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From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Elena Petrova <lenaptr@google.com>,
	Alexander Potapenko <glider@google.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com, syzkaller@googlegroups.com
Subject: [PATCH v3 5/6] kasan: Unset panic_on_warn before calling panic()
Date: Wed, 15 Jan 2020 17:23:20 -0800	[thread overview]
Message-ID: <20200116012321.26254-6-keescook@chromium.org> (raw)
In-Reply-To: <20200116012321.26254-1-keescook@chromium.org>

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

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 mm/kasan/report.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 621782100eaa..844554e78893 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -92,8 +92,16 @@ static void end_report(unsigned long *flags)
 	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();
 }
 
-- 
2.20.1


  parent reply	other threads:[~2020-01-16  1:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16  1:23 [PATCH v3 0/6] ubsan: Split out bounds checker Kees Cook
2020-01-16  1:23 ` [PATCH v3 1/6] ubsan: Add trap instrumentation option Kees Cook
2020-01-16  1:23 ` [PATCH v3 2/6] ubsan: Split "bounds" checker from other options Kees Cook
2020-01-16  1:23 ` [PATCH v3 3/6] lkdtm/bugs: Add arithmetic overflow and array bounds checks Kees Cook
2020-01-16  1:23 ` [PATCH v3 4/6] ubsan: Check panic_on_warn Kees Cook
2020-01-16  1:23 ` Kees Cook [this message]
2020-01-16  5:23   ` [PATCH v3 5/6] kasan: Unset panic_on_warn before calling panic() Dmitry Vyukov
2020-01-16 23:49     ` Kees Cook
2020-01-17  9:54       ` Dmitry Vyukov
2020-01-17 21:20         ` Kees Cook
2020-01-18  9:19           ` Dmitry Vyukov
2020-01-16  1:23 ` [PATCH v3 6/6] ubsan: Include bug type in report header Kees Cook
2020-01-16 12:32   ` Andrey Konovalov

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