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b=vX5UrLSPnARMXIX/mQM4uvVK8eB3MjSMjjqX7C0qIf7l5+GlOdecSGatxLiVysej4 UiFvVcaKGLgtzPXekd868HrxInxdfvChWUWJ1uQg7G5aBmNOCYUAFTKXj5RpDsQiCC HXWEYedmXBXK+9QGKMUNHwqteybGaznIrdeox5kI= Date: Sun, 12 Apr 2026 10:59:34 -0700 From: Andrew Morton To: Zi Yan Cc: Lance Yang , lgs201920130244@gmail.com, david@kernel.org, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm: thp: Fix refcount leak in thpsize_create() error path Message-Id: <20260412105934.50892a9988df0403c209c886@linux-foundation.org> In-Reply-To: <75F536FE-6710-4AE7-B6DB-2997D846237E@nvidia.com> References: <20260411062152.2092967-1-lgs201920130244@gmail.com> <20260411142858.85496-1-lance.yang@linux.dev> <848180C7-F98C-44B2-AB1F-579BF9EEA28E@nvidia.com> <3e688ea1-05ba-4e75-9d92-2751ff6f3b7b@linux.dev> <75F536FE-6710-4AE7-B6DB-2997D846237E@nvidia.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 67CC12000A X-Stat-Signature: pb51wedcd4b5jhywbsta9xydmm7mpn8y X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1776016782-29007 X-HE-Meta: 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 bhDUViga GJROwqjtgAndhkkeUBP6+S7GkmtCIJU/Rpez/HUmj2qA8oBeRi25B2AzQjk+1uAa5Z/OaMMILPQy3Y89w4vEpqJiAnbIZ67+k7n0tc/gurE6jBZYD/M2lD8UN706lloWVcfTV5o2XIPW389OuaQ4dbvvala78Q/rNUxfKcnZHF9iG0SeuE7LZuAOS/Nrd9B5IX/4rjPmezYc9meGhNPHP9RzbU6/WEfIcx9Icf8iVMwTLtjXecx/vOBQ22OeI7T+P0kEQH7RR7lJs7MuidCPjB+OA2nj6jSCxDk+YEBF6pxVuOAt3O7MrwIgLYRaBMmdK8kjK Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, 12 Apr 2026 09:33:29 -0400 Zi Yan wrote: > > wording, especially: > > > > "resulting in a refcount leak and potentially leading to a use-after-free" > > > > The old code does skip the required kobject cleanup path, but is > > a UAF actually possible there? > > That is my question too. The original code might not cause any real issue. > > Guangshuo, let us know if we get it wrong. Thanks. Thanks, all. I queued this for testing and added a note that a changlog update is expected.