From 935f5a9d4500020879858c9224c98dfabf16101d Mon Sep 17 00:00:00 2001 From: Jin Yao Date: Sat, 30 Dec 2017 00:26:52 +0800 Subject: perf report: Fix a wrong offset issue when using /proc/kcore When a valid vmlinux is not found, 'perf report' falls back to look at /proc/kcore. In this case, it will report the impossible large offset. For example: # perf record -b -e cycles:k find /etc/ > /dev/null # perf report --stdio --branch-history 22.77% _vm_normal_page+18446603336221188162 | ---page_remove_rmap +18446603336221188324 page_remove_rmap +18446603336221188487 (cycles:5) unlock_page_memcg +18446603336221188096 page_remove_rmap +18446603336221188327 (cycles:1) The issue is the value which is passed to parameter 'addr' in __get_srcline() is the objdump address. It's not correct if we calculate the offset by using 'addr - sym->start'. This patch creates a new parameter 'ip' in __get_srcline(). It is not converted to objdump address. With this patch, the perf report output is: 22.77% _vm_normal_page+66 | ---page_remove_rmap +228 page_remove_rmap +391 (cycles:5) unlock_page_memcg +0 page_remove_rmap +231 (cycles:1) page_remove_rmap +236 Committer testing: Make sure you get any valid vmlinux out of the way, using '-v' on the 'perf report' case and deleting it from places where perf searches them, like your kernel build dir and the build-id cache, in ~/.debug/. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Jin Yao Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Andi Kleen Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1514564812-17344-1-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/srcline.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'tools/perf/util/srcline.c') diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c index d19f05c..3c21fd0 100644 --- a/tools/perf/util/srcline.c +++ b/tools/perf/util/srcline.c @@ -496,7 +496,8 @@ out: #define A2L_FAIL_LIMIT 123 char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym, - bool show_sym, bool show_addr, bool unwind_inlines) + bool show_sym, bool show_addr, bool unwind_inlines, + u64 ip) { char *file = NULL; unsigned line = 0; @@ -536,7 +537,7 @@ out: if (sym) { if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "", - addr - sym->start) < 0) + ip - sym->start) < 0) return SRCLINE_UNKNOWN; } else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0) return SRCLINE_UNKNOWN; @@ -550,9 +551,9 @@ void free_srcline(char *srcline) } char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym, - bool show_sym, bool show_addr) + bool show_sym, bool show_addr, u64 ip) { - return __get_srcline(dso, addr, sym, show_sym, show_addr, false); + return __get_srcline(dso, addr, sym, show_sym, show_addr, false, ip); } struct srcline_node { -- cgit v1.1