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b=2euoCv+bvYSLHd+iLJPBfCTR9dYqkea4DbbiwXBQVYQLiOOXMeNpbH+FHFjIvShcI B/LLYSsCbZUlnmXrTOtJwOuJGFW2FgQG3FBnbyE1N8HBqOwClX0+VtD1Hpjt6azDwQ 5FH5bUfl4KIXmED3ylS4at9EIfR9Ky6Nz3VS/utE= Date: Wed, 14 Jan 2026 19:23:36 -0800 From: Andrew Morton To: ranxiaokai627@163.com Cc: surenb@google.com, kent.overstreet@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ran.xiaokai@zte.com.cn Subject: Re: [PATCH v2] alloc_tag: fix rw permission issue when handling boot parameter Message-Id: <20260114192336.9d98f0330bfd6c8638762dd0@linux-foundation.org> In-Reply-To: <20260115031536.164254-1-ranxiaokai627@163.com> References: <20260115031536.164254-1-ranxiaokai627@163.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-Stat-Signature: 7w8bzr7ux83qyjy8wdp1de3grf8bx1ws X-Rspam-User: X-Rspamd-Queue-Id: D5AAA40014 X-Rspamd-Server: rspam08 X-HE-Tag: 1768447417-834606 X-HE-Meta: U2FsdGVkX19/m+pstH10gYjIAoZoqr1ExG6C5L81jvmAz7qRStlY6o4qjyB7VxwHiTKzTXqo/WfdC8CKU5BV8M4uGp728Ms87sMfAye1ZL+GGn09CWK2TJ2/oe7v0uvLjyNlQQh6cAQRbDYMAXF8qgA2RZKsOzc+/rw+ZH3r+Yy+EbBnMCFYh+HFx/soqFhn1p4p7cy58ae42pK0++iIZTenT0U+i35SrijxbEFfOCHXACMXqRMXahlz3oC15myLOWpbdofFulBJJ2gM4BGNCToM10VbG/LEBDTXTLHkh8b/xUWzei9AYt9rrlBaZY2J5DksoWZ3BjVE+rSmlBT3gQUCmCuCnshDAzRt3Ku+1qc43rt5y6dFIFz+O+Yd8UC16mLvPr1ZwimSKA7wt5ygTGq/IW6XZ82gdftt5pHnGbIHISL6IuID5G0XaANCL4hWOmfAnhPlB96rR+dq2WAbpIWiE8YjvjczKHUmezs3n6DSJb4bqTea3VoenzRCgbH32b+dKz94CMrcBmEp11UAYtcWKmDKf8h7EaNmbcUKrzN6bmpBZXht9DOiATS3kFkq0F6YHiN0418DyyoDbkekyK0TnBdINWTmV7z2h+ISZTEgq9bkmXcLLxmbR8iBui1DILVrYFgTZQiyofy/6UaWK95M6KQNHf36XOqHxVuKjLoi0yYTXY+J6Ze2a/PgO7QjTX/ZgJtEg0WnRPTMkuZIkO544/Jg66QnhdORvmpy8r6LT9IVkkqwTozEPswznbRVvCCzZU4Lo0KyzyATyhc9b76/PKPO5AkImdHCt1bRWIXRufsUINtvNRxU+Us6ktfpkDTNj7eFJucRI0H6533rAht+FY7tzou0L1Kh7tkpuHRTY9u9zXZ2het2NvXNTLdDHlWcfFgQthDUKJ3JGSElc+30Nax4UypUZCZp2vx+yii8QeZvwGNQr2aDTYpBAgx/5HRb95sZTAEh4h9P1+s kmWlRAiK c56WjEjOERq3X8QEVVx9LYnvPAuHdLr1PG7zZR9MycdOwdrPM51F6c9tmV9r/IP89R80cq4yx6pfflEba41Xhxfm8nCJ4WyCcfna/6vYa2DxhhccZN76VxZzPTHP3cuXYcNHYMPZcaHuFiRoJG/wQvlm5bbHedQi1ez2DTjOPMiPyMC+Av25e0oLmcZHzY4G8APimEN37cpjrxGq15Z3sDgl8uc2Z7vAkQfxgLC2K8j+HdHkBO8/U70U7Bo1a2OQyNX/GfTzIOpxmtA/21jUEPZI8Z/+1WpTxAYWsRtuuEKPUzHeHl5JswxOvfBHUlLCRrVGR0SNReN7fH+4rj4kFI4JpRvq1o8q/Ka99hdiQoYxScIw= 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 Thu, 15 Jan 2026 03:15:36 +0000 ranxiaokai627@163.com wrote: > From: Ran Xiaokai > > Boot parameters prefixed with "sysctl." are processed > during the final stage of system initialization via kernel_init()-> > do_sysctl_args(). When CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled, > the sysctl.vm.mem_profiling entry is not writable and will cause > a warning. This sounds strange. Why would setting a Kconfig debug thing disable alteration of a runtime control? Documentation/mm/allocation-profiling.rst provided no hint. > Before run_init_process(), system initialization executes in kernel > thread context. Use current->mm to distinguish sysctl writes during > do_sysctl_args() from user-space triggered ones. > > And when the proc_handler is from do_sysctl_args(), always return success > because the same value was already set by setup_early_mem_profiling() > and this eliminates a permission denied warning. > > Suggested-by: Suren Baghdasaryan > Acked-by: Suren Baghdasaryan > Signed-off-by: Ran Xiaokai Should we backport it?