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Subject[PATCH] trace-cmd: Don't SIGSEGV when event field format cannot be parsed.
From the MIPS kernel we get things like:

print fmt: "page=%p pfn=%lu order=%d migratetype=%d", REC->page, ({ struct page *__pg = (REC->page); int __sec = page_to_section(__pg); (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); }), REC->order, REC->migratetype

This cannot be parsed, leading to a NULL struct event_format* being
passed to pevent_get_common_field_val, which produces a SIGSEGV. It
would be good to get a parsable format from the kernel, but to
remediate the problem for legacy kernels, we can just return an error
indicator in this case. This allows some output from trace-cmd
report, although perhaps with some missing data. But this is better
than crashing.

Signed-off-by: David Daney <>
parse-events.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/parse-events.c b/parse-events.c
index 9d5a3fa..16fff12 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -4481,6 +4481,9 @@ int pevent_get_common_field_val(struct trace_seq *s, struct event_format *event,
struct format_field *field;

+ if (!event)
+ return -1;
field = pevent_find_common_field(event, name);

return get_field_val(s, field, name, record, val, err);

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