From c4c1dbcc09e723295969a62aff401815b7ee15f4 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 18 Nov 2021 12:22:17 -0800 Subject: [PATCH] tracing: Use memset_startat() to zero struct trace_iterator In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Use memset_startat() to avoid confusing memset() about writing beyond the target struct member. Link: https://lkml.kernel.org/r/20211118202217.1285588-1-keescook@chromium.org Signed-off-by: Kees Cook Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f9139dc1262c..e3c80cfd4eec 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6706,9 +6706,7 @@ waitagain: cnt = PAGE_SIZE - 1; /* reset all but tr, trace, and overruns */ - memset(&iter->seq, 0, - sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + memset_startat(iter, 0, seq); cpumask_clear(iter->started); trace_seq_init(&iter->seq); iter->pos = -1;