4.4-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Olsa jolsa@redhat.com
[ Upstream commit e3ebaa465136ecfedf9c6f4671df02bf625f8125 ]
Jin Yao reported memory corrupton in perf report with branch info used for stack trace:
Following command lines will cause perf crash.
perf record -j call -g -a <application> perf report --branch-history
*** Error in `perf': double free or corruption (!prev): 0x00000000104aa040 *** ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x77725)[0x7f6b37254725] /lib/x86_64-linux-gnu/libc.so.6(+0x7ff4a)[0x7f6b3725cf4a] /lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f6b37260abc] perf[0x51b914] perf(hist_entry_iter__add+0x1e5)[0x51f305] perf[0x43cf01] perf[0x4fa3bf] perf[0x4fa923] perf[0x4fd396] perf[0x4f9614] perf(perf_session__process_events+0x89e)[0x4fc38e] perf(cmd_report+0x15d2)[0x43f202] perf[0x4a059f] perf(main+0x631)[0x427b71] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f6b371fd830] perf(_start+0x29)[0x427d89]
For the cumulative output, we allocate the he_cache array based on the --max-stack option value and populate it with data from 'callchain_cursor'.
The --max-stack option value does not ensure now the limit for number of callchain_cursor nodes, so the cumulative iter code will allocate smaller array than it's actually needed and cause above corruption.
I think the --max-stack limit does not apply here anyway, because we add callchain data as normal hist entries, while the --max-stack control the limit of single entry callchain depth.
Using the callchain_cursor.nr as he_cache array count to fix this. Also removing struct hist_entry_iter::max_stack, because there's no longer any use for it.
We need more fixes to ensure that the branch stack code follows properly the logic of --max-stack, which is not the case at the moment.
Original-patch-by: Jin Yao yao.jin@linux.intel.com Signed-off-by: Jiri Olsa jolsa@kernel.org Reported-by: Jin Yao yao.jin@linux.intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Jiri Olsa jolsa@kernel.org Cc: Kan Liang kan.liang@intel.com Cc: Peter Zijlstra peterz@infradead.org Link: http://lkml.kernel.org/r/20180216123619.GA9945@krava Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/hist.c | 4 +--- tools/perf/util/hist.h | 1 - 2 files changed, 1 insertion(+), 4 deletions(-)
--- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -720,7 +720,7 @@ iter_prepare_cumulative_entry(struct his * cumulated only one time to prevent entries more than 100% * overhead. */ - he_cache = malloc(sizeof(*he_cache) * (iter->max_stack + 1)); + he_cache = malloc(sizeof(*he_cache) * (callchain_cursor.nr + 1)); if (he_cache == NULL) return -ENOMEM;
@@ -881,8 +881,6 @@ int hist_entry_iter__add(struct hist_ent if (err) return err;
- iter->max_stack = max_stack_depth; - err = iter->ops->prepare_entry(iter, al); if (err) goto out; --- a/tools/perf/util/hist.h +++ b/tools/perf/util/hist.h @@ -91,7 +91,6 @@ struct hist_entry_iter { int curr;
bool hide_unresolved; - int max_stack;
struct perf_evsel *evsel; struct perf_sample *sample;