seq_file *m, loff_t *pos)
|
||||
{
|
||||
mutex_lock(&uprobe_lock);
|
||||
return seq_list_start(&uprobe_list, *pos);
|
||||
}
|
||||
|
||||
static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
|
||||
{
|
||||
return seq_list_next(v, &uprobe_list, pos);
|
||||
}
|
||||
|
||||
static void probes_seq_stop(struct seq_file *m, void *v)
|
||||
{
|
||||
mutex_unlock(&uprobe_lock);
|
||||
}
|
||||
|
||||
static int probes_seq_show(struct seq_file *m, void *v)
|
||||
{
|
||||
struct trace_uprobe *tu = v;
|
||||
int i;
|
||||
|
||||
seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name);
|
||||
seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
|
||||
|
||||
for (i = 0; i < tu->nr_args; i++)
|
||||
seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
|
||||
|
||||
seq_printf(m, "\n");
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct seq_operations probes_seq_op = {
|
||||
.start = probes_seq_start,
|
||||
.next = probes_seq_next,
|
||||
.stop = probes_seq_stop,
|
||||
.show = probes_seq_show
|
||||
};
|
||||
|
||||
static int probes_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
|
||||
cleanup_all_probes();
|
||||
|
||||
return seq_open(file, &probes_seq_op);
|
||||
}
|
||||
|
||||
static ssize_t probes_write(struct file *file, const char __user *buffer,
|
||||
size_t count, loff_t *ppos)
|
||||
{
|
||||
return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
|
||||
}
|
||||
|
||||
static const struct file_operations uprobe_events_ops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = probes_open,
|
||||
.read = seq_read,
|
||||
.llseek = seq_lseek,
|
||||
.release = seq_release,
|
||||
.write = probes_write,
|
||||
};
|
||||
|
||||
/* Probes profiling interfaces */
|
||||
static int probes_profile_seq_show(struct seq_file *m, void *v)
|
||||
{
|
||||
struct trace_uprobe *tu = v;
|
||||
|
||||
seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct seq_operations profile_seq_op = {
|
||||
.start = probes_seq_start,
|
||||
.next = probes_seq_next,
|
||||
.stop = probes_seq_stop,
|
||||
.show = probes_profile_seq_show
|
||||
};
|
||||
|
||||
static int profile_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
return seq_open(file, &profile_seq_op);
|
||||
}
|
||||
|
||||
static const struct file_operations uprobe_profile_ops = {
|
||||
.owner = THIS_MODULE,
|
||||
.open = profile_open,
|
||||
.read = seq_read,
|
||||
.llseek = seq_lseek,
|
||||
.release = seq_release,
|
||||
};
|
||||
|
||||
/* uprobe handler */
|
||||
static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
|
||||
{
|
||||
struct uprobe_trace_entry_head *entry;
|
||||
struct ring_buffer_event *event;
|
||||
struct ring_buffer *buffer;
|
||||
u8 *data;
|
||||
int size, i, pc;
|
||||
unsigned long irq_flags;
|
||||
struct ftrace_event_call *call = &tu->call;
|
||||
|
||||
tu->nhit++;
|
||||
|
||||
local_save_flags(irq_flags);
|
||||
pc = preempt_count();
|
||||
|
||||
size = sizeof(*entry) + tu->size;
|
||||
|
||||
event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
|
||||
size, irq_flags, pc);
|
||||
if (!event)
|
||||
return;
|
||||
|
||||
entry = ring_buffer_event_data(event);
|
||||
entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
|
||||
data = (u8 *)&entry[1];
|
||||
for (i = 0; i < tu->nr_args; i++)
|
||||
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
|
||||
|
||||
if (!filter_current_check_discard(buffer, call, entry, event))
|
||||
trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
|
||||
}
|
||||
|
||||
/* Event entry printers */
|
||||
static enum print_line_t
|
||||
print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
|
||||
{
|
||||
struct uprobe_trace_entry_head *field;
|
||||
struct trace_seq *s = &iter->seq;
|
||||
struct trace_uprobe *tu;
|
||||
u8 *data;
|
||||
int i;
|
||||
|
||||
field = (struct uprobe_trace_entry_head *)iter->ent;
|
||||
tu = container_of(event, struct trace_uprobe, call.event);
