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[34.85.134.180]) by smtp.gmail.com with UTF8SMTPSA id 00721157ae682-79b10c64964sm18223897b3.7.2026.03.26.13.46.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2026 13:46:04 -0700 (PDT) Date: Thu, 26 Mar 2026 16:46:04 -0400 From: Willem de Bruijn To: Jakub Kicinski , Willem de Bruijn Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, Yiming Qian , daniel.zahka@gmail.com Message-ID: In-Reply-To: <20260326130459.7225ae28@kernel.org> References: <20260324205107.318303-1-kuba@kernel.org> <20260326130459.7225ae28@kernel.org> Subject: Re: [PATCH net] net: psp: check for device unregister when creating assoc Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Jakub Kicinski wrote: > On Tue, 24 Mar 2026 18:40:00 -0400 Willem de Bruijn wrote: > > > @@ -320,6 +320,11 @@ int psp_assoc_device_get_locked(const struct genl_split_ops *ops, > > > id = info->attrs[PSP_A_ASSOC_DEV_ID]; > > > if (psd) { > > > mutex_lock(&psd->lock); > > > + if (!psp_dev_is_registered(psd)) { > > > + mutex_unlock(&psd->lock); > > > + err = -ENODEV; > > > + goto err_psd_put; > > > + } > > > > This ensures that psd is valid for this caller of psp_dev_get_for_sock > > and psp_dev_tryget, which is its only one (for now). > > > > But is it confusing that psd can be cleared out while a reference is > > held? Is the assumption that psp_dev_unregister usually holds the last > > reference and its psp_dev_put will complete the clean up by calling > > psp_dev_free. If so, would it make sense to defer everything > > to psp_dev_free? > > > > This is a simpler changes and fixes the issue for the only caller, so > > LGTM. Just curious. > > Meaning we should add a dance around removal like netdev does? > Sleep until all the references are gone? > Subjectively I think it's ugly, and in netdev it didn't really > prevent races. Dunno, definitely subjective. Yeah, if any caller of psp_dev_unregister has to know that the device is gone to proceed, it would require something like that. Okay, I see that that is needlessly messy.