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d=linux-foundation.org; s=korg; t=1694381189; bh=a33KfcWJuQGo7k3UmN/sX7vPvQjyF64qX/+x3+bVGlk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=dW46YccVrszgrK7dBtj1+T49aiYMkU43M/tcSJ9AF+Vkj1lyD69Oqm/kd72YYYUkc Eex+gVGfawd1vjprWPmV/L+c7krku458Ro3RXGmS4c0oC9o5RYqX/LnhTdAhbfbySJ sY1nP8NjW7NTm5QElsSitBNSYs92+QrP0VSwJVEk= Date: Sun, 10 Sep 2023 14:26:27 -0700 From: Andrew Morton To: Xiu Jianfeng Cc: Liam.Howlett@oracle.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, xiujianfeng@huawei.com Subject: Re: [PATCH] mm: remove duplicated vma->vm_flags check when expanding stack Message-Id: <20230910142627.0dce42578bfaab7c4c67e316@linux-foundation.org> In-Reply-To: <20230906103312.645712-1-xiujianfeng@huaweicloud.com> References: <20230906103312.645712-1-xiujianfeng@huaweicloud.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-Server: rspam09 X-Rspamd-Queue-Id: 85F0E80009 X-Stat-Signature: 3zmaugkzp5k8h8ssb8xo5jc7djdr4fg4 X-Rspam-User: X-HE-Tag: 1694381195-353086 X-HE-Meta: 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 y1DH6yA3 nyJ8DbjtL0vysNh1ZyVBII8RPCiDo80CQuQJ/+8lujG5qYmDE/0bqapdok2Zb3kW6ClUTg7T4v6gtHx5MaDhX77fVmOZ1gySm8elhToEyGCRDCX6WKNvlkZm4cPzJOIE65hJnA6TMQcsAwzmRN49EDtazdmUyOU9eL47KuFxD2v4b4Hpt8CSS31q8dn8GLZQLqkKh/MsHO6+rW8BSu9IDeDHm4lQy5B3CgGS23WRyCGO9P6YMu88N9bXbdx0Jid8huCFEQ5v3I3WnMry9UC0OWiMjz01RliaIRl/zkk5xNoMkhccuznsYS235edzeEyFaGFke7IKc0w/qYkVMZ1BxzQjsdqRWe1EPM0/CwhVisgu2L7r654jNzB8wR5GBKPlvoFToPFEDBXSBcyORM8+ozQiYkuLylYD7GhfMAc6vpp7Fqu7zUhfPr8T6AVThpJPNWKLsaRPJxAXF6/4= 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: On Wed, 6 Sep 2023 10:33:12 +0000 Xiu Jianfeng wrote: > expand_upwards() and expand_downwards() will return -EFAULT if VM_GROWSUP > or VM_GROWSDOWN is not correctly set in vma->vm_flags, however in > !CONFIG_STACK_GROWSUP case, expand_stack_locked() returns -EINVAL first > if !(vma->vm_flags & VM_GROWSDOWN) before calling expand_downwards(), to > keep the consistency with CONFIG_STACK_GROWSUP case, remove this check. What are the user-visible effects of this change? Do you believe this fix should be backported into earlier kernel versions?