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Mon, 11 May 2026 09:47:31 +0000 Message-ID: Date: Mon, 11 May 2026 11:47:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V4 3/9] nvme: fix race condition between connected uevent and STARTED_ONCE flag To: Maurizio Lombardi , kbusch@kernel.org Cc: mheyne@amazon.de, emilne@redhat.com, jmeneghi@redhat.com, linux-nvme@lists.infradead.org, dwagner@suse.de, mlombard@arkamax.eu, mkhalfella@purestorage.com, chaitanyak@nvidia.com, hare@kernel.org, hch@lst.de References: <20260508133335.98612-1-mlombard@redhat.com> <20260508133335.98612-4-mlombard@redhat.com> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20260508133335.98612-4-mlombard@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Action: no action X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; DWL_DNSWL_BLOCKED(0.00)[suse.de:dkim]; FUZZY_RATELIMITED(0.00)[rspamd.com]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_TWELVE(0.00)[12]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:dkim,suse.de:mid,imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:104:10:150:64:97:from,2a07:de40:b281:106:10:150:64:167:received]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 41F6168566 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260511_024733_445719_362C2418 X-CRM114-Status: GOOD ( 16.52 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 5/8/26 15:33, Maurizio Lombardi wrote: > When a controller connects, nvme_start_ctrl() emits the > "NVME_EVENT=connected" uevent and sets the NVME_CTRL_STARTED_ONCE flag. > Currently, the uevent is emitted before the flag is set. > > This creates a race condition for userspace tools (like udev rules) > that might rely on the "connected" event to configure sysfs attributes. > Specifically, if a udev rule attempts to set the newly introduced > `admin_timeout` attribute immediately after receiving the uevent, > the sysfs store function might evaluate the NVME_CTRL_STARTED_ONCE > bit before it is actually set, resulting in spurious -EBUSY error. > > Swap the order of operations in nvme_start_ctrl() so that the > NVME_CTRL_STARTED_ONCE flag is set before the uevent is sent. > This guarantees that the admin_timeout can already be changed > when userspace is notified. > > Signed-off-by: Maurizio Lombardi > --- > drivers/nvme/host/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index b1bfcd0a0e5b..22be8cf5e982 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -5039,8 +5039,8 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl) > nvme_mpath_update(ctrl); > } > > - nvme_change_uevent(ctrl, "NVME_EVENT=connected"); > set_bit(NVME_CTRL_STARTED_ONCE, &ctrl->flags); > + nvme_change_uevent(ctrl, "NVME_EVENT=connected"); > } > EXPORT_SYMBOL_GPL(nvme_start_ctrl); > Reviewed-by: Hannes Reinecke 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