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From: Eric Biggers <ebiggers@kernel.org>
To: stable@vger.kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>, SeongJae Park <sj@kernel.org>,
	Seth Jenkins <sethjenkins@google.com>,
	Jann Horn <jannh@google.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Baoquan He <bhe@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
	Xuefeng Li <lixuefeng@loongson.cn>,
	Tiezhu Yang <yangtiezhu@loongson.cn>,
	Marco Elver <elver@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 5.15 03/20] panic: unset panic_on_warn inside panic()
Date: Tue, 24 Jan 2023 10:50:53 -0800	[thread overview]
Message-ID: <20230124185110.143857-4-ebiggers@kernel.org> (raw)
In-Reply-To: <20230124185110.143857-1-ebiggers@kernel.org>

From: Tiezhu Yang <yangtiezhu@loongson.cn>

commit 1a2383e8b84c0451fd9b1eec3b9aab16f30b597c upstream.

In the current code, the following three places need to unset
panic_on_warn before calling panic() to avoid recursive panics:

kernel/kcsan/report.c: print_report()
kernel/sched/core.c: __schedule_bug()
mm/kfence/report.c: kfence_report_error()

In order to avoid copy-pasting "panic_on_warn = 0" all over the places,
it is better to move it inside panic() and then remove it from the other
places.

Link: https://lkml.kernel.org/r/1644324666-15947-4-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 kernel/panic.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 5ee281b996f9e..5ed1ad06f9a34 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -208,6 +208,16 @@ void panic(const char *fmt, ...)
 	int old_cpu, this_cpu;
 	bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
 
+	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;
+	}
+
 	/*
 	 * Disable local interrupts. This will prevent panic_smp_self_stop
 	 * from deadlocking the first cpu that invokes the panic, since
@@ -616,16 +626,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 	if (regs)
 		show_regs(regs);
 
-	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;
+	if (panic_on_warn)
 		panic("panic_on_warn set ...\n");
-	}
 
 	if (!regs)
 		dump_stack();
-- 
2.39.1


  parent reply	other threads:[~2023-01-24 18:52 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 18:50 [PATCH 5.15 00/20] Backport oops_limit to 5.15 Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 01/20] sysctl: add a new register_sysctl_init() interface Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 02/20] kernel/panic: move panic sysctls to its own file Eric Biggers
2023-01-24 18:50 ` Eric Biggers [this message]
2023-01-24 18:50 ` [PATCH 5.15 04/20] ubsan: no need to unset panic_on_warn in ubsan_epilogue() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 05/20] kasan: no need to unset panic_on_warn in end_report() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 06/20] exit: Add and use make_task_dead Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 07/20] objtool: Add a missing comma to avoid string concatenation Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 08/20] hexagon: Fix function name in die() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 09/20] h8300: Fix build errors from do_exit() to make_task_dead() transition Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 10/20] csky: Fix function name in csky_alignment() and die() Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 11/20] ia64: make IA64_MCA_RECOVERY bool instead of tristate Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 12/20] panic: Separate sysctl logic from CONFIG_SMP Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 13/20] exit: Put an upper limit on how often we can oops Eric Biggers
2023-01-25 14:09   ` Harshit Mogalapalli
2023-01-25 18:44     ` Eric Biggers
2023-01-25 18:59       ` Harshit Mogalapalli
2023-01-24 18:51 ` [PATCH 5.15 14/20] exit: Expose "oops_count" to sysfs Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 15/20] exit: Allow oops_limit to be disabled Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 16/20] panic: Consolidate open-coded panic_on_warn checks Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 17/20] panic: Introduce warn_limit Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 18/20] panic: Expose "warn_count" to sysfs Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 19/20] docs: Fix path paste-o for /sys/kernel/warn_count Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 20/20] exit: Use READ_ONCE() for all oops/warn limit reads Eric Biggers
2023-01-27  2:08 ` [PATCH 5.15 00/20] Backport oops_limit to 5.15 Sasha Levin

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