From 6c6804fb2cef2d6aceb38b0eb0803210d77ff390 Mon Sep 17 00:00:00 2001 From: Andrew Lutomirski Date: Thu, 24 Mar 2011 00:36:56 -0400 Subject: perf symbols: Fix vsyscall symbol lookup Perf can't currently trace into the vsyscall page. It looks like it was meant to work. Tested on 2.6.38 and today's -git. The bug is easy to reproduce. Compile this: int main() { int i; struct timespec t; for(i = 0; i < 10000000; i++) clock_gettime(CLOCK_MONOTONIC, &t); return 0; } and run it through perf record; perf report. The top entry shows "[unknown]" and you can't zoom in. It looks like there are two issues. The first is a that a test for user mode executing in kernel space is backwards. (That's the first hunk below). The second (I think) is that something's wrong with the code that generates lots of little struct dso objects for different sections -- when it runs on vmlinux it results in bogus long_name values which cause objdump to fail. Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra LPU-Reference: Signed-off-by: Andy Lutomirski Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.c | 2 +- tools/perf/util/symbol.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 2b15c362ef5..1023f67633a 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -710,7 +710,7 @@ try_again: * in the whole kernel symbol list. */ if ((long long)al->addr < 0 && - cpumode == PERF_RECORD_MISC_KERNEL && + cpumode == PERF_RECORD_MISC_USER && machine && mg != &machine->kmaps) { mg = &machine->kmaps; goto try_again; diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 17df793c892..8f73907a959 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1196,6 +1196,8 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name, if (curr_dso == NULL) goto out_elf_end; curr_dso->kernel = self->kernel; + curr_dso->long_name = self->long_name; + curr_dso->long_name_len = self->long_name_len; curr_map = map__new2(start, curr_dso, map->type); if (curr_map == NULL) { @@ -1842,6 +1844,7 @@ int dso__load_vmlinux(struct dso *self, struct map *map, if (fd < 0) return -1; + dso__set_long_name(self, (char *)vmlinux); dso__set_loaded(self, map->type); err = dso__load_sym(self, map, symfs_vmlinux, fd, filter, 0, 0); close(fd); -- cgit v1.2.3-18-g5258