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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Score: -5.51 X-Rspamd-Queue-Id: EB423219F1 X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Level: X-Rspamd-Action: no action X-Spamd-Result: default: False [-5.51 / 50.00]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; DWL_DNSWL_LOW(-1.00)[suse.de:dkim]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; TAGGED_RCPT(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_TO(0.00)[gmail.com,kernel.org]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:email,suse.de:mid,imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+] X-Spam-Flag: NO On 9/20/26 3:39 PM, Ming Lei wrote: > Hello, > > On Fri, Sep 18, 2026 at 12:29:22PM +0200, Christian Brauner wrote: >> Hi, >> [ .. ] >> The commit 7fc4da6a304b ("ublk: scan partition in async way") made >> partition scans run from a workqueue that holds disk->open_mutex while >> the server serves its reads and START_DEV returns before it's finished. >> >> Any server that treats START_DEV's return as a signal that the disk is >> ready and doesn't serve requests hangs every open() of /dev/ublkbN on >> uninterruptible on open_mutex. You can combine that with (1) and (2). > > START_DEV doesn't promise partitions scanning done when it is returned. > > nvme multipath has similar usage too. > Indeed, we hit the same issue with nvme. We got it fixed by commit 1f021341eef41e77a633186e9be5223de2ce5d48 ('nvme-multipath: defer partition scanning'), essentially suppress partition scan during probing, and move the partition scan to a work thread. That way probing can continue (even if partition scan is blocked), and a failed probe can correctly abort partition scanning. 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