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([2601:647:6700:3390::c8d1]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-747afeab785sm11834510b3a.56.2025.06.04.11.45.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Jun 2025 11:45:29 -0700 (PDT) From: Kuniyuki Iwashima To: lee@kernel.org Cc: Rao.Shoaib@oracle.com, aleksandr.mikhalitsyn@canonical.com, axboe@kernel.dk, brauner@kernel.org, davem@davemloft.net, david.laight.linux@gmail.com, edumazet@google.com, horms@kernel.org, kuba@kernel.org, kuniyu@amazon.com, linux-kernel@vger.kernel.org, mhal@rbox.co, netdev@vger.kernel.org, pabeni@redhat.com, sashal@kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v6.1 05/27] af_unix: Replace BUG_ON() with WARN_ON_ONCE(). Date: Wed, 4 Jun 2025 11:45:17 -0700 Message-ID: <20250604184528.141251-1-kuni1840@gmail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250604134347.GH7758@google.com> References: <20250604134347.GH7758@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Lee Jones Date: Wed, 4 Jun 2025 14:43:47 +0100 > On Fri, 23 May 2025, David Laight wrote: > > > On Wed, 21 May 2025 16:27:04 +0100 > > Lee Jones wrote: > > > > > From: Kuniyuki Iwashima > > > > > > [ Upstream commit d0f6dc26346863e1f4a23117f5468614e54df064 ] > > > > > > This is a prep patch for the last patch in this series so that > > > checkpatch will not warn about BUG_ON(). > > > > Does any of this actually make any sense? > > Either the BUG_ON() should be just deleted because it can't happen > > (or doesn't matter) or there should be an error path. > > Blindly replacing with WARN_ON_ONCE() can't be right. > > > > The last change (repeated here) > > > if (u) { > > > - BUG_ON(!u->inflight); > > > - BUG_ON(list_empty(&u->link)); > > > + WARN_ON_ONCE(!u->inflight); > > > + WARN_ON_ONCE(list_empty(&u->link)); > > > > > > u->inflight--; > > > if (!u->inflight) > > is clearly just plain wrong. > > If 'inflight' is zero then 'decrementing' it to ~0 is just going > > to 'crash and burn' very badly not much later on. > > All of this gets removed in patch 20, so I fear the point is moot. Right, and u->inflight never gets 0 before the decrementing in the first place.