5.10-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Raillard douglas.raillard@arm.com
[ Upstream commit 4d38328eb442dc06aec4350fd9594ffa6488af02 ]
The printk format for synth event uses "%.*s" to print string fields, but then only passes the pointer part as var arg.
Replace %.*s with %s as the C string is guaranteed to be null-terminated.
The output in print fmt should never have been updated as __get_str() handles the string limit because it can access the length of the string in the string meta data that is saved in the ring buffer.
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Fixes: 8db4d6bfbbf92 ("tracing: Change synthetic event string format to limit printed length") Link: https://lore.kernel.org/20250325165202.541088-1-douglas.raillard@arm.com Signed-off-by: Douglas Raillard douglas.raillard@arm.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace_events_synth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 4878758ceea2a..613d45e7b608d 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -290,7 +290,7 @@ static const char *synth_field_fmt(char *type) else if (strcmp(type, "gfp_t") == 0) fmt = "%x"; else if (synth_field_is_string(type)) - fmt = "%.*s"; + fmt = "%s"; else if (synth_field_is_stack(type)) fmt = "%s";