From: Jiri Slaby jslaby@suse.cz
[ Upstream commit f3013f7ed465479e60c1ab1921a5718fc541cc3b ]
'perf trace ls' started crashing after commit d21cb73a9025 on !HAVE_SYSCALL_TABLE_SUPPORT configs (armv7l here) like this:
0 strlen () at ../sysdeps/arm/armv6t2/strlen.S:126 1 0xb6800780 in __vfprintf_internal (s=0xbeff9908, s@entry=0xbeff9900, format=0xa27160 "]: %s()", ap=..., mode_flags=<optimized out>) at vfprintf-internal.c:1688 ... 5 0x0056ecdc in fprintf (__fmt=0xa27160 "]: %s()", __stream=<optimized out>) at /usr/include/bits/stdio2.h:100 6 trace__sys_exit (trace=trace@entry=0xbeffc710, evsel=evsel@entry=0xd968d0, event=<optimized out>, sample=sample@entry=0xbeffc3e8) at builtin-trace.c:2475 7 0x00566d40 in trace__handle_event (sample=0xbeffc3e8, event=<optimized out>, trace=0xbeffc710) at builtin-trace.c:3122 ... 15 main (argc=2, argv=0xbefff6e8) at perf.c:538
It is because memset in trace__read_syscall_info zeroes wrong memory:
1) when initializing for the first time, it does not reset the last id.
2) in other cases, it resets the last id of previous buffer.
ad 1) it causes the crash above as sc->name used in the fprintf above contains garbage.
ad 2) it sets nonexistent from true back to false for id 11 here. Not sure, what the consequences are.
So fix it by introducing a special case for the initial initialization and do the right +1 in both cases.
Fixes: d21cb73a9025 ("perf trace: Grow the syscall table as needed when using libaudit") Signed-off-by: Jiri Slaby jslaby@suse.cz Cc: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Link: http://lore.kernel.org/lkml/20201001093419.15761-1-jslaby@suse.cz Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/builtin-trace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index bea461b6f937b..44a75f234db17 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -1762,7 +1762,11 @@ static int trace__read_syscall_info(struct trace *trace, int id) if (table == NULL) return -ENOMEM;
- memset(table + trace->sctbl->syscalls.max_id, 0, (id - trace->sctbl->syscalls.max_id) * sizeof(*sc)); + // Need to memset from offset 0 and +1 members if brand new + if (trace->syscalls.table == NULL) + memset(table, 0, (id + 1) * sizeof(*sc)); + else + memset(table + trace->sctbl->syscalls.max_id + 1, 0, (id - trace->sctbl->syscalls.max_id) * sizeof(*sc));
trace->syscalls.table = table; trace->sctbl->syscalls.max_id = id;