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[142.167.56.70]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7d09a195d7dsm1046378985a.78.2025.06.04.08.14.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Jun 2025 08:14:33 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1uMpp2-000000006MV-3s6s; Wed, 04 Jun 2025 12:14:32 -0300 Date: Wed, 4 Jun 2025 12:14:32 -0300 From: Jason Gunthorpe To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , John Hubbard , Peter Xu Subject: Re: [PATCH v1] mm/gup: remove (VM_)BUG_ONs Message-ID: <20250604151432.GC17991@ziepe.ca> References: <20250604140544.688711-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250604140544.688711-1-david@redhat.com> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 10F531C0019 X-Stat-Signature: 1kfjr4k8wzfzm8hoo73c1k54k9rq9cwt X-Rspam-User: X-HE-Tag: 1749050074-190088 X-HE-Meta: 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 laLCP7Sr ygvH8PsdngtX2CaZzdKXJQoD9a9awGcj5Yuj41yv8Zx9NBV4N2jQrwq///S9ztdxxbKEYlNrILYoeeJ6OLzSQ14CtfLPFUIPPbkxxhkhEu1xLrUus5Hh4rGwafrMTPk56WW5jtVmDjegNbumLflfC560nOlyWfwz2vQGt3OAIRi+9/X7WXm8Pw33Lr64uiHZKpUlJsgqtg+WuLyb6s91SzgRqL1Q4Esq0aWal3/ISShRxYjREmDAXQgLCnXu1Qbg6UgkgLOBFxKkqcsnhWLr++vYSWA6Io1u59npAFfiSGK8vPgZjIW48re5uxkxiw4l5obNgHhlbKJnabwI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jun 04, 2025 at 04:05:44PM +0200, David Hildenbrand wrote: > Especially once we hit one of the assertions in > sanity_check_pinned_pages(), observing follow-up assertions failing > in other code can give good clues about what went wrong, so use > VM_WARN_ON_ONCE instead. > > While at it, let's just convert all VM_BUG_ON to VM_WARN_ON_ONCE as > well. Add one comment for the pfn_valid() check. > > We have to introduce VM_WARN_ON_ONCE_VMA() to make that fly. I'm fine with this, but IMHO, using ON_ONCE is wasteful here. They have been BUG_ONs for ages, they really do never happen. If there was ever a case to justify not using ON_ONCE this is it.. Jason