6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
commit abaf1e0355abb050f9c11d2d13a513caec80f7ad upstream.
While debugging a segfault on 'perf lock contention' without an
available perf.data file I noticed that it was basically calling:
perf_session__delete(ERR_PTR(-1))
Resulting in:
(gdb) run lock contention
Starting program: /root/bin/perf lock contention
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
failed to open perf.data: No such file or directory (try 'perf record' first)
Initializing perf session failed
Program received signal SIGSEGV, Segmentation fault.
0x00000000005e7515 in auxtrace__free (session=0xffffffffffffffff) at util/auxtrace.c:2858
2858 if (!session->auxtrace)
(gdb) p session
$1 = (struct perf_session *) 0xffffffffffffffff
(gdb) bt
#0 0x00000000005e7515 in auxtrace__free (session=0xffffffffffffffff) at util/auxtrace.c:2858
#1 0x000000000057bb4d in perf_session__delete (session=0xffffffffffffffff) at util/session.c:300
#2 0x000000000047c421 in __cmd_contention (argc=0, argv=0x7fffffffe200) at builtin-lock.c:2161
#3 0x000000000047dc95 in cmd_lock (argc=0, argv=0x7fffffffe200) at builtin-lock.c:2604
#4 0x0000000000501466 in run_builtin (p=0xe597a8 <commands+552>, argc=2, argv=0x7fffffffe200) at perf.c:322
#5 0x00000000005016d5 in handle_internal_command (argc=2, argv=0x7fffffffe200) at perf.c:375
#6 0x0000000000501824 in run_argv (argcp=0x7fffffffe02c, argv=0x7fffffffe020) at perf.c:419
#7 0x0000000000501b11 in main (argc=2, argv=0x7fffffffe200) at perf.c:535
(gdb)
So just set it to NULL after using PTR_ERR(session) to decode the error
as perf_session__delete(NULL) is supported.
Fixes: eef4fee5e52071d5 ("perf lock: Dynamically allocate lockhash_table")
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Mamatha Inamdar <mamatha4@xxxxxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Cc: Ross Zwisler <zwisler@xxxxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Cc: Yang Jihong <yangjihong1@xxxxxxxxxx>
Link: https://lore.kernel.org/lkml/ZN4R1AYfsD2J8lRs@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/builtin-lock.c | 1 +
1 file changed, 1 insertion(+)
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1660,6 +1660,7 @@ static int __cmd_contention(int argc, co
if (IS_ERR(session)) {
pr_err("Initializing perf session failed\n");
err = PTR_ERR(session);
+ session = NULL;
goto out_delete;
}
