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[v3,5/6] ftrace: Update the mcount_loc check of skipped entries

Message ID 20250213162146.158076547@goodmis.org (mailing list archive)
State Superseded
Headers show
Series scripts/sorttable: ftrace: Remove place holders for weak functions in available_filter_functions | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Steven Rostedt Feb. 13, 2025, 4:20 p.m. UTC 
From: Steven Rostedt <rostedt@goodmis.org>

Now that weak functions turn into skipped entries, update the check to
make sure the amount that was allocated would fit both the entries that
were allocated as well as those that were skipped.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e3f89924f603..55d28c060784 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7111,7 +7111,29 @@  static int ftrace_process_locs(struct module *mod,
 
 	/* We should have used all pages unless we skipped some */
 	if (pg_unuse) {
-		WARN_ON(!skipped);
+		unsigned long pg_remaining, remaining;
+		unsigned long skip;
+
+		/* Count the number of entries unused and compare it to skipped. */
+		pg_remaining = (ENTRIES_PER_PAGE << pg->order) - pg->index;
+
+		if (!WARN(skipped < pg_remaining, "Extra allocated pages for ftrace")) {
+
+			skip = skipped - pg_remaining;
+
+			for (pg = pg_unuse; pg; pg = pg->next) {
+				remaining += 1 << pg->order;
+			}
+
+			skip = DIV_ROUND_UP(skip, ENTRIES_PER_PAGE);
+
+			/*
+			 * Check to see if the number of pages remaining would
+			 * just fit the number of entries skipped.
+			 */
+			WARN(skip != remaining, "Extra allocated pages for ftrace: %lu with %lu skipped",
+			     remaining, skipped);
+		}
 		/* Need to synchronize with ftrace_location_range() */
 		synchronize_rcu();
 		ftrace_free_pages(pg_unuse);