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Tue, 18 Feb 2025 01:11:58 -0800 (PST) Received: from [192.168.0.24] ([82.76.24.202]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5e076048c05sm924724a12.35.2025.02.18.01.11.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 Feb 2025 01:11:58 -0800 (PST) Message-ID: Date: Tue, 18 Feb 2025 11:11:56 +0200 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC][PATCH 07/10] printk: export symbols for buffer address and length functions To: Sergey Senozhatsky , Christoph Hellwig Cc: linux-arm-msm@vger.kernel.org, linux-hardening@vger.kernel.org, kees@kernel.org, linux-kernel@vger.kernel.org, johannes@sipsolutions.net, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, andersson@kernel.org, konradybcio@kernel.org, tony.luck@intel.com, gpiccoli@igalia.com, pmladek@suse.com, rostedt@goodmis.org, john.ogness@linutronix.de, quic_mojha@quicinc.com, linux-arm-kernel@lists.infradead.org, kernel@quicinc.com References: <20250217101706.2104498-1-eugen.hristev@linaro.org> <20250217101706.2104498-8-eugen.hristev@linaro.org> <20250218-175733-neomutt-senozhatsky@chromium.org> From: Eugen Hristev Content-Language: en-US In-Reply-To: <20250218-175733-neomutt-senozhatsky@chromium.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/18/25 10:58, Sergey Senozhatsky wrote: > On (25/02/18 00:26), Christoph Hellwig wrote: >> On Mon, Feb 17, 2025 at 12:17:03PM +0200, Eugen Hristev wrote: >>> log_buf_addr_get() and log_buf_len_get() can be reused in another module, >>> export the symbols. >> >> Err, no way. > > Yeah I think we've been there before [1] > > [1] https://lore.kernel.org/all/20230905081902.321778-1-hch@lst.de/ Okay... in the line of the purpose of this patch series, I would like to be able to have the dmesg ready to be retrieved out of the kernel in case the kernel becomes unusable (due to various reasons as described in the cover letter). However to know exactly 'where' is the buffer stored I would need some way to point to it. Do you have any other suggestion on how to do this ? Using the kmsg_dump() API works only if the kernel/CPU can run code. Thanks for looking into the patches, Eugen