|
||||
|
||||
if (!trace_seq_printf(s, "%s: (", tu->call.name))
|
||||
goto partial;
|
||||
|
||||
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
|
||||
goto partial;
|
||||
|
||||
if (!trace_seq_puts(s, ")"))
|
||||
goto partial;
|
||||
|
||||
data = (u8 *)&field[1];
|
||||
for (i = 0; i < tu->nr_args; i++) {
|
||||
if (!tu->args[i].type->print(s, tu->args[i].name,
|
||||
data + tu->args[i].offset, field))
|
||||
goto partial;
|
||||
}
|
||||
|
||||
if (trace_seq_puts(s, "\n"))
|
||||
return TRACE_TYPE_HANDLED;
|
||||
|
||||
partial:
|
||||
return TRACE_TYPE_PARTIAL_LINE;
|
||||
}
|
||||
|
||||
static int probe_event_enable(struct trace_uprobe *tu, int flag)
|
||||
{
|
||||
struct uprobe_trace_consumer *utc;
|
||||
int ret = 0;
|
||||
|
||||
if (!tu->inode || tu->consumer)
|
||||
return -EINTR;
|
||||
|
||||
utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
|
||||
if (!utc)
|
||||
return -EINTR;
|
||||
|
||||
utc->cons.handler = uprobe_dispatcher;
|
||||
utc->cons.filter = NULL;
|
||||
ret = uprobe_register(tu->inode, tu->offset, &utc->cons);
|
||||
if (ret) {
|
||||
kfree(utc);
|
||||
return ret;
|
||||
}
|
||||
|
||||
tu->flags |= flag;
|
||||
utc->tu = tu;
|
||||
tu->consumer = utc;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void probe_event_disable(struct trace_uprobe *tu, int flag)
|
||||
{
|
||||
if (!tu->inode || !tu->consumer)
|
||||
return;
|
||||
|
||||
uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
|
||||
tu->flags &= ~flag;
|
||||
kfree(tu->consumer);
|
||||
tu->consumer = NULL;
|
||||
}
|
||||
|
||||
static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
|
||||
{
|
||||
int ret, i;
|
||||
struct uprobe_trace_entry_head field;
|
||||
struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
|
||||
|
||||
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
|
||||
/* Set argument names as fields */
|
||||
for (i = 0; i < tu->nr_args; i++) {
|
||||
ret = trace_define_field(event_call, tu->args[i].type->fmttype,
|
||||
tu->args[i].name,
|
||||
sizeof(field) + tu->args[i].offset,
|
||||
tu->args[i].type->size,
|
||||
tu->args[i].type->is_signed,
|
||||
FILTER_OTHER);
|
||||
|
||||
if (ret)
|
||||
return ret;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define LEN_OR_ZERO (len ? len - pos : 0)
|
||||
static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
|
||||
{
|
||||
const char *fmt, *arg;
|
||||
int i;
|
||||
int pos = 0;
|
||||
|
||||
fmt = "(%lx)";
|
||||
arg = "REC->" FIELD_STRING_IP;
|
||||
|
||||
/* When len=0, we just calculate the needed length */
|
||||
|
||||
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
|
||||
|
||||
for (i = 0; i < tu->nr_args; i++) {
|
||||
pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
|
||||
tu->args[i].name, tu->args[i].type->fmt);
|
||||
}
|
||||
|
||||
pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
|
||||
|
||||
for (i = 0; i < tu->nr_args; i++) {
|
||||
pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
|
||||
tu->args[i].name);
|
||||
}
|
||||
|
||||
return pos; /* return the length of print_fmt */
|
||||
}
|
||||
#undef LEN_OR_ZERO
|
||||
|
||||
static int set_print_fmt(struct trace_uprobe *tu)
|
||||
{
|
||||
char *print_fmt;
|
||||
int len;
|
||||
|
||||
/* First: called with 0 length to calculate the needed length */
|
||||
len = __set_print_fmt(tu, NULL, 0);
|
||||
print_fmt = kmalloc(len + 1, GFP_KERNEL);
|
||||
if (!print_fmt)
|
||||
return -ENOMEM;
|
||||
|
||||
/* Second: actually write the @print_fmt */
|
||||
__set_print_fmt(tu, print_fmt, len + 1);
|
||||
tu->call.print_fmt = print_fmt;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_PERF_EVENTS
|
||||
/* uprobe profile handler */
|
||||
static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
|
||||
{
|
||||
struct ftrace_event_call *call = &tu->call;
|
||||
struct uprobe_trace_entry_head *entry;
|
||||
