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a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Ep5AJlsUvRo/Sl9Rg+NwP6D7Lq/wQPVEaLy1Gie9QQ4=; b=vV5nh+muii9KUwMXfoK65C9FPK aNSl0OiG0j4I+LFXc7WeA74kYOFf834TBtI7qS+ZEF0cf7hSHSrnoI47iOSAXQPCAXQU9fne6O/8R G2wk/XluU5ugbAZ7f5jU4JBscAk6nd/VyyPFhAk65/tq7U9wZjt9SJD8a8A/m2R6Cxj7l7C76kg9H 1KIPLAQYQ/Fv+JWvD04uouKwGYT/8gu4uHiCPUf9Bg4PxVdqeWdNvrfltP4AIW+MdO1/5WBfOmizl DellelcAiKmJM9KaaC82wP83/72jAdgWurCb/I4tMo/beG16KgajqNT/PO+VCT1shIIGmoQlyuzr0 Arg3hVEA==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xR6u3-00DA6f-37; Wed, 11 Nov 2026 11:54:12 +0000 Date: Wed, 11 Nov 2026 03:54:00 -0800 From: Breno Leitao To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, Linus Torvalds , Jann Horn , Josef Bacik , Chris Mason , Jeff Layton , NeilBrown , Eric Dumazet , Thomas Gleixner , Al Viro , Jonathan Corbet , Christoph Hellwig , Greg Kroah-Hartman , Joel Granados , Kees Cook , Jan Kara , Jan Kara , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-um@lists.infradead.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, platform-driver-x86@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, netfilter-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, ibm-acpi-devel@lists.sourceforge.net, jfs-discussion@lists.sourceforge.net, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, linux-atm-general@lists.sourceforge.net, Takashi Iwai , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, linux-debuggers@vger.kernel.org, Chuck Lever , stable@vger.kernel.org Subject: Re: [PATCH RFC 25/38] powerpc/crash_dump: check ioremap_cache() in copy_oldmem_page() Message-ID: References: <20261102-work-procfs-bugfixes-v1-0-59422ed3e465@kernel.org> <20261102-work-procfs-bugfixes-v1-25-59422ed3e465@kernel.org> X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261102-work-procfs-bugfixes-v1-25-59422ed3e465@kernel.org> X-Debian-User: leitao On Mon, Nov 02, 2026 at 03:21:40PM +0100, Christian Brauner wrote: > copy_oldmem_page() maps a page of the old kernel that isn't in the > linear mapping with ioremap_cache() and copies from it without checking > whether the mapping worked. If it didn't, the copy reads from an offset > into the NULL page. That oopses unless the copy happens to be a user > copy, whose exception table entries turn the fault into a short copy. > > Return -ENOMEM like the other architectures do. read_from_oldmem() > turns that into -EFAULT like any other short copy. > > Reported-by: Chris Mason > Fixes: