linux-sg2042/tools/perf/util
Milos Vyletel 0635b0f714 perf tools: Fix race in build_id_cache__add_s()
int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
                          const char *name, bool is_kallsyms, bool is_vdso)
{
...
        if (access(filename, F_OK)) {
               ^--------------------------------------------------------- [1]
                if (is_kallsyms) {
                         if (copyfile("/proc/kallsyms", filename))
                                goto out_free;
                } else if (link(realname, filename) && copyfile(name, filename))
                             ^-----------------------------^------------- [2]
                                                            \------------ [3]
                        goto out_free;
        }
...

When multiple instances of perf record get to [1] at more or less same time and
run access() one or more may get failure because the file does not exist yet
(since the first instance did not have chance to link it yet).

At this point the race moves to link() at [2] where first thread to get
there links file and goes on but second one gets -EEXIST so it runs
copyfile [3] which truncates the file.

reproducer:

rm -rf /root/.debug
for cpu in $(awk '/processor/ {print $3}' /proc/cpuinfo); do
	perf record -a -v -T -F 1000 -C $cpu \
		-o perf-${cpu}.data sleep 5 2> /dev/null &
done
wait

and simply search for empty files by:

find /lib/modules/`uname -r`/kernel/* -size 0

Signed-off-by: Milos Vyletel <milos@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1426847846-11112-1-git-send-email-milos@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-20 17:49:50 -03:00
..
include tools: Remove bitops/hweight usage of bits in tools/perf 2015-01-16 17:49:29 -03:00
scripting-engines perf build: Add scripts objects building 2015-02-12 11:49:53 -03:00
Build perf tools: Only include tsc file for x86 2015-03-02 11:50:08 -03:00
PERF-VERSION-GEN perf tools: Fix version when building out of tree 2013-11-07 10:40:47 -03:00
abspath.c
alias.c perf tools: Introduce zfree 2013-12-27 15:17:00 -03:00
annotate.c perf tools: Remove EOL whitespaces 2015-01-21 13:24:31 -03:00
annotate.h perf tools: Fix segfault for symbol annotation on TUI 2015-01-16 17:49:29 -03:00
bitmap.c perf tools: Add bitmap_or function into bitmap object 2012-02-13 23:28:10 -02:00
build-id.c perf tools: Fix race in build_id_cache__add_s() 2015-03-20 17:49:50 -03:00
build-id.h perf buildid-cache: Add --purge FILE to remove all caches of FILE 2015-02-27 15:52:33 -03:00
cache.h perf tools: Make perf aware of tracefs 2015-02-11 12:37:08 -03:00
callchain.c perf tools: Enable LBR call stack support 2015-02-18 17:16:17 +01:00
callchain.h perf tools: Enable LBR call stack support 2015-02-18 17:16:17 +01:00
cgroup.c perf evlist: Introduce evlist__for_each() & friends 2014-01-13 10:06:25 -03:00
cgroup.h perf tool: Add cgroup support 2011-02-16 13:30:48 +01:00
cloexec.c perf tools: Fix probing for PERF_FLAG_FD_CLOEXEC flag 2015-02-25 16:40:13 -03:00
cloexec.h perf tools: Enable close-on-exec flag on perf file descriptor 2014-07-18 09:09:34 +02:00
color.c perf tools: Remove some unused functions from color.c 2015-01-21 13:24:32 -03:00
color.h perf tools: Remove some unused functions from color.c 2015-01-21 13:24:32 -03:00
comm.c perf tools: Identify which comms are from exec 2014-08-13 19:23:08 -03:00
comm.h perf tools: Add facility to export data in database-friendly way 2014-10-29 10:32:49 -02:00
config.c perf tools: Add --buildid-dir option to set cache directory 2014-12-09 09:14:35 -03:00
cpumap.c perf tools: Use cpu/possible instead of cpu/kernel_max 2014-04-22 17:39:16 +02:00
cpumap.h perf tools: Allow ability to map cpus to nodes easily 2014-04-22 17:39:12 +02:00
ctype.c perf tools: ctype.c only wants util.h 2012-02-13 23:17:40 -02:00
data-convert-bt.c perf data: Add tracepoint events fields CTF conversion support 2015-03-13 07:47:49 -03:00
data-convert-bt.h perf data: Add perf data to CTF conversion support 2015-02-25 16:13:12 -03:00
data.c perf util: Replace strerror with strerror_r for thread-safety 2014-08-15 10:58:35 -03:00
data.h perf tools: Add perf_data_file__write interface 2013-12-02 09:22:46 -03:00
db-export.c perf tools: Defer export of comms that were not 'set' 2014-11-03 18:11:59 -03:00
db-export.h perf tools: Defer export of comms that were not 'set' 2014-11-03 18:11:59 -03:00
debug.c perf data: Add perf data to CTF conversion support 2015-02-25 16:13:12 -03:00
debug.h perf data: Add perf data to CTF conversion support 2015-02-25 16:13:12 -03:00
dso.c perf symbols: debuglink should take symfs option into account 2015-02-06 11:46:36 +01:00
dso.h perf callchain: Separate eh/debug frame offset cache. 2015-03-19 13:53:27 -03:00
dwarf-aux.c perf probe: Fix to handle optimized not-inlined functions 2015-02-06 11:46:36 +01:00
dwarf-aux.h perf probe: Fix to handle optimized not-inlined functions 2015-02-06 11:46:36 +01:00
environment.c
event.c perf tools: Fix FORK after COMM when synthesizing records for pre-existing threads 2015-03-02 11:51:30 -03:00
event.h Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-12-09 21:18:06 -08:00
evlist.c perf evlist: Introduce set_filter_pids method 2015-02-22 22:21:27 -03:00
evlist.h Merge 'tip/perf/urgent' into perf/core to pick fixes 2015-03-02 11:45:49 -03:00
evsel.c perf record: Support recording running/enabled time 2015-02-25 12:42:23 -03:00
evsel.h perf tools: Construct LBR call chain 2015-02-18 17:16:18 +01:00
exec_cmd.c perf tools: Makefile: Remove various and sundry cruft 2011-02-18 07:43:06 -02:00
exec_cmd.h
find-vdso-map.c perf tools: Build programs to copy 32-bit compatibility 2014-10-29 10:32:48 -02:00
generate-cmdlist.sh tools/perf: Standardize feature support define names to: HAVE_{FEATURE}_SUPPORT 2013-10-09 08:48:28 +02:00
header.c perf header: Set header version correctly 2015-01-29 16:53:11 -03:00
header.h perf build-id: Move build-id related functions to util/build-id.c 2014-11-05 10:14:07 -03:00
help.c perf tools: Use zfree to help detect use after free bugs 2013-12-27 17:08:19 -03:00
help.h
hist.c perf hists: Remove hist_entry->used, not used anymore 2015-03-17 17:18:58 -03:00
hist.h perf hists browser: Allow annotating entries in callchains 2015-03-17 18:27:28 -03:00
intlist.c perf util: Add findnew method to intlist 2013-10-14 10:28:48 -03:00
intlist.h perf util: Add findnew method to intlist 2013-10-14 10:28:48 -03:00
kvm-stat.h perf kvm stat report: Save pid string in opts.target.pid 2014-09-17 17:08:07 -03:00
levenshtein.c
levenshtein.h
machine.c perf tools: Reference count struct thread 2015-03-03 00:17:08 -03:00
machine.h perf tools: Reference count struct thread 2015-03-03 00:17:08 -03:00
map.c perf callchain: Make get_srcline fall back to sym+offset 2014-11-24 18:03:47 -03:00
map.h perf symbols: Introduce 'for' method to iterate over the symbols with a given name 2015-01-21 10:06:15 -03:00
ordered-events.c perf ordered_events: Adopt queue() method 2015-03-12 12:39:51 -03:00
ordered-events.h perf ordered_events: Adopt queue() method 2015-03-12 12:39:51 -03:00
pager.c perf tools: Add cat as fallback pager 2014-05-21 11:48:33 +02:00
