From: Keith Busch <kbusch@kernel.org>
To: Maurizio Lombardi <mlombard@redhat.com>
Cc: hch@lst.de, linux-nvme@lists.infradead.org, dwagner@suse.de,
mlombard@arkamax.eu
Subject: Re: [PATCH RFC] nvme: fix crash due to invalid cdev teardown
Date: Thu, 4 Jun 2026 22:33:42 +0100 [thread overview]
Message-ID: <aiHvNvqHTprJmzRO@kbusch-mbp> (raw)
In-Reply-To: <20260604134308.192478-1-mlombard@redhat.com>
On Thu, Jun 04, 2026 at 03:43:08PM +0200, Maurizio Lombardi wrote:
> In the NVMe multipath code, if nvme_add_ns_head_cdev() fails during
> nvme_mpath_set_live(), the error is completely ignored. However, during
> teardown, nvme_remove_head() unconditionally calls nvme_cdev_del().
> This teardown asymmetry leads to a kernel panic if the character device
> was never successfully initialized, which might happen in very rare
> circumstances.
Yeah, we need symmetry here, so no argument on that. Your patch is a bit
odd, though, in that you're treating multipath cdev failure differently
than non-multipath. I honestly hadn't considered this extremely unlikely
scenario. I guess we should proceed with just the gendisk in all cases,
but I know of several important uses that definitely need the generic
cdev handle here, so I think we need a clear error message that this
error event happened.
prev parent reply other threads:[~2026-06-04 21:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 13:43 [PATCH RFC] nvme: fix crash due to invalid cdev teardown Maurizio Lombardi
2026-06-04 13:51 ` Maurizio Lombardi
2026-06-04 21:33 ` Keith Busch [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aiHvNvqHTprJmzRO@kbusch-mbp \
--to=kbusch@kernel.org \
--cc=dwagner@suse.de \
--cc=hch@lst.de \
--cc=linux-nvme@lists.infradead.org \
--cc=mlombard@arkamax.eu \
--cc=mlombard@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox