diff mbox series

[162/166] kasan: unset panic_on_warn before calling panic()

Message ID 20200407031242.brxg9O47-%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/166] mm, memcg: bypass high reclaim iteration for cgroup hierarchy root | expand

Commit Message

Andrew Morton April 7, 2020, 3:12 a.m. UTC 
From: Kees Cook <keescook@chromium.org>
Subject: kasan: unset panic_on_warn before calling panic()

As done in the full WARN() handler, panic_on_warn needs to be cleared
before calling panic() to avoid recursive panics.

Link: http://lkml.kernel.org/r/20200227193516.32566-6-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kasan/report.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/mm/kasan/report.c~kasan-unset-panic_on_warn-before-calling-panic
+++ a/mm/kasan/report.c
@@ -92,8 +92,16 @@  static void end_report(unsigned long *fl
 	pr_err("==================================================================\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irqrestore(&report_lock, *flags);
-	if (panic_on_warn)
+	if (panic_on_warn) {
+		/*
+		 * This thread may hit another WARN() in the panic path.
+		 * Resetting this prevents additional WARN() from panicking the
+		 * system on this thread.  Other threads are blocked by the
+		 * panic_mutex in panic().
+		 */
+		panic_on_warn = 0;
 		panic("panic_on_warn set ...\n");
+	}
 	kasan_enable_current();
 }