From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Byungchul Park <byungchul.park@lge.com>,
akpm@linux-foundation.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, akinobu.mita@gmail.com,
jack@suse.cz, torvalds@linux-foundation.org
Subject: Re: [PATCH v4] lib/spinlock_debug.c: prevent a recursive cycle in the debug code
Date: Fri, 29 Jan 2016 15:37:24 +0900 [thread overview]
Message-ID: <20160129063656.GF4820@swordfish> (raw)
In-Reply-To: <20160129061653.GE4820@swordfish>
On (01/29/16 15:16), Sergey Senozhatsky wrote:
>
> http://marc.info/?l=linux-kernel&m=144976121529901
>
hm... I don't like that patch. ->reset() loop must be done outside
of zap_locks(). we can have a printk() recursion in CPU1, but console
driver lock may be owned by CPU2 in driver's handle_IRQ(), for example.
stealing its lock CPU1 is not really good. in my kernels I do this from
panic() path only, where I know that things are already bad.
panic()->console_panic_mode()->{for_each_console()->reset(), zap_locks()}->console_trelock()->console_unlock().
-ss
next prev parent reply other threads:[~2016-01-29 6:36 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-27 12:01 [PATCH v4] lib/spinlock_debug.c: prevent a recursive cycle in the debug code Byungchul Park
2016-01-27 22:49 ` Peter Hurley
2016-01-28 7:15 ` Byungchul Park
2016-01-29 8:19 ` Byungchul Park
2016-01-28 1:42 ` Byungchul Park
2016-01-28 2:37 ` Sergey Senozhatsky
2016-01-28 4:36 ` byungchul.park
2016-01-28 6:05 ` Sergey Senozhatsky
2016-01-28 8:13 ` Byungchul Park
2016-01-28 10:41 ` Sergey Senozhatsky
2016-01-28 10:53 ` Sergey Senozhatsky
2016-01-28 15:42 ` Sergey Senozhatsky
2016-01-28 23:08 ` Peter Hurley
2016-01-28 23:54 ` Byungchul Park
2016-01-29 0:54 ` Sergey Senozhatsky
2016-01-29 3:00 ` Byungchul Park
2016-01-29 4:05 ` Sergey Senozhatsky
2016-01-29 12:15 ` Byungchul Park
2016-01-29 0:27 ` Sergey Senozhatsky
2016-01-29 4:32 ` Peter Hurley
2016-01-29 5:28 ` Sergey Senozhatsky
2016-01-29 5:48 ` Peter Hurley
2016-01-29 6:16 ` Sergey Senozhatsky
2016-01-29 6:37 ` Sergey Senozhatsky [this message]
2016-01-31 12:30 ` Sergey Senozhatsky
2016-01-31 12:33 ` [PATCH 1/3] printk: introduce console_reset_on_panic() function Sergey Senozhatsky
2016-01-31 12:33 ` [PATCH 2/3] printk: introduce reset_console_drivers() Sergey Senozhatsky
2016-01-31 12:47 ` kbuild test robot
2016-01-31 12:33 ` [PATCH 3/3] spinlock_debug: panic on recursive lock spin_dump() Sergey Senozhatsky
2016-02-01 16:14 ` Sergey Senozhatsky
2016-02-02 7:59 ` Sergey Senozhatsky
2016-01-31 12:42 ` [PATCH 1/3] printk: introduce console_reset_on_panic() function kbuild test robot
2016-01-29 6:54 ` [PATCH v4] lib/spinlock_debug.c: prevent a recursive cycle in the debug code Byungchul Park
2016-01-29 7:13 ` Sergey Senozhatsky
2016-01-29 8:13 ` Byungchul Park
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