Dave Anderson wrote: Subject: [PATCH] crash-trace-command: fix accessing uninitialized data Caspar Zhang reported that trace show -c <CPU> causes seg fault. It's because the path is accessing some uninitialized data and causes seg fault. Reported-by: Caspar Zhang <czhang(a)redhat.com&gt; Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com&gt; --- diff --git a/extensions/trace.c b/extensions/trace.c index 975756b..89eb477 100755 --- a/extensions/trace.c +++ b/extensions/trace.c @@ -279,8 +279,12 @@ static void ftrace_destroy_buffers(struct ring_buffer_per_cpu *buffers) { int i; - for (i = 0; i < nr_cpu_ids; i++) + for (i = 0; i < nr_cpu_ids; i++) { + if (!buffers[i].kaddr) + continue; + free(buffers[i].pages); + } } static int ftrace_init_buffers(struct ring_buffer_per_cpu *buffers, @@ -913,6 +917,7 @@ static int ftrace_dump_event_types(const char *events_path) } struct ring_buffer_per_cpu_stream { + struct ring_buffer_per_cpu *cpu_buffer; ulong *pages; void *curr_page; int available_pages; @@ -929,6 +934,7 @@ int ring_buffer_per_cpu_stream_init(struct ring_buffer_per_cpu *cpu_buffer, { unsigned i, count = 0; + s->cpu_buffer = cpu_buffer; s->curr_page = malloc(PAGESIZE()); if (s->curr_page == NULL) return -1; @@ -1104,9 +1110,7 @@ static void __rbs_destroy(struct ring_buffer_stream *s, int *cpulist, int nr) int cpu; for (cpu = 0; cpu < nr; cpu++) { - if (!global_buffers[cpu].kaddr) - continue; - if (cpulist && !cpulist[cpu]) + if (!s->ss[cpu].cpu_buffer) continue; ring_buffer_per_cpu_stream_destroy(s->ss + cpu); @@ -1132,6 +1136,7 @@ int ring_buffer_stream_init(struct ring_buffer_stream *s, int *cpulist) } for (cpu = 0; cpu < nr_cpu_ids; cpu++) { + s->ss[cpu].cpu_buffer = NULL; s->es[cpu].data = NULL; if (!global_buffers[cpu].kaddr) @@ -1183,7 +1188,7 @@ static int ring_buffer_stream_pop_event(struct ring_buffer_stream *s, if (s->popped_cpu == nr_cpu_ids) { for (cpu = 0; cpu < nr_cpu_ids; cpu++) { - if (!global_buffers[cpu].kaddr) + if (!s->ss[cpu].cpu_buffer) continue; ring_buffer_per_cpu_stream_pop_event(s->ss + cpu,