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From: Tiezhu Yang <yangtiezhu@loongson.cn>
To: Baoquan He <bhe@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Marco Elver <elver@google.com>
Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 5/5] kfence: unset panic_on_warn before calling panic()
Date: Fri, 28 Jan 2022 19:42:25 +0800	[thread overview]
Message-ID: <1643370145-26831-6-git-send-email-yangtiezhu@loongson.cn> (raw)
In-Reply-To: <1643370145-26831-1-git-send-email-yangtiezhu@loongson.cn>

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

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 mm/kfence/report.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index f93a7b2..9d61a23 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -267,8 +267,16 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 
 	lockdep_on();
 
-	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");
+	}
 
 	/* We encountered a memory safety error, taint the kernel! */
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);
-- 
2.1.0


WARNING: multiple messages have this Message-ID (diff)
From: Tiezhu Yang <yangtiezhu@loongson.cn>
To: kexec@lists.infradead.org
Subject: [PATCH 5/5] kfence: unset panic_on_warn before calling panic()
Date: Fri, 28 Jan 2022 19:42:25 +0800	[thread overview]
Message-ID: <1643370145-26831-6-git-send-email-yangtiezhu@loongson.cn> (raw)
In-Reply-To: <1643370145-26831-1-git-send-email-yangtiezhu@loongson.cn>

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

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 mm/kfence/report.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index f93a7b2..9d61a23 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -267,8 +267,16 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 
 	lockdep_on();
 
-	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");
+	}
 
 	/* We encountered a memory safety error, taint the kernel! */
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);
-- 
2.1.0



  parent reply	other threads:[~2022-01-28 11:42 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-28 11:42 [PATCH 0/5] Update doc and fix some issues about kdump Tiezhu Yang
2022-01-28 11:42 ` Tiezhu Yang
2022-01-28 11:42 ` [PATCH 1/5] docs: kdump: update description about sysfs file system support Tiezhu Yang
2022-01-28 11:42   ` Tiezhu Yang
2022-01-30  2:10   ` Baoquan He
2022-01-30  2:10     ` Baoquan He
2022-01-28 11:42 ` [PATCH 2/5] docs: kdump: add scp sample to write out the dump file Tiezhu Yang
2022-01-28 11:42   ` Tiezhu Yang
2022-01-30  2:46   ` Baoquan He
2022-01-30  2:46     ` Baoquan He
2022-01-28 11:42 ` [PATCH 3/5] kcsan: unset panic_on_warn before calling panic() Tiezhu Yang
2022-01-28 11:42   ` Tiezhu Yang
2022-01-28 11:42 ` [PATCH 4/5] sched: " Tiezhu Yang
2022-01-28 11:42   ` Tiezhu Yang
2022-01-28 11:52   ` Marco Elver
2022-01-28 11:52     ` Marco Elver
2022-01-30  0:29     ` Tiezhu Yang
2022-01-30  0:29       ` Tiezhu Yang
2022-01-28 11:42 ` Tiezhu Yang [this message]
2022-01-28 11:42   ` [PATCH 5/5] kfence: " Tiezhu Yang

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