From be07afe92a09638db9159d2c0794487d66a437a2 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Wed, 26 Aug 2015 10:57:43 +0000 Subject: [PATCH] perf probe: Fix list result when address is zero When manually added uprobe point with zero address, 'perf probe -l' reports error. For example: # echo p:probe_libc/abs_0 /path/to/lib.bin:0x0 arg1=%ax > \ /sys/kernel/debug/tracing/uprobe_events # perf probe -l Error: Failed to show event list. Probing at 0x0 is possible and useful when lib.bin is not a normal shared object but is manually mapped. However, in this case kernel report: # cat /sys/kernel/debug/tracing/uprobe_events p:probe_libc/abs_0 /path/to/lib.bin:0x (null) arg1=%ax This patch supports the above kernel output. Signed-off-by: Wang Nan Acked-by: Masami Hiramatsu Cc: Namhyung Kim Cc: Steven Rostedt Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1440586666-235233-5-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-event.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index f7bacbb98865..926bcecc4a44 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -1519,9 +1519,31 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev) } else p = argv[1]; fmt1_str = strtok_r(p, "+", &fmt); - if (fmt1_str[0] == '0') /* only the address started with 0x */ - tp->address = strtoul(fmt1_str, NULL, 0); - else { + /* only the address started with 0x */ + if (fmt1_str[0] == '0') { + /* + * Fix a special case: + * if address == 0, kernel reports something like: + * p:probe_libc/abs_0 /lib/libc-2.18.so:0x (null) arg1=%ax + * Newer kernel may fix that, but we want to + * support old kernel also. + */ + if (strcmp(fmt1_str, "0x") == 0) { + if (!argv[2] || strcmp(argv[2], "(null)")) { + ret = -EINVAL; + goto out; + } + tp->address = 0; + + free(argv[2]); + for (i = 2; argv[i + 1] != NULL; i++) + argv[i] = argv[i + 1]; + + argv[i] = NULL; + argc -= 1; + } else + tp->address = strtoul(fmt1_str, NULL, 0); + } else { /* Only the symbol-based probe has offset */ tp->symbol = strdup(fmt1_str); if (tp->symbol == NULL) {