From: Thomas Graf <tgraf@suug.ch>
To: Ying Xue <ying.xue@windriver.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>, netdev@vger.kernel.org
Subject: Re: rhashtable: Fix potential crash on destroy in rhashtable_shrink
Date: Mon, 2 Feb 2015 09:48:19 +0000 [thread overview]
Message-ID: <20150202094819.GA22611@casper.infradead.org> (raw)
In-Reply-To: <54CF44B0.4040205@windriver.com>
On 02/02/15 at 05:34pm, Ying Xue wrote:
> On 01/31/2015 05:36 PM, Herbert Xu wrote:
> > The current being_destroyed check in rhashtable_expand is not
> > enough since if we start a shrinking process after freeing all
> > elements in the table that's also going to crash.
> >
>
> Sorry, I cannot understand the scenario.
>
> When we free the table in rhashtable_destroy(), we call
> cancel_work_sync() to synchronously cancel the work. So, why does your
> described crash still happen?
It's nft_hash specific. nft_hash frees all entries under ht->mutex without
unlinking them upon destroy and sets being_destroyed before doing. Therefore
it must be ensured that a resize is not started afterwards because the table
contains freed entries.
next prev parent reply other threads:[~2015-02-02 9:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-31 9:36 rhashtable: Fix potential crash on destroy in rhashtable_shrink Herbert Xu
2015-01-31 11:16 ` Thomas Graf
2015-01-31 11:22 ` Herbert Xu
2015-01-31 12:15 ` Thomas Graf
2015-02-02 9:34 ` Ying Xue
2015-02-02 9:48 ` Thomas Graf [this message]
2015-02-03 3:19 ` David Miller
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