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4da8b12188
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:
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| .. | ||
| alpha | ||
| arc/annotate | ||
| arm | ||
| arm64 | ||
| csky | ||
| mips | ||
| nds32 | ||
| parisc | ||
| powerpc | ||
| riscv | ||
| s390 | ||
| sh | ||
| sparc | ||
| x86 | ||
| xtensa | ||
| Build | ||
| common.c | ||
| common.h | ||