6.5-stable review patch. If anyone has any objections, please let me know.
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From: Arnaldo Carvalho de Melo acme@redhat.com
[ Upstream commit ef23cb593304bde0cc046fd4cc83ae7ea2e24f16 ]
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.
The same problem was found in 'perf top' after an audit of all perf_session__new() failure handling.
Fixes: 6ef81c55a2b6584c ("perf session: Return error code for perf_session__new() function on failure") Cc: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Alexey Budankov alexey.budankov@linux.intel.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Jeremie Galarneau jeremie.galarneau@efficios.com Cc: Jiri Olsa jolsa@kernel.org Cc: Kate Stewart kstewart@linuxfoundation.org Cc: Mamatha Inamdar mamatha4@linux.vnet.ibm.com Cc: Mukesh Ojha mojha@codeaurora.org Cc: Nageswara R Sastry rnsastry@linux.vnet.ibm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Ravi Bangoria ravi.bangoria@linux.ibm.com Cc: Shawn Landden shawn@git.icu Cc: Song Liu songliubraving@fb.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Tzvetomir Stoyanov tstoyanov@vmware.com Link: https://lore.kernel.org/lkml/ZN4Q2rxxsL08A8rd@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/builtin-top.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 1baa2acb3cedd..ea8c7eca5eeed 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1805,6 +1805,7 @@ int cmd_top(int argc, const char **argv) top.session = perf_session__new(NULL, NULL); if (IS_ERR(top.session)) { status = PTR_ERR(top.session); + top.session = NULL; goto out_delete_evlist; }