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bh=eVoHe7gki5cWDhouGnejYKP4ZymSrtyZjdYp0G0mgKs=; b=mWLcirb8e/jEqvmhJ5A9D8/csD GZZ6qmjoVb/dLSKXjivspzcuigXDctbMT0xjlSfuxYiNClIYJRz5tk4mOOh/tlTKRSoxpSCb10GEH qxpWb0wEa4LHrM62CK7RezooI1KocproXqycgvEfDhml8xak9raWOh7W36eU2O6VJcj9mqcL0TDt9 Vk6AWv+cSLHqbslgSgK23PX2aNc9yf55LiY3DxSs+6pN9qIMmAiTgMdSeEnxF74MOgXfqXVywu7lm xulB4lhrD0MDVF5NTWxLh+Gxg0ExHXWZlXw0Dsa9sSee5/3frZ+/pvlVLFFTUjlemnyLWuIodKEEM rrcABVHw==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1s48jT-00000009A5v-15iX; Tue, 07 May 2024 00:30:59 +0000 Date: Mon, 6 May 2024 17:30:59 -0700 From: Luis Chamberlain To: Andrew Morton Cc: ziy@nvidia.com, linux-mm@kvack.org, fstests@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, willy@infradead.org, hare@suse.de, john.g.garry@oracle.com, p.raghav@samsung.com, da.gomez@samsung.com Subject: Re: [PATCH 1/2] mm/huge_memory: skip invalid debugfs file entry for folio split Message-ID: References: <20240424225449.1498244-1-mcgrof@kernel.org> <20240424225449.1498244-2-mcgrof@kernel.org> <20240425140126.2a62a5ec686813ee7deea658@linux-foundation.org> <20240429092307.37bf51c79f70bad4922f6277@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240429092307.37bf51c79f70bad4922f6277@linux-foundation.org> X-Stat-Signature: 3uy64ko8d7a5tbqo8sdxobixjkhopouq X-Rspamd-Queue-Id: 3B0181C0004 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1715041863-74453 X-HE-Meta: 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 IGPHmJj3 lMFwBkwTsDFZ2GtGVHqAWE/kAvo0Cxs1uB6pdMxjfxRuz6A98cCEsPeoh1Y7sray3QzYSpeMZ4Gj4DMKwTBfaB/YqgEEitfrx5Ad7QH8XoZors7cmtHisD6S7kus43L0ZluuhcX1F85PBmUPPjHvqKVd9G9dMjsBajQmwGkt+HD051miRpte4OSOccAmQxNE8dG1x0f0mUu0nz2P3lBId0UmAdmKzUECeWpcbr8llFe9N8+4oSSbwwdKpTbYQTIzoVFTXCSSBgjLCvRYM74IHc+oQHufUDSGAijDDOIbfginS/C4S8RdOIYCh/hcHXR4O5LNQxsCKWanQozRCI1TeppLv4xB+5P4kSNC/6GCQGepTCw4GC3M+RjE8cA/gYewbRbrfxyfE/HqREe3YbXkAX9Jk+72k0+FPDIwa 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 Mon, Apr 29, 2024 at 09:23:07AM -0700, Andrew Morton wrote: > On Sun, 28 Apr 2024 21:04:50 -0700 Luis Chamberlain wrote: > > > On Thu, Apr 25, 2024 at 02:01:26PM -0700, Andrew Morton wrote: > > > On Wed, 24 Apr 2024 15:54:48 -0700 Luis Chamberlain wrote: > > > > > > > If the file entry is too long we may easily end up going out of bounds > > > > and crash after strsep() on sscanf(). > > > > > > > > > > Can you explain why? I'm not seeing it. > > > > I couldn't see it either but I just looked at the crash below and > > its the only thing I could think of. So I think its when userspace > > somehow abuses MAX_INPUT_BUF_SZ a lot somehow. > > This isn't a good basis for making kernel changes :( > > Can you investigate a little further please? Sure, this will require some more time, feel free to ignore these two patches for now then. Luis