From: Christoph Hellwig <hch@lst.de>
To: Maurizio Lombardi <mlombard@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, kbusch@kernel.org, axboe@fb.com,
hch@lst.de
Subject: Re: [PATCH] nvme-tcp: fix memory leak when freeing a queue
Date: Tue, 9 Nov 2021 09:13:03 +0100 [thread overview]
Message-ID: <20211109081303.GC28785@lst.de> (raw)
In-Reply-To: <20211103110310.GE4840@raketa>
On Wed, Nov 03, 2021 at 12:03:10PM +0100, Maurizio Lombardi wrote:
> > >
> > > Thanks Maurizio,
> > >
> > > Why do we need to the pf_cache.va protection? nvme_tcp_free_queue
> > > is already protected against re-entry with the NVME_TCP_Q_ALLOCATED
> > > bit.
> > >
> >
> > It's not the re-entry what worried me, I thought that nvme_tcp_free_queue()
> > might be called before page_frag_alloc() had the chance to initialize the pf_cache, triggering
> > a NULL pointer dereference. I am doing some tests right now and it seems not to be
> > possible so maybe we can drop the "if".
>
> Oh wait, if nvme_tcp_setup_ctrl() fails it could call nvme_tcp_destroy_io_queues() and
> iI guess that in that case the pf_cache is not initialized, so the if(pf_cache.va) protection
> is necessary.
Sagi, does this look good to you now?
next prev parent reply other threads:[~2021-11-09 8:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-03 8:18 [PATCH] nvme-tcp: fix memory leak when freeing a queue Maurizio Lombardi
2021-11-03 9:23 ` Sagi Grimberg
2021-11-03 10:45 ` Maurizio Lombardi
2021-11-03 11:03 ` Maurizio Lombardi
2021-11-09 8:13 ` Christoph Hellwig [this message]
2021-11-09 15:37 ` John Meneghini
2021-11-09 15:54 ` Sagi Grimberg
2021-11-11 10:00 ` Christoph Hellwig
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