From 1d28c8d6d076efdec762026f7192c7cf251c66be Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Mon, 6 Apr 2020 20:12:38 -0700
Subject: [PATCH] ubsan: check panic_on_warn
Syzkaller expects kernel warnings to panic when the panic_on_warn sysctl
is set. More work is needed here to have UBSan reuse the WARN
infrastructure, but for now, just check the flag manually.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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: Dmitry Vyukov <dvyukov@google.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com
Link: http://lkml.kernel.org/r/20200227193516.32566-5-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/ubsan.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/lib/ubsan.c b/lib/ubsan.c
index 7b9b58aee72c9..429663eef6a7d 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -156,6 +156,17 @@ static void ubsan_epilogue(void)
"========================================\n");
current->in_ubsan--;
+
+ 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");
+ }
}
static void handle_overflow(struct overflow_data *data, void *lhs,
--
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