diff options
| -rw-r--r-- | kernel/trace/blktrace.c | 59 |
1 files changed, 54 insertions, 5 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 776ae4190f36..e4f26ddb7ee2 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -384,16 +384,65 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, buffer = blk_tr->array_buffer.buffer; trace_ctx = tracing_gen_ctx_flags(0); - trace_len = sizeof(struct blk_io_trace2) + pdu_len + cgid_len; + switch (bt->version) { + case 1: + trace_len = sizeof(struct blk_io_trace); + break; + case 2: + default: + /* + * ftrace always uses v2 (blk_io_trace2) format. + * + * For sysfs-enabled tracing path (enabled via + * /sys/block/DEV/trace/enable), blk_trace_setup_queue() + * never initializes bt->version, leaving it 0 from + * kzalloc(). We must handle version==0 safely here. + * + * Fall through to default to ensure we never hit the + * old bug where default set trace_len=0, causing + * buffer underflow and memory corruption. + * + * Always use v2 format for ftrace and normalize + * bt->version to 2 when uninitialized. + */ + trace_len = sizeof(struct blk_io_trace2); + if (bt->version == 0) + bt->version = 2; + break; + } + trace_len += pdu_len + cgid_len; event = trace_buffer_lock_reserve(buffer, TRACE_BLK, trace_len, trace_ctx); if (!event) return; - record_blktrace_event(ring_buffer_event_data(event), - pid, cpu, sector, bytes, - what, bt->dev, error, cgid, cgid_len, - pdu_data, pdu_len); + switch (bt->version) { + case 1: + record_blktrace_event(ring_buffer_event_data(event), + pid, cpu, sector, bytes, + what, bt->dev, error, cgid, cgid_len, + pdu_data, pdu_len); + break; + case 2: + default: + /* + * Use v2 recording function (record_blktrace_event2) + * which writes blk_io_trace2 structure with correct + * field layout: + * - 32-bit pid at offset 28 + * - 64-bit action at offset 32 + * + * Fall through to default handles version==0 case + * (from sysfs path), ensuring we always use correct + * v2 recording function to match the v2 buffer + * allocated above. + */ + record_blktrace_event2(ring_buffer_event_data(event), + pid, cpu, sector, bytes, + what, bt->dev, error, cgid, cgid_len, + pdu_data, pdu_len); + break; + } trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx); return; |