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Message-Id: <20200227193516.32566-5-keescook@chromium.org>
Date: Thu, 27 Feb 2020 11:35:14 -0800
From: Kees Cook <keescook@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Kees Cook <keescook@...omium.org>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Elena Petrova <lenaptr@...gle.com>,
Andrey Konovalov <andreyknvl@...gle.com>,
Alexander Potapenko <glider@...gle.com>,
Dan Carpenter <dan.carpenter@...cle.com>,
"Gustavo A. R. Silva" <gustavo@...eddedor.com>,
Arnd Bergmann <arnd@...db.de>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
kasan-dev@...glegroups.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com,
syzkaller@...glegroups.com
Subject: [PATCH v5 4/6] 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.
Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com
Signed-off-by: Kees Cook <keescook@...omium.org>
---
lib/ubsan.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/lib/ubsan.c b/lib/ubsan.c
index 7b9b58aee72c..429663eef6a7 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,
--
2.20.1
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