From: Christoph Hellwig <hch@infradead.org>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile
Date: Sat, 11 Jul 2015 03:02:32 -0700 [thread overview]
Message-ID: <20150711100232.GA4607@infradead.org> (raw)
In-Reply-To: <1436583115-6323-1-git-send-email-sergey.senozhatsky@gmail.com>
On Sat, Jul 11, 2015 at 11:51:53AM +0900, Sergey Senozhatsky wrote:
> Hello,
>
> Shrinker API does not handle nicely unregister_shrinker() on a not-registered
> ->shrinker. Looking at shrinker users, they all have to
> (a) carry on some sort of a flag to make sure that "unregister_shrinker()"
> will not blow up later
> (b) be fishy (potentially can Oops)
> (c) access private members `struct shrinker' (e.g. `shrink.list.next')
Ayone who does that is broken. You just need to have clear init (with
proper unwinding) and exit functions and order things properly. It
works like most register/unregister calls and should stay that way.
Maye you you should ty to explain what practical problem you're seeing
to start with.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile
Date: Sat, 11 Jul 2015 03:02:32 -0700 [thread overview]
Message-ID: <20150711100232.GA4607@infradead.org> (raw)
In-Reply-To: <1436583115-6323-1-git-send-email-sergey.senozhatsky@gmail.com>
On Sat, Jul 11, 2015 at 11:51:53AM +0900, Sergey Senozhatsky wrote:
> Hello,
>
> Shrinker API does not handle nicely unregister_shrinker() on a not-registered
> ->shrinker. Looking at shrinker users, they all have to
> (a) carry on some sort of a flag to make sure that "unregister_shrinker()"
> will not blow up later
> (b) be fishy (potentially can Oops)
> (c) access private members `struct shrinker' (e.g. `shrink.list.next')
Ayone who does that is broken. You just need to have clear init (with
proper unwinding) and exit functions and order things properly. It
works like most register/unregister calls and should stay that way.
Maye you you should ty to explain what practical problem you're seeing
to start with.
next prev parent reply other threads:[~2015-07-11 10:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-11 2:51 [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile Sergey Senozhatsky
2015-07-11 2:51 ` Sergey Senozhatsky
2015-07-11 2:51 ` [PATCH 1/2] mm/shrinker: do not NULL dereference uninitialized shrinker Sergey Senozhatsky
2015-07-11 2:51 ` Sergey Senozhatsky
2015-07-11 2:51 ` [PATCH 2/2] mm/shrinker: add init_shrinker() function Sergey Senozhatsky
2015-07-11 2:51 ` Sergey Senozhatsky
2015-07-11 10:02 ` Christoph Hellwig [this message]
2015-07-11 10:02 ` [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile Christoph Hellwig
2015-07-12 2:47 ` Sergey Senozhatsky
2015-07-12 2:47 ` Sergey Senozhatsky
2015-07-13 6:33 ` Christoph Hellwig
2015-07-13 6:33 ` Christoph Hellwig
2015-07-13 6:52 ` Sergey Senozhatsky
2015-07-13 6:52 ` Sergey Senozhatsky
2015-07-13 9:03 ` Christoph Hellwig
2015-07-13 9:03 ` Christoph Hellwig
2015-07-13 9:34 ` Sergey Senozhatsky
2015-07-13 9:34 ` Sergey Senozhatsky
2015-07-14 7:17 ` Christoph Hellwig
2015-07-14 7:17 ` Christoph Hellwig
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