From: Florian Westphal <fw@strlen.de>
To: Michal Hocko <mhocko@suse.com>
Cc: Florian Westphal <fw@strlen.de>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz,
akpm@linux-foundation.org, urezki@gmail.com,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
Martin Zaharinov <micron10@gmail.com>
Subject: Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC
Date: Mon, 26 Sep 2022 12:08:00 +0200 [thread overview]
Message-ID: <20220926100800.GB12777@breakpoint.cc> (raw)
In-Reply-To: <YzFxHlYoncuDl2fM@dhcp22.suse.cz>
Michal Hocko <mhocko@suse.com> wrote:
> + old_tbl = rht_dereference_rcu(ht->tbl, ht);
> + size = tbl->size;
> +
> + data = ERR_PTR(-EBUSY);
> +
> + if (rht_grow_above_75(ht, tbl))
> + size *= 2;
> + /* Do not schedule more than one rehash */
> + else if (old_tbl != tbl)
> + return data;
> +
> + data = ERR_PTR(-ENOMEM);
> +
> + rcu_read_unlock();
> + new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
> + rcu_read_lock();
I don't think this is going to work, there can be callers that
rely on rcu protected data structures getting free'd.
Also, network stack assumes synchronize_rcu() means that all
inflight packets have completed processing.
next prev parent reply other threads:[~2022-09-26 10:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 10:38 [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC Florian Westphal
2022-09-23 13:29 ` Michal Hocko
2022-09-23 13:35 ` Florian Westphal
2022-09-23 14:43 ` Uladzislau Rezki
2022-09-23 14:54 ` Florian Westphal
2022-09-23 15:10 ` Uladzislau Rezki
2022-09-26 15:03 ` Vlastimil Babka
2022-09-26 15:28 ` Sebastian Andrzej Siewior
2022-09-26 7:49 ` Michal Hocko
2022-09-26 7:56 ` Florian Westphal
2022-09-26 8:57 ` Michal Hocko
2022-09-26 9:30 ` Michal Hocko
2022-09-26 10:08 ` Florian Westphal [this message]
2022-09-26 12:02 ` Michal Hocko
2022-09-26 13:08 ` Florian Westphal
2022-09-26 13:38 ` Florian Westphal
2022-09-26 14:05 ` Michal Hocko
2022-09-26 14:20 ` Florian Westphal
2022-09-26 14:32 ` Michal Hocko
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