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Howlett" , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] maple_tree: fix tracepoint string pointers Message-ID: References: <20251030155537.87972-1-martin@kaiser.cx> <20251030193206.22bb773e697b6cc385d5aa67@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251030193206.22bb773e697b6cc385d5aa67@linux-foundation.org> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 125192000D X-Stat-Signature: 5odmb5jd5jexmfkktprtz3stym1sp1fu X-Rspam-User: X-HE-Tag: 1761906202-609403 X-HE-Meta: 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 XtrJuquI 5HFUHEvhXF0JaeDwfc2Z7xfZajK4MnhkGVyd7YbVqeWyihGUZXT7zHBgRq5A3CrgDeTZLMt9GpL505DUBXbsSjLuxCuLVkceWQBoqyEtdXyTMfbBZqq9A1m+KqBn5yfMOdq/FXGNzhcf0J7uh/Ih1uEijL080i0qsMK2QeXC6WzVgqbLMejQwo6MuxmTClCKCzhdmoa+firOWOSKwnI3EKe0JiMC7i8PBU7H0rG07xWOJczkjV2QFTrAzc7e9lqpJh9TGsqfiKMXsrX2/i2pMyUx01AIJV+5MSFGPkdWCpAnh4ys= 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: Thus wrote Andrew Morton (akpm@linux-foundation.org): > > - trace_ma_op(__func__, mas); > > + trace_ma_op(TP_FCT, mas); > What could cause the storage for __func__ to disappear as you suggest? I see your point. For __func__, the compiler generates a local symbol in .rodata that should always be accessible by its address. One case that doesn't work without my patch would be trace-cmd record to save the binary ringbuffer and trace-cmd report to parse it in userspace. The address of __func__ can't be dereferenced from userspace but tracepoint_string will add an entry to /sys/kernel/tracing/printk_formats Best regards, Martin