From: Qian Cai <cai@lca.pw>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: mhocko@kernel.org, sergey.senozhatsky.work@gmail.com,
pmladek@suse.com, rostedt@goodmis.org, peterz@infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/page_isolation: fix a deadlock with printk()
Date: Sat, 5 Oct 2019 21:56:11 -0400 [thread overview]
Message-ID: <C0978EE1-42D7-4D62-BB9E-6CF5F2BEF3AF@lca.pw> (raw)
In-Reply-To: <20191005174423.23f2db80872a9365009f398a@linux-foundation.org>
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> On Oct 5, 2019, at 8:44 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> "ease" isn't the main objective. A more important question is "what
> makes sense". We should be able to call printk() from anywhere, any
> time under any conditions. That can't be done 100% but it is the
> objective. printk() should be robust and not being able to call
> printk() while holding zone->lock isn't robust!
https://github.com/torvalds/linux/commit/dbdda842fe96f8932bae554f0adf463c27c42bc7
If you look at the above commit, it explicitly call out the possible deadlock scenarios and recommend to call printk_deferred() instead in those areas of code where zone->lock looks like one of those candidates.
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next prev parent reply other threads:[~2019-10-06 1:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 16:42 Qian Cai
2019-10-04 17:47 ` David Hildenbrand
2019-10-04 18:53 ` Qian Cai
2019-10-05 23:29 ` Andrew Morton
2019-10-06 0:10 ` Qian Cai
2019-10-06 0:44 ` Andrew Morton
2019-10-06 1:10 ` Qian Cai
2019-10-06 1:56 ` Qian Cai [this message]
2019-10-06 0:59 ` Qian Cai
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