Like Xu 4da8b12188 perf iostat: Fix Segmentation fault from NULL 'struct perf_counts_values *' ... If the 'perf iostat' user specifies two or more iio_root_ports and also specifies the cpu(s) by -C which is not *connected to all* the above iio ports, the iostat_print_metric() will run into trouble: For example: $ perf iostat list S0-uncore_iio_0<0000:16> S1-uncore_iio_0<0000:97> # <--- CPU 1 is located in the socket S0 $ perf iostat 0000:16,0000:97 -C 1 -- ls port Inbound Read(MB) Inbound Write(MB) Outbound Read(MB) Outbound Write(MB) ../perf-iostat: line 12: 104418 Segmentation fault (core dumped) perf stat --iostat$DELIMITER$* The core-dump stack says, in the above corner case, the returned (struct perf_counts_values *) count will be NULL, and the caller iostat_print_metric() apparently doesn't not handle this case. 433 struct perf_counts_values *count = perf_counts(evsel->counts, die, 0); 434 435 if (count->run && count->ena) { (gdb) p count $1 = (struct perf_counts_values *) 0x0 The deeper reason is that there are actually no statistics from the user specified pair "iostat 0000:X, -C (disconnected) Y ", but let's fix it with minimum cost by adding a NULL check in the user space. Fixes: f9ed693e8b ("perf stat: Enable iostat mode for x86 platforms") Signed-off-by: Like Xu <likexu@tencent.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210927081115.39568-2-likexu@tencent.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>		2021-09-27 09:41:07 -03:00
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annotate	perf annotate: Add 'ret' (intel disasm style) as an alias for 'retq'	2020-09-04 16:07:30 -03:00
entry/syscalls	tools headers UAPI: Sync files changed by new process_mrelease syscall and the removal of some compat entry points	2021-09-10 11:45:07 -03:00
include	perf tests: Drop __maybe_unused on x86 test declarations	2021-05-21 16:58:30 -03:00
tests	perf tests: Consolidate test__arch_unwind_sample declaration	2021-05-21 16:57:43 -03:00
util	perf iostat: Fix Segmentation fault from NULL 'struct perf_counts_values *'	2021-09-27 09:41:07 -03:00
Build	perf tools: Rename build libperf to perf	2019-02-14 15:18:08 -03:00
Makefile	perf tools: Clean 'generated' directory used for creating the syscall table on x86	2021-03-06 16:54:25 -03:00