6.6-stable review patch. If anyone has any objections, please let me know.
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From: Adrian Hunter adrian.hunter@intel.com
[ Upstream commit 70df07838fc1c0acfab3325ae79014e241a88bdf ]
Do not increase the node count unless a node has been successfully read, because it can lead to a segfault if an error occurs.
For example, if perf exceeds the open file limit in memory_node__read(), which, on a test system, could be made to happen by setting the file limit to exactly 32:
Before:
$ ulimit -n 32 $ perf mem record --all-user -- sleep 1 [ perf record: Woken up 1 times to write data ] failed: can't open memory sysfs data perf: Segmentation fault Obtained 14 stack frames. perf(sighandler_dump_stack+0x48) [0x55f4b1f59558] /lib/x86_64-linux-gnu/libc.so.6(+0x42520) [0x7f4ba1c42520] /lib/x86_64-linux-gnu/libc.so.6(free+0x1e) [0x7f4ba1ca53fe] perf(+0x178ff4) [0x55f4b1f48ff4] perf(+0x179a70) [0x55f4b1f49a70] perf(+0x17ef5d) [0x55f4b1f4ef5d] perf(+0x85c0b) [0x55f4b1e55c0b] perf(cmd_record+0xe1d) [0x55f4b1e5920d] perf(cmd_mem+0xc96) [0x55f4b1e80e56] perf(+0x130460) [0x55f4b1f00460] perf(main+0x689) [0x55f4b1e427d9] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7f4ba1c29d90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f4ba1c29e40] perf(_start+0x25) [0x55f4b1e42a25] Segmentation fault (core dumped) $
After:
$ ulimit -n 32 $ perf mem record --all-user -- sleep 1 [ perf record: Woken up 1 times to write data ] failed: can't open memory sysfs data [ perf record: Captured and wrote 0.005 MB perf.data (11 samples) ] $
Fixes: f8e502b9d1b3b197 ("perf header: Ensure bitmaps are freed") Signed-off-by: Adrian Hunter adrian.hunter@intel.com Acked-by: Ian Rogers irogers@google.com Cc: German Gomez german.gomez@arm.com Cc: Ian Rogers irogers@google.com Cc: James Clark james.clark@arm.com Cc: Jiri Olsa jolsa@kernel.org Cc: Leo Yan leo.yan@linaro.org Cc: Namhyung Kim namhyung@kernel.org Link: https://lore.kernel.org/r/20231123075848.9652-2-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/header.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index d812e1e371a7..41032243774e 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1444,7 +1444,9 @@ static int build_mem_topology(struct memory_node **nodesp, u64 *cntp) nodes = new_nodes; size += 4; } - ret = memory_node__read(&nodes[cnt++], idx); + ret = memory_node__read(&nodes[cnt], idx); + if (!ret) + cnt += 1; } out: closedir(dir);