6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Arnaldo Carvalho de Melo acme@redhat.com
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@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Ian Rogers irogers@google.com Cc: Ingo Molnar mingo@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: K Prateek Nayak kprateek.nayak@amd.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Leo Yan leo.yan@linaro.org Cc: Mamatha Inamdar mamatha4@linux.vnet.ibm.com Cc: Mark Rutland mark.rutland@arm.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Paolo Bonzini pbonzini@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ravi Bangoria ravi.bangoria@amd.com Cc: Ross Zwisler zwisler@chromium.org Cc: Sean Christopherson seanjc@google.com Cc: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Tiezhu Yang yangtiezhu@loongson.cn Cc: Yang Jihong yangjihong1@huawei.com Link: https://lore.kernel.org/lkml/ZN4R1AYfsD2J8lRs@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }