diff options
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 22 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 52 |
2 files changed, 35 insertions, 39 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 MEMADDR : Address where the probe is inserted. FETCHARGS : Arguments. Each probe can have up to 128 args. - %REG : Fetch register REG - @ADDR : Fetch memory at ADDR (ADDR should be in kernel) + %REG : Fetch register REG + @ADDR : Fetch memory at ADDR (ADDR should be in kernel) @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) - $sN : Fetch Nth entry of stack (N >= 0) - $sa : Fetch stack address. - $aN : Fetch function argument. (N >= 0)(*) - $rv : Fetch return value.(**) + $stackN : Fetch Nth entry of stack (N >= 0) + $stack : Fetch stack address. + $argN : Fetch function argument. (N >= 0)(*) + $retval : Fetch return value.(**) +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) NAME=FETCHARG: Set NAME as the argument name of FETCHARG. @@ -84,13 +84,13 @@ Usage examples To add a probe as a new event, write a new definition to kprobe_events as below. - echo p:myprobe do_sys_open dfd=$a0 filename=$a1 flags=$a2 mode=$a3 > /sys/kernel/debug/tracing/kprobe_events + echo p:myprobe do_sys_open dfd=$arg0 filename=$arg1 flags=$arg2 mode=$arg3 > /sys/kernel/debug/tracing/kprobe_events This sets a kprobe on the top of do_sys_open() function with recording 1st to 4th arguments as "myprobe" event. As this example shows, users can choose more familiar names for each arguments. - echo r:myretprobe do_sys_open $rv >> /sys/kernel/debug/tracing/kprobe_events + echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events This sets a kretprobe on the return point of do_sys_open() function with recording return value as "myretprobe" event. @@ -137,11 +137,11 @@ events, you need to enable it. # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0 - <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe + <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $retval=fffffffffffffffe <...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6 - <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 + <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3 <...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10 - <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 + <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3 Each line shows when the kernel hits an event, and <- SYMBOL means kernel diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index ba6d3bd48889..3313fa74ce5f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -215,22 +215,22 @@ static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff) int ret = -EINVAL; if (ff->func == fetch_argument) - ret = snprintf(buf, n, "$a%lu", (unsigned long)ff->data); + ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data); else if (ff->func == fetch_register) { const char *name; name = regs_query_register_name((unsigned int)((long)ff->data)); ret = snprintf(buf, n, "%%%s", name); } else if (ff->func == fetch_stack) - ret = snprintf(buf, n, "$s%lu", (unsigned long)ff->data); + ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data); else if (ff->func == fetch_memory) ret = snprintf(buf, n, "@0x%p", ff->data); else if (ff->func == fetch_symbol) { struct symbol_cache *sc = ff->data; ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset); } else if (ff->func == fetch_retvalue) - ret = snprintf(buf, n, "$rv"); + ret = snprintf(buf, n, "$retval"); else if (ff->func == fetch_stack_address) - ret = snprintf(buf, n, "$sa"); + ret = snprintf(buf, n, "$stack"); else if (ff->func == fetch_indirect) { struct indirect_fetch_data *id = ff->data; size_t l = 0; @@ -427,40 +427,36 @@ static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return) int ret = 0; unsigned long param; - switch (arg[0]) { - case 'a': /* argument */ - ret = strict_strtoul(arg + 1, 10, ¶m); - if (ret || param > PARAM_MAX_ARGS) - ret = -EINVAL; - else { - ff->func = fetch_argument; - ff->data = (void *)param; - } - break; - case 'r': /* retval or retaddr */ - if (is_return && arg[1] == 'v') { + if (strcmp(arg, "retval") == 0) { + if (is_return) { ff->func = fetch_retvalue; ff->data = NULL; } else ret = -EINVAL; - break; - case 's': /* stack */ - if (arg[1] == 'a') { + } else if (strncmp(arg, "stack", 5) == 0) { + if (arg[5] == '\0') { ff->func = fetch_stack_address; ff->data = NULL; - } else { - ret = strict_strtoul(arg + 1, 10, ¶m); + } else if (isdigit(arg[5])) { + ret = strict_strtoul(arg + 5, 10, ¶m); if (ret || param > PARAM_MAX_STACK) ret = -EINVAL; else { ff->func = fetch_stack; ff->data = (void *)param; } + } else + ret = -EINVAL; + } else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) { + ret = strict_strtoul(arg + 3, 10, ¶m); + if (ret || param > PARAM_MAX_ARGS) + ret = -EINVAL; + else { + ff->func = fetch_argument; + ff->data = (void *)param; } - break; - default: + } else ret = -EINVAL; - } return ret; } @@ -548,10 +544,10 @@ static int create_trace_probe(int argc, char **argv) * - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS] * Fetch args: - * $aN : fetch Nth of function argument. (N:0-) - * $rv : fetch return value - * $sa : fetch stack address - * $sN : fetch Nth of stack (N:0-) + * $argN : fetch Nth of function argument. (N:0-) + * $retval : fetch return value + * $stack : fetch stack address + * $stackN : fetch Nth of stack (N:0-) * @ADDR : fetch memory at ADDR (ADDR should be in kernel) * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) * %REG : fetch register REG |