lkml.org 
[lkml]   [2023]   [Feb]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.19 02/16] panic: unset panic_on_warn inside panic()
Date
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 8138a676fb7d1..a078d413042f2 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -142,6 +142,16 @@ 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
@@ -530,16 +540,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
if (args)
vprintk(args->fmt, args->args);

- 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");
- }

print_modules();

--
2.39.1
\
 
 \ /
  Last update: 2023-03-27 00:06    [W:0.095 / U:0.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site