From: Keith Busch <kbusch@kernel.org>
To: Niklas Cassel <cassel@kernel.org>
Cc: Justin Tee <justin.tee@broadcom.com>,
Naresh Gottumukkala <nareshgottumukkala83@gmail.com>,
Paul Ely <paul.ely@broadcom.com>, Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <kch@nvidia.com>,
stable@vger.kernel.org,
syzbot+f58e57380a6083c4041d@syzkaller.appspotmail.com,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH] nvme-fc: fix double free of fabrics options when nvme_add_ctrl() fails
Date: Fri, 14 Aug 2026 10:30:27 -0600 [thread overview]
Message-ID: <an9Co6vHIqggWNIf@kbusch-mbp> (raw)
In-Reply-To: <20260814143833.1953415-2-cassel@kernel.org>
On Fri, Aug 14, 2026 at 04:38:34PM +0200, Niklas Cassel wrote:
> ctrl->ctrl.opts also stays valid for the whole teardown now. That is
> not the bug being fixed, but it removes some fragility around the old
> idiom: nvme_free_ctrl() calls nvme_auth_free() before ->free_ctrl(), and
> ctrl_max_dhchaps() dereferences ctrl->opts without a NULL check when
> ctrl->dhchap_ctxs is set, which nvme-fc permits since NVMF_ALLOWED_OPTS
> allows the dhchap options. The nvme sysfs attributes that dereference
> ctrl->opts, such as hostnqn and address, evaluate their is_visible()
> test once at device_add() time and stay readable until
> cdev_device_del().
The allocation that ctrl.opts points is freed in this error path, so any
access after that is a use-after-free that needs to be fixed. I think
setting opts to NULL is easier than the proxy locked list check.
next prev parent reply other threads:[~2026-08-14 16:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-14 14:38 [PATCH] nvme-fc: fix double free of fabrics options when nvme_add_ctrl() fails Niklas Cassel
2026-08-14 16:30 ` Keith Busch [this message]
-- strict thread matches above, loose matches on Subject: below --
2026-08-11 2:06 [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvmf_free_options syzbot
2026-08-11 12:53 ` [PATCH] nvme-fc: fix double free of fabrics options when nvme_add_ctrl() fails Rihyeon Kim
2026-08-11 13:10 ` Niklas Cassel
2026-08-12 10:55 ` Rihyeon Kim
2026-08-12 10:59 ` Rihyeon Kim
2026-08-12 14:26 ` Niklas Cassel
2026-08-12 14:30 ` Niklas Cassel
2026-08-11 15:29 ` Keith Busch
2026-08-12 10:55 ` Rihyeon Kim
2026-08-12 10:59 ` Rihyeon Kim
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