From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Daniel Wang <wonderfly@google.com>
Cc: rostedt@goodmis.org, Petr Mladek <pmladek@suse.com>,
stable@vger.kernel.org, Alexander.Levin@microsoft.com,
akpm@linux-foundation.org, byungchul.park@lge.com,
dave.hansen@intel.com, hannes@cmpxchg.org, jack@suse.cz,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Mel Gorman <mgorman@suse.de>,
mhocko@kernel.org, pavel@ucw.cz,
penguin-kernel@i-love.sakura.ne.jp, peterz@infradead.org,
tj@kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz,
Cong Wang <xiyou.wangcong@gmail.com>,
Peter Feiner <pfeiner@google.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes"
Date: Thu, 4 Oct 2018 17:05:06 +0900 [thread overview]
Message-ID: <20181004080506.GB12879@jagdpanzerIV> (raw)
In-Reply-To: <20181004074442.GA12879@jagdpanzerIV>
On (10/04/18 16:44), Sergey Senozhatsky wrote:
> So... Just an idea. Can you try a very dirty hack? Forcibly increase
> oops_in_progress in panic() before console_flush_on_panic(), so 8250
> serial8250_console_write() will use spin_trylock_irqsave() and maybe
> avoid deadlock.
E.g. something like below?
[this is not a patch; just a theory]:
---
diff --git a/kernel/panic.c b/kernel/panic.c
index 8b2e002d52eb..188338a55d1c 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -233,7 +233,13 @@ void panic(const char *fmt, ...)
if (_crash_kexec_post_notifiers)
__crash_kexec(NULL);
+ /*
+ * Decrement oops_in_progress and let bust_spinlocks() to
+ * unblank_screen(), console_unblank() and wake_up_klogd()
+ */
bust_spinlocks(0);
+ /* Set oops_in_progress, so we can reenter serial console driver*/
+ bust_spinlocks(1);
/*
* We may have ended up stopping the CPU holding the lock (in
next prev parent reply other threads:[~2018-10-04 8:05 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 19:46 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes" Daniel Wang
2018-10-01 19:23 ` Steven Rostedt
2018-10-01 20:13 ` Pavel Machek
2018-10-01 20:21 ` Vlastimil Babka
2018-10-01 20:38 ` Daniel Wang
2018-10-01 20:29 ` Steven Rostedt
2018-10-01 20:37 ` Daniel Wang
2018-10-01 20:40 ` Sasha Levin
2018-10-02 8:42 ` Petr Mladek
2018-10-02 17:21 ` Daniel Wang
2018-10-03 0:15 ` Daniel Wang
2018-10-03 1:23 ` Steven Rostedt
2018-10-03 9:14 ` Petr Mladek
2018-10-03 17:16 ` Daniel Wang
2018-10-03 17:37 ` Steven Rostedt
2018-10-03 18:37 ` Daniel Wang
2018-10-03 23:37 ` Daniel Wang
2018-10-04 7:44 ` Sergey Senozhatsky
2018-10-04 8:05 ` Sergey Senozhatsky [this message]
2018-10-04 8:36 ` Petr Mladek
2018-10-04 8:55 ` Sergey Senozhatsky
2018-10-21 18:09 ` Daniel Wang
2018-10-22 9:32 ` Petr Mladek
2018-10-22 10:09 ` Sergey Senozhatsky
2018-11-01 16:05 ` Daniel Wang
2018-11-09 6:47 ` Sergey Senozhatsky
2018-12-12 1:16 ` Daniel Wang
2018-12-12 5:21 ` Sergey Senozhatsky
2018-12-12 6:08 ` Daniel Wang
2018-12-12 6:28 ` Sergey Senozhatsky
2018-12-12 6:48 ` Sasha Levin
2018-12-12 8:10 ` Sergey Senozhatsky
2018-12-12 13:36 ` Petr Mladek
2018-12-12 13:59 ` Sergey Senozhatsky
2018-12-12 17:43 ` Sasha Levin
2018-12-12 20:11 ` Daniel Wang
2018-12-12 21:43 ` Sasha Levin
2018-12-12 21:49 ` Daniel Wang
2018-12-12 21:52 ` Sasha Levin
2018-12-12 21:56 ` Daniel Wang
2018-12-13 0:40 ` Daniel Wang
2018-12-13 2:27 ` Sergey Senozhatsky
2018-12-13 2:39 ` Daniel Wang
2018-12-13 9:59 ` Petr Mladek
2018-12-13 14:29 ` Sasha Levin
2018-12-13 2:07 ` Sergey Senozhatsky
2018-12-28 0:16 ` Sergey Senozhatsky
2018-12-28 8:27 ` Greg KH
2018-12-28 22:03 ` Daniel Wang
2018-12-30 3:03 ` Sergey Senozhatsky
2018-10-04 7:49 ` Petr Mladek
2018-10-02 8:16 ` Sergey Senozhatsky
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