struct hlist_head *head;
|
||||
u8 *data;
|
||||
int size, __size, i;
|
||||
int rctx;
|
||||
|
||||
__size = sizeof(*entry) + tu->size;
|
||||
size = ALIGN(__size + sizeof(u32), sizeof(u64));
|
||||
size -= sizeof(u32);
|
||||
if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
|
||||
return;
|
||||
|
||||
preempt_disable();
|
||||
|
||||
entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
|
||||
if (!entry)
|
||||
goto out;
|
||||
|
||||
entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
|
||||
data = (u8 *)&entry[1];
|
||||
for (i = 0; i < tu->nr_args; i++)
|
||||
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
|
||||
|
||||
head = this_cpu_ptr(call->perf_events);
|
||||
perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
|
||||
|
||||
out:
|
||||
preempt_enable();
|
||||
}
|
||||
#endif /* CONFIG_PERF_EVENTS */
|
||||
|
||||
static
|
||||
int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
|
||||
{
|
||||
struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
|
||||
|
||||
switch (type) {
|
||||
case TRACE_REG_REGISTER:
|
||||
return probe_event_enable(tu, TP_FLAG_TRACE);
|
||||
|
||||
case TRACE_REG_UNREGISTER:
|
||||
probe_event_disable(tu, TP_FLAG_TRACE);
|
||||
return 0;
|
||||
|
||||
#ifdef CONFIG_PERF_EVENTS
|
||||
case TRACE_REG_PERF_REGISTER:
|
||||
return probe_event_enable(tu, TP_FLAG_PROFILE);
|
||||
|
||||
case TRACE_REG_PERF_UNREGISTER:
|
||||
probe_event_disable(tu, TP_FLAG_PROFILE);
|
||||
return 0;
|
||||
#endif
|
||||
default:
|
||||
return 0;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
|
||||
{
|
||||
struct uprobe_trace_consumer *utc;
|
||||
struct trace_uprobe *tu;
|
||||
|
||||
utc = container_of(con, struct uprobe_trace_consumer, cons);
|
||||
tu = utc->tu;
|
||||
if (!tu || tu->consumer != utc)
|
||||
return 0;
|
||||
|
||||
if (tu->flags & TP_FLAG_TRACE)
|
||||
uprobe_trace_func(tu, regs);
|
||||
|
||||
#ifdef CONFIG_PERF_EVENTS
|
||||
if (tu->flags & TP_FLAG_PROFILE)
|
||||
uprobe_perf_func(tu, regs);
|
||||
#endif
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct trace_event_functions uprobe_funcs = {
|
||||
.trace = print_uprobe_event
|
||||
};
|
||||
|
||||
static int register_uprobe_event(struct trace_uprobe *tu)
|
||||
{
|
||||
struct ftrace_event_call *call = &tu->call;
|
||||
int ret;
|
||||
|
||||
/* Initialize ftrace_event_call */
|
||||
INIT_LIST_HEAD(&call->class->fields);
|
||||
call->event.funcs = &uprobe_funcs;
|
||||
call->class->define_fields = uprobe_event_define_fields;
|
||||
|
||||
if (set_print_fmt(tu) < 0)
|
||||
return -ENOMEM;
|
||||
|
||||
ret = register_ftrace_event(&call->event);
|
||||
if (!ret) {
|
||||
kfree(call->print_fmt);
|
||||
return -ENODEV;
|
||||
}
|
||||
call->flags = 0;
|
||||
call->class->reg = trace_uprobe_register;
|
||||
call->data = tu;
|
||||
ret = trace_add_event_call(call);
|
||||
|
||||
if (ret) {
|
||||
pr_info("Failed to register uprobe event: %s\n", call->name);
|
||||
kfree(call->print_fmt);
|
||||
unregister_ftrace_event(&call->event);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void unregister_uprobe_event(struct trace_uprobe *tu)
|
||||
{
|
||||
/* tu->event is unregistered in trace_remove_event_call() */
|
||||
trace_remove_event_call(&tu->call);
|
||||
kfree(tu->call.print_fmt);
|
||||
tu->call.print_fmt = NULL;
|
||||
}
|
||||
|
||||
/* Make a trace interface for controling probe points */
|
||||
static __init int init_uprobe_trace(void)
|
||||
{
|
||||
struct dentry *d_tracer;
|
||||
|
||||
d_tracer = tracing_init_dentry();
|
||||
if (!d_tracer)
|
||||
return 0;
|
||||
|
||||
trace_create_file("uprobe_events", 0644, d_tracer,
|
||||
NULL, &uprobe_events_ops);
|
||||
/* Profile interface */
|
||||
trace_create_file("uprobe_profile", 0444, d_tracer,
|
||||
NULL, &uprobe_profile_ops);
|
||||
return 0;
|
||||
}
|
||||
|
||||
fs_initcall(init_uprobe_trace);
|
||||
Reference in New Issue