Commit-ID: c58c49ac630979a285d574b3f72a528209515fb3
Gitweb: http://git.kernel.org/tip/c58c49ac630979a285d574b3f72a528209515fb3
Author: Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Tue, 7 Jun 2016 03:54:38 +0000
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 7 Jun 2016 10:49:41 -0300
perf tools: Fix crash in build_id_cache__kallsyms_path()
build_id_cache__kallsyms_path() accepts a string buffer but also allocs
a buffer using asnprintf. Unfortunately, the its only user passes it a
stack-allocated buffer. Freeing it causes crashes like this:
$ perf script
*** Error in `/home/wangnan/perf': free(): invalid pointer: 0x00007fffffff9630 ***
======= Backtrace: =========
lib64/libc.so.6(+0x6eeef)[0x7ffff5dbaeef]
lib64/libc.so.6(+0x78cae)[0x7ffff5dc4cae]
lib64/libc.so.6(+0x79987)[0x7ffff5dc5987]
/home/w00229757/perf(build_id_cache__kallsyms_path+0x6b)[0x49681b]
/home/w00229757/perf[0x4bdd40]
/home/w00229757/perf(dso__load+0xa3a)[0x4c048a]
/home/w00229757/perf(map__load+0x6f)[0x4d561f]
/home/w00229757/perf(thread__find_addr_map+0x235)[0x49e935]
/home/w00229757/perf(machine__resolve+0x7d)[0x49ec6d]
/home/w00229757/perf[0x4555a8]
/home/w00229757/perf[0x4d9507]
/home/w00229757/perf[0x4d9e80]
/home/w00229757/perf(ordered_events__flush+0x354)[0x4dd444]
/home/w00229757/perf(perf_session__process_events+0x3d0)[0x4dc140]
/home/w00229757/perf(cmd_script+0x12b0)[0x4592e0]
/home/w00229757/perf[0x4911f1]
/home/w00229757/perf(main+0x68f)[0x4352ef]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7ffff5d6dbd5]
/home/w00229757/perf[0x435415]
======= Memory map: ========
This patch simplifies build_id_cache__kallsyms_path(), not even
considering allocating a string buffer, so never frees anything. Its
caller should manage memory allocation.
Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Fixes: 01412261d994 ("perf buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid")
Link: http://lkml.kernel.org/r/1465271678-7392-1-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/build-id.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 67f986c..20aef90 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -147,20 +147,17 @@ static int asnprintf(char **strp, size_t size, const char *fmt, ...)
char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
size_t size)
{
- bool is_alloc = !!bf;
bool retry_old = true;
- asnprintf(&bf, size, "%s/%s/%s/kallsyms",
- buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
+ snprintf(bf, size, "%s/%s/%s/kallsyms",
+ buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
retry:
if (!access(bf, F_OK))
return bf;
- if (is_alloc)
- free(bf);
if (retry_old) {
/* Try old style kallsyms cache */
- asnprintf(&bf, size, "%s/%s/%s",
- buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
+ snprintf(bf, size, "%s/%s/%s",
+ buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
retry_old = false;
goto retry;
}
--
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