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b=VJmIiWTA0SPyUd6NSFdCQFTKb6GeSYwPjILc5D1E8i7ClalIhZ9mdBAqtzS0SHYYU At3POUaIk2b3XJJmmlb19kMgI80FrM9kOY8UrTQuTHQe0p2cmad7gzZMCXbMDHBqqo Cq4rvbeMeBVC4cE8g4+V9vm0ZsVBfhPy9BnerRmI= Date: Tue, 17 Mar 2026 11:34:52 -0700 From: Andrew Morton To: Oleg Nesterov Cc: Deepanshu Kartikey , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH -mm v2] do_notify_parent: sanitize the valid_signal() checks Message-Id: <20260317113452.cede9a514dfed36a1cb0e5a9@linux-foundation.org> In-Reply-To: References: <20260316151956.563558-1-kartikey406@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (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: 78727A000C X-Rspamd-Server: rspam07 X-Stat-Signature: 4wwfgamn7cpxhr4bk1se14eeyntwoy5m X-Rspam-User: X-HE-Tag: 1773772494-665008 X-HE-Meta: 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 Qyrm1EXC DiGPfPtp+hkhaSDYzsGcTsm/6H6XnhYon9arYc/hVPFsJe9uvyXc0pjrzEhq7/I04knZ1PysNfDOIDxJKWcd0+rzeZ5r8f9lIvZlowtRD1hwmn1deyScMYGa5vtuOGbMh2ky/9b2SxKZI0Qqne4bhhPPgxrN3XYVJUGVwSgQoWgdKI0nES3y7gWZgcC6h9WVYvBX/994M4o7BMFjrbf2wCXka9Z27YrpEglpZCRCXneRqfkoTZRxcg7Fa8UoBzERgNeBL5Niu+TSa6woOslyuf+uCi5/lETmBmZula+6skxc+NmiSS3dSI/rfdBaF05hAhKPie/Ex/8BZbxcSZGuS8Sgb0szUpHi5k5NYXEBA3alaEg7EWULga9brqK5VSnPYKKEy Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 17 Mar 2026 14:58:18 +0100 Oleg Nesterov wrote: > Now that kernel_clone() checks valid_signal(args->exit_signal), the "sig" > argument of do_notify_parent() must always be valid or we have a bug. > > However, do_notify_parent() only checks that sig != -1 at the start, then > it does another valid_signal() check before __send_signal_locked(). > > This is confusing. Change do_notify_parent() to WARN and return early if > valid_signal(sig) is false. Sashiko has a question: https://sashiko.dev/#/patchset/abld-ilvMEZ7VgMw%40redhat.com