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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-93c248223dbsm499338585a.10.2026.09.24.09.28.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Sep 2026 09:28:41 -0700 (PDT) Date: Thu, 24 Sep 2026 12:28:39 -0400 From: Gregory Price To: "Lorenzo Stoakes (ARM)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v3 01/40] mm/vma: fix mmap_prepare file handling, remove file_doesnt_need_get Message-ID: References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-1-4583d8a23bca@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-1-4583d8a23bca@kernel.org> X-Rspam-User: X-Stat-Signature: coz8q6jqe1ifyyprmpugnxfim3sc519q X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 1454280009 X-HE-Tag: 1790267322-708154 X-HE-Meta: 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 tLG0L+gS VrhGHxsCUDunFTrn/K+cGT2Sidp7gEpMIKCAtXZq3CKbfp2b3SayWPa1debDBLBy8I5O+gKZlWjzoK10m8tALUHQud1VzYaTNd5dUVQjW1QLPcCanDMEg+TUoKqV8rnXfLd7UCFYQGpelND039IBeenjfCumdyQsVnK0SzU3QtBHfWh2oUxRl+XCMb/+EZkzWZXHWsB+QkqzZ6hsisLgPuhv+s2Sx+xh91JiT0hhFpmqfoii091rvsTg3VRUfmpj2W8CQKwP8B+MlcM2UWAGp4qLsiu3GT21IJjHeHRzYhpWeHDM37sxAo5JOlniaAdXmhOpKKoGwqX14mtyGEt6Pue0IdexzY/E/VQqepRxcyZl9iCj/8J02BmOaVg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 17, 2026 at 05:22:10PM +0100, Lorenzo Stoakes (ARM) wrote: > +static void put_map(struct mmap_state *map) > +{ ... > + if (map->vm_file && !map_same_file(map)) > + fput(map->vm_file); ... > diff --git a/mm/vma.h b/mm/vma.h > index e97bd2dfa786..f15faa83f3d6 100644 > --- a/mm/vma.h > +++ b/mm/vma.h > @@ -394,8 +394,10 @@ static inline void compat_set_vma_from_desc(struct vm_area_struct *vma, > > + if (desc->vm_file != vma->vm_file) { > + fput(vma->vm_file); Sashiko pointed out that this could be null if the vma is "anonymized". Previously we'd discussed that anonymizing a file folio is more of a wart than a feature, and IIRC you intended to remove that (i think?) when you removed zero-file mapping "anonymization" so some of this VMA stuff could be detangled. If this is an intermediate state, do we still need to manage this NULL scenario, and when we drop the anonymization mechanism we add a WARN() that says someone is being naughty? ~Gregory