parse-events.c perf list: Clean up the printing functions of hardware/software events 2015-02-27 15:52:18 -03:00
parse-events.h perf list: Clean up the printing functions of hardware/software events 2015-02-27 15:52:18 -03:00
parse-events.l perf tools: allow user to specify hardware breakpoint bp_len 2014-12-03 15:14:29 +01:00
parse-events.y perf tools: allow user to specify hardware breakpoint bp_len 2014-12-03 15:14:29 +01:00
parse-options.c perf report: Don't allow empty argument for '-t'. 2015-03-19 13:53:28 -03:00
parse-options.h perf report: Don't allow empty argument for '-t'. 2015-03-19 13:53:28 -03:00
path.c tools/perf: Turn strlcpy() into a __weak function 2013-10-09 08:48:49 +02:00
perf_regs.c perf tools: Cache register accesses for unwind processing 2014-06-12 16:53:19 +02:00
perf_regs.h perf tools: Cache register accesses for unwind processing 2014-06-12 16:53:19 +02:00
pmu.c perf tools: Extend format_alias() to include event parameters 2015-01-21 13:24:33 -03:00
pmu.h perf tools: Add snapshot format file parsing 2014-11-24 18:03:51 -03:00
pmu.l perf tools: Add perf pmu object to access pmu format definition 2012-03-16 14:29:35 -03:00
pmu.y perf tools: Fix build with bison 2.3 and older. 2013-02-14 16:12:34 -03:00
probe-event.c perf probe: Fix compiles due to declarations using perf_probe_point 2015-03-12 12:40:00 -03:00
probe-event.h perf probe: Do not access kallsyms when analyzing user binaries 2014-09-17 18:01:14 -03:00
probe-finder.c perf probe: Remove bias offset to find probe point by address 2015-03-02 12:34:38 -03:00
probe-finder.h perf probe: Support distro-style debuginfo for uprobe 2014-02-18 09:38:44 -03:00
pstack.c perf tools: Move pr_* debug macros into debug object 2014-07-17 12:58:39 -03:00
pstack.h perf tools: Finish the removal of 'self' arguments 2013-11-05 15:32:36 -03:00
python-ext-sources perf tools: Remove api fs object from python build 2015-02-12 11:22:01 -03:00
python.c perf tools: Remove EOL whitespaces 2015-01-21 13:24:31 -03:00
quote.c
quote.h
rblist.c perf util: Add findnew method to intlist 2013-10-14 10:28:48 -03:00
rblist.h perf util: Add findnew method to intlist 2013-10-14 10:28:48 -03:00
record.c perf tools: Use sysctl__read_int instead of ad-hoc copies 2014-12-11 17:53:04 -03:00
run-command.c perf util: Replace strerror with strerror_r for thread-safety 2014-08-15 10:58:35 -03:00
run-command.h
session.c perf ordered_events: Adopt queue() method 2015-03-12 12:39:51 -03:00
session.h perf ordered_events: Allow tools to specify a deliver method 2015-03-12 12:39:46 -03:00
setup.py tools lib api: Rename libapikfs.a to libapi.a 2015-02-12 17:55:18 -03:00
sigchain.c
sigchain.h
sort.c perf diff: Support for different binaries 2015-02-27 10:08:38 -03:00
sort.h perf hists: Remove hist_entry->used, not used anymore 2015-03-17 17:18:58 -03:00
srcline.c perf: Fix building warning on ARM 32 2014-12-19 13:09:43 +01:00
stat.c perf stats: Add max and min stats 2013-08-07 17:35:26 -03:00
stat.h tools: Consolidate types.h 2014-05-01 21:22:39 +02:00
strbuf.c perf tools: Use zfree to help detect use after free bugs 2013-12-27 17:08:19 -03:00
strbuf.h
strfilter.c perf tools: Use zfree to help detect use after free bugs 2013-12-27 17:08:19 -03:00
strfilter.h perf tools: Finish the removal of 'self' arguments 2013-11-05 15:32:36 -03:00
string.c Revert "perf tools: Default to cpu// for events v5" 2014-10-15 16:04:33 -03:00
strlist.c perf tools: Fix build error due to zfree() cast 2014-01-15 15:10:04 -03:00
strlist.h perf tools: Stop using 'self' in strlist 2013-01-25 12:49:28 -03:00
