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Mon, 21 Sep 2026 09:00:38 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id JExEHDbysGqjWgAAD6G6ig (envelope-from ); Mon, 21 Sep 2026 09:00:38 +0000 Message-ID: <0d816796-3641-4982-9b28-484b226021f5@suse.de> Date: Mon, 21 Sep 2026 11:00:38 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] nvmet-fcloop: fail LS request synchronously when remote port is gone To: Nguyen Ngoc Thang , Justin Tee , Naresh Gottumukkala , Paul Ely , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni Cc: Daniel Wagner , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, syzbot+77955102efac681ec73b@syzkaller.appspotmail.com References: <20260920163804.67858-1-ngocthang2710.1999@gmail.com> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20260920163804.67858-1-ngocthang2710.1999@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Level: X-Spam-Score: -2.80 X-Spam-Flag: NO X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_SEVEN(0.00)[11]; FREEMAIL_TO(0.00)[gmail.com,broadcom.com,lst.de,grimberg.me,nvidia.com]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[77955102efac681ec73b]; MID_RHS_MATCH_FROM(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[syzkaller.appspot.com:url,suse.de:email,suse.de:mid,imap1.dmz-prg2.suse.org:helo,appspotmail.com:email] On 9/20/26 6:38 PM, Nguyen Ngoc Thang wrote: > fcloop_t2h_ls_req() handles a missing remoteport by queueing the request > on tport->ls_list and completing it with -ECONNREFUSED from a work item. > > nvmet_fc_delete_assoc_work() sends the Disconnect Association LS this > way. When it runs during nvmet_fc_unregister_targetport(), the work is > queued after flush_workqueue() has started, so it is not waited for. > nvmet_fc_free_pending_reqs() then frees the still-pending lsop and the > late work item calls lsreq->done() on freed memory: > > BUG: KASAN: slab-use-after-free in fcloop_rport_lsrqst_work+0x242/0x2e0 > Workqueue: nvmet-wq fcloop_tport_lsrqst_work > Allocated by nvmet_fc_xmt_disconnect_assoc > Freed by nvmet_fc_free_pending_reqs > nvmet_fc_unregister_targetport > fcloop_delete_target_port > > Return -ECONNREFUSED directly instead. __nvmet_fc_send_ls_req() unwinds > and nvmet_fc_xmt_disconnect_assoc() frees the lsop, so no completion is > left outstanding. > > Reported-by: syzbot+77955102efac681ec73b@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=77955102efac681ec73b > Fixes: bbccbf791e6f ("nvmet-fc: free pending reqs on tgtport unregister") > Signed-off-by: Nguyen Ngoc Thang > --- > drivers/nvme/target/fcloop.c | 17 +++++++---------- > 1 file changed, 7 insertions(+), 10 deletions(-) > > diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c > index b63af3b643a6..9f9fb40f8a97 100644 > --- a/drivers/nvme/target/fcloop.c > +++ b/drivers/nvme/target/fcloop.c > @@ -456,21 +456,18 @@ fcloop_t2h_ls_req(struct nvmet_fc_target_port *targetport, void *hosthandle, > * 1:1 tgtport vs remoteport > */ > > + /* > + * Fail synchronously: an async completion can run after > + * nvmet_fc_unregister_targetport() has freed the pending lsreq. > + */ > + if (!tport->remoteport) > + return -ECONNREFUSED; > + > tls_req = kmem_cache_alloc(lsreq_cache, GFP_KERNEL); > if (!tls_req) > return -ENOMEM; > tls_req->lsreq = lsreq; > INIT_LIST_HEAD(&tls_req->ls_list); > - > - if (!tport->remoteport) { > - tls_req->status = -ECONNREFUSED; > - spin_lock(&tport->lock); > - list_add_tail(&tls_req->ls_list, &tport->ls_list); > - spin_unlock(&tport->lock); > - queue_work(nvmet_wq, &tport->ls_work); > - return ret; > - } > - > tls_req->status = 0; > ret = nvme_fc_rcv_ls_req(tport->remoteport, &tls_req->ls_rsp, > lsreq->rqstaddr, lsreq->rqstlen); Can you create a blktest for this? Otherwise look good. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich