From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from akranes.kaiser.cx (akranes.kaiser.cx [152.53.16.207]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E156B334372 for ; Fri, 31 Oct 2025 10:23:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=152.53.16.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761906207; cv=none; b=nxUsHUyzZdz2yHVxwfJCiGXxyYfbmauEEGclJzHyRkNuejqQIraUzC4AHvvmW8zNPnH54EwYpZUcIeTDSWQYVQ1pIiboU43akQw3bAenV6kAgzEJWJ2jP/5dHFvyDCJfk86d+U3oWkhBilmgg6DJQ3J8vOhkG+9s19aNTTGbaAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761906207; c=relaxed/simple; bh=rV78AJulqgBe/69BwJDzf+lU1/rnZMFS0t4vOpTfaU0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fNqMRG64T9VZq7eNHS4eFnLpWcDGIVrlRMUGlV7PUD35WbL0lymlBnIWlBirIcwapgPkfIKJ/k4OzIKooktLgR8v8QhsLSBM9X7jBjQxn1/oBlRqbRQv/48Rs51heKeNRtGQVVKtLxaCXWUPIgg3tUh7/jYRPrI0bfOhW1QDnFI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kaiser.cx; spf=pass smtp.mailfrom=kaiser.cx; arc=none smtp.client-ip=152.53.16.207 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kaiser.cx Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kaiser.cx Received: from martin by akranes.kaiser.cx with local (Exim 4.96) (envelope-from ) id 1vEmHa-0067HP-1L; Fri, 31 Oct 2025 11:22:58 +0100 Date: Fri, 31 Oct 2025 11:22:58 +0100 From: Martin Kaiser To: Andrew Morton Cc: "Liam R . 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251030193206.22bb773e697b6cc385d5aa67@linux-foundation.org> Sender: "Martin Kaiser,,," 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