svghelper.c perf timechart: Implement IO mode 2014-07-10 00:22:54 +02:00
svghelper.h perf timechart: Implement IO mode 2014-07-10 00:22:54 +02:00
symbol-elf.c perf symbols: Allow symbol alias when loading map for symbol name 2015-03-12 12:39:54 -03:00
symbol-minimal.c perf symbols: Fix use after free in filename__read_build_id 2014-12-17 11:58:17 -03:00
symbol.c perf tools: Remove EOL whitespaces 2015-01-21 13:24:31 -03:00
symbol.h perf symbols: Allow symbol alias when loading map for symbol name 2015-03-12 12:39:54 -03:00
target.c perf record: Make per-cpu mmaps the default. 2013-11-27 14:58:36 -03:00
target.h perf target: Move the checking of which map function to call into function. 2013-12-04 13:46:37 -03:00
thread-stack.c perf tools: Enhance the thread stack to output call/return data 2014-11-03 17:43:56 -03:00
thread-stack.h perf tools: Enhance the thread stack to output call/return data 2014-11-03 17:43:56 -03:00
thread.c perf tools: Remove superfluous thread->comm_set setting 2015-03-12 12:39:50 -03:00
thread.h perf tools: Reference count struct thread 2015-03-03 00:17:08 -03:00
thread_map.c perf thread_map: Create dummy constructor out of open coded equivalent 2014-10-14 17:32:52 -03:00
thread_map.h perf thread_map: Create dummy constructor out of open coded equivalent 2014-10-14 17:32:52 -03:00
tool.h perf tools: tool->finished_round() doesn't need perf_session 2015-03-12 12:39:49 -03:00
top.c perf tools: Rename 'perf_record_opts' to 'record_opts 2013-12-19 14:43:45 -03:00
top.h tools: Consolidate types.h 2014-05-01 21:22:39 +02:00
trace-event-info.c perf tools: Move pr_* debug macros into debug object 2014-07-17 12:58:39 -03:00
trace-event-parse.c perf tools: Introduce event_format__fprintf method 2015-02-06 11:46:37 +01:00
trace-event-read.c perf tools: Remove needless getopt.h includes 2014-07-17 12:59:00 -03:00
trace-event-scripting.c perf scripting: Add 'flush' callback to scripting API 2014-08-22 13:12:11 -03:00
trace-event.c tools lib traceevent: Make plugin unload function receive pevent 2014-01-15 15:10:40 -03:00
trace-event.h perf tools: Introduce event_format__fprintf method 2015-02-06 11:46:37 +01:00
tsc.c perf tools: Move rdtsc() function 2014-07-23 11:48:11 -03:00
tsc.h perf tools: Move rdtsc() function 2014-07-23 11:48:11 -03:00
unwind-libdw.c perf callchains: Use thread->mg->machine 2014-10-29 10:32:46 -02:00
unwind-libdw.h perf tools: Add libdw DWARF post unwind support 2014-02-24 09:29:36 -03:00
unwind-libunwind.c perf callchain: Separate eh/debug frame offset cache. 2015-03-19 13:53:27 -03:00
unwind.h perf callchains: Use thread->mg->machine 2014-10-29 10:32:46 -02:00
usage.c perf target: Introduce perf_target__parse_uid() 2012-05-07 16:46:48 -03:00
util.c perf tools: Introduce dump_stack signal helper 2015-02-24 15:34:23 -03:00
util.h perf tools: Introduce dump_stack signal helper 2015-02-24 15:34:23 -03:00
values.c perf tools: Use zfree to help detect use after free bugs 2013-12-27 17:08:19 -03:00
values.h tools: Consolidate types.h 2014-05-01 21:22:39 +02:00
vdso.c perf tools: Do not attempt to run perf-read-vdso32 if it wasn't built 2014-10-29 10:32:48 -02:00
vdso.h perf tools: Add support for 32-bit compatibility VDSOs 2014-10-29 10:32:48 -02:00
wrapper.c perf tools: Use __maybe_used for unused variables 2012-09-11 12:19:15 -03:00
xyarray.c perf tools: Introduce event selectors 2011-01-03 16:39:04 -02:00
xyarray.h perf tools: Introduce event selectors 2011-01-03 16:39:04 -02:00
zlib.c perf tools: Add gzip decompression support for kernel module 2014-11-05 10:11:26 -03:00