This is a note to let you know that I've just added the patch titled perf trace: Fix segfault when trying to trace events by cgroup to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-trace-fix-segfault-when-trying-to-trace-events-.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1eac0dd9995ad2cca4634e2e0de15821622baf5b Author: Stanislav Ivanichkin <sivanichkin@xxxxxxxxxxxxxx> Date: Tue Oct 27 12:43:57 2020 +0300 perf trace: Fix segfault when trying to trace events by cgroup [ Upstream commit a6293f36ac92ab513771a98efe486477be2f981f ] # ./perf trace -e sched:sched_switch -G test -a sleep 1 perf: Segmentation fault Obtained 11 stack frames. ./perf(sighandler_dump_stack+0x43) [0x55cfdc636db3] /lib/x86_64-linux-gnu/libc.so.6(+0x3efcf) [0x7fd23eecafcf] ./perf(parse_cgroups+0x36) [0x55cfdc673f36] ./perf(+0x3186ed) [0x55cfdc70d6ed] ./perf(parse_options_subcommand+0x629) [0x55cfdc70e999] ./perf(cmd_trace+0x9c2) [0x55cfdc5ad6d2] ./perf(+0x1e8ae0) [0x55cfdc5ddae0] ./perf(+0x1e8ded) [0x55cfdc5ddded] ./perf(main+0x370) [0x55cfdc556f00] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6) [0x7fd23eeadb96] ./perf(_start+0x29) [0x55cfdc557389] Segmentation fault # It happens because "struct trace" in option->value is passed to the parse_cgroups function instead of "struct evlist". Fixes: 9ea42ba4411ac ("perf trace: Support setting cgroups as targets") Signed-off-by: Stanislav Ivanichkin <sivanichkin@xxxxxxxxxxxxxx> Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Dmitry Monakhov <dmtrmonakhov@xxxxxxxxxxxxxx> Link: http://lore.kernel.org/lkml/20201027094357.94881-1-sivanichkin@xxxxxxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index bb5130d021554..a5201de1a191d 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -3979,9 +3979,9 @@ do_concat: err = 0; if (lists[0]) { - struct option o = OPT_CALLBACK('e', "event", &trace->evlist, "event", - "event selector. use 'perf list' to list available events", - parse_events_option); + struct option o = { + .value = &trace->evlist, + }; err = parse_events_option(&o, lists[0], 0); } out: @@ -3995,9 +3995,12 @@ static int trace__parse_cgroups(const struct option *opt, const char *str, int u { struct trace *trace = opt->value; - if (!list_empty(&trace->evlist->core.entries)) - return parse_cgroups(opt, str, unset); - + if (!list_empty(&trace->evlist->core.entries)) { + struct option o = { + .value = &trace->evlist, + }; + return parse_cgroups(&o, str, unset); + } trace->cgroup = evlist__findnew_cgroup(trace->evlist, str); return 0;