diff options
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 5 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 39 | ||||
| -rw-r--r-- | tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc | 39 |
3 files changed, 76 insertions, 7 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 41ef9d8efe95..25f39601a7f7 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -23,7 +23,7 @@ current_tracer. Instead of that, add probe points via Synopsis of kprobe_events ------------------------- p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS] : Set a probe - r[:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe + r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe -:[GRP/]EVENT : Clear a probe GRP : Group name. If omitted, use "kprobes" for it. @@ -32,6 +32,9 @@ Synopsis of kprobe_events MOD : Module name which has given SYM. SYM[+offs] : Symbol+offset where the probe is inserted. MEMADDR : Address where the probe is inserted. + MAXACTIVE : Maximum number of instances of the specified function that + can be probed simultaneously, or 0 for the default value + as defined in Documentation/kprobes.txt section 1.3.1. FETCHARGS : Arguments. Each probe can have up to 128 args. %REG : Fetch register REG diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 5f688cc724f0..f01d49b576c0 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -25,6 +25,7 @@ #include "trace_probe.h" #define KPROBE_EVENT_SYSTEM "kprobes" +#define KRETPROBE_MAXACTIVE_MAX 4096 /** * Kprobe event core functions @@ -282,6 +283,7 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group, void *addr, const char *symbol, unsigned long offs, + int maxactive, int nargs, bool is_return) { struct trace_kprobe *tk; @@ -309,6 +311,8 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group, else tk->rp.kp.pre_handler = kprobe_dispatcher; + tk->rp.maxactive = maxactive; + if (!event || !is_good_name(event)) { ret = -EINVAL; goto error; @@ -598,8 +602,10 @@ static int create_trace_kprobe(int argc, char **argv) { /* * Argument syntax: - * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] - * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] + * - Add kprobe: + * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] + * - Add kretprobe: + * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] * Fetch args: * $retval : fetch return value * $stack : fetch stack address @@ -619,6 +625,7 @@ static int create_trace_kprobe(int argc, char **argv) int i, ret = 0; bool is_return = false, is_delete = false; char *symbol = NULL, *event = NULL, *group = NULL; + int maxactive = 0; char *arg; unsigned long offset = 0; void *addr = NULL; @@ -637,8 +644,28 @@ static int create_trace_kprobe(int argc, char **argv) return -EINVAL; } - if (argv[0][1] == ':') { - event = &argv[0][2]; + event = strchr(&argv[0][1], ':'); + if (event) { + event[0] = '\0'; + event++; + } + if (is_return && isdigit(argv[0][1])) { + ret = kstrtouint(&argv[0][1], 0, &maxactive); + if (ret) { + pr_info("Failed to parse maxactive.\n"); + return ret; + } + /* kretprobes instances are iterated over via a list. The + * maximum should stay reasonable. + */ + if (maxactive > KRETPROBE_MAXACTIVE_MAX) { + pr_info("Maxactive is too big (%d > %d).\n", + maxactive, KRETPROBE_MAXACTIVE_MAX); + return -E2BIG; + } + } + + if (event) { if (strchr(event, '/')) { group = event; event = strchr(group, '/') + 1; @@ -718,8 +745,8 @@ static int create_trace_kprobe(int argc, char **argv) is_return ? 'r' : 'p', addr); event = buf; } - tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc, - is_return); + tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, + argc, is_return); if (IS_ERR(tk)) { pr_info("Failed to allocate trace_probe.(%d)\n", (int)PTR_ERR(tk)); diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc new file mode 100644 index 000000000000..57abdf1caabf --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc @@ -0,0 +1,39 @@ +#!/bin/sh +# description: Kretprobe dynamic event with maxactive + +[ -f kprobe_events ] || exit_unsupported # this is configurable + +echo > kprobe_events + +# Test if we successfully reject unknown messages +if echo 'a:myprobeaccept inet_csk_accept' > kprobe_events; then false; else true; fi + +# Test if we successfully reject too big maxactive +if echo 'r1000000:myprobeaccept inet_csk_accept' > kprobe_events; then false; else true; fi + +# Test if we successfully reject unparsable numbers for maxactive +if echo 'r10fuzz:myprobeaccept inet_csk_accept' > kprobe_events; then false; else true; fi + +# Test for kretprobe with event name without maxactive +echo 'r:myprobeaccept inet_csk_accept' > kprobe_events +grep myprobeaccept kprobe_events +test -d events/kprobes/myprobeaccept +echo '-:myprobeaccept' >> kprobe_events + +# Test for kretprobe with event name with a small maxactive +echo 'r10:myprobeaccept inet_csk_accept' > kprobe_events +grep myprobeaccept kprobe_events +test -d events/kprobes/myprobeaccept +echo '-:myprobeaccept' >> kprobe_events + +# Test for kretprobe without event name without maxactive +echo 'r inet_csk_accept' > kprobe_events +grep inet_csk_accept kprobe_events +echo > kprobe_events + +# Test for kretprobe without event name with a small maxactive +echo 'r10 inet_csk_accept' > kprobe_events +grep inet_csk_accept kprobe_events +echo > kprobe_events + +clear_trace |