[PATCH 1/2] trace-cmd: Don't try to read unmapped memory (v2).
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From: David Daney on 19 Jul 2010 20:50 Under some circumstances, I'm not sure exactly which, a trace.dat file may contain a bunch of zeros at the end of one or more of the trace logs. This can lead to tracecmd_peek_data() attempting to read past the end of the mmaped log, causing SIGSEGV. This is a two part fix. 1) For 'new format' data, we always try to read 8 bytes of data. Make sure that they are all on the current page. 2) In pevent_print_event(), if record->size is negative, warn and then skip attempting to print it. Signed-off-by: David Daney <ddaney(a)caviumnetworks.com> --- parse-events.c | 5 +++++ trace-input.c | 3 ++- 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/parse-events.c b/parse-events.c index 16fff12..52b68f0 100644 --- a/parse-events.c +++ b/parse-events.c @@ -3881,6 +3881,11 @@ void pevent_print_event(struct pevent *pevent, struct trace_seq *s, usecs = record->ts - secs * NSECS_PER_SEC; usecs = (usecs + 500) / NSECS_PER_USEC; + if (record->size < 0) { + do_warning("ug! negative record size %d", record->size); + return; + } + type = trace_parse_common_type(pevent, data); event = pevent_find_event(pevent, type); diff --git a/trace-input.c b/trace-input.c index 398d0f9..7241197 100644 --- a/trace-input.c +++ b/trace-input.c @@ -1511,7 +1511,8 @@ read_again: if (index < 0) die("negative index on cpu record %d", cpu); - if (index >= handle->cpu_data[cpu].page_size + pevent->header_page_data_offset) { + if (index + (pevent->old_format ? 0 : 4) >= + handle->cpu_data[cpu].page_size + pevent->header_page_data_offset) { if (get_next_page(handle, cpu)) return NULL; return tracecmd_peek_data(handle, cpu); -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |