linux-kernel - [PATCH v3 5/6] ftrace: Update the mcount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250213162146.158076547@goodmis.org>
Date: Thu, 13 Feb 2025 11:20:52 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org,
 linux-trace-kernel@...r.kernel.org,
 linux-kbuild@...r.kernel.org,
 bpf <bpf@...r.kernel.org>,
 linux-arm-kernel@...ts.infradead.org,
 linux-s390@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
 Mark Rutland <mark.rutland@....com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Peter Zijlstra <peterz@...radead.org>,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 Masahiro Yamada <masahiroy@...nel.org>,
 Nathan Chancellor <nathan@...nel.org>,
 Nicolas Schier <nicolas@...sle.eu>,
 Zheng Yejian <zhengyejian1@...wei.com>,
 Martin  Kelly <martin.kelly@...wdstrike.com>,
 Christophe Leroy <christophe.leroy@...roup.eu>,
 Josh Poimboeuf <jpoimboe@...hat.com>,
 Heiko Carstens <hca@...ux.ibm.com>,
 Catalin Marinas <catalin.marinas@....com>,
 Will Deacon <will@...nel.org>,
 Vasily Gorbik <gor@...ux.ibm.com>,
 Alexander Gordeev <agordeev@...ux.ibm.com>
Subject: [PATCH v3 5/6] ftrace: Update the mcount_loc check of skipped entries

From: Steven Rostedt <rostedt@...dmis.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@...dmis.org>
---
 kernel/trace/ftrace.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

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);
-- 
2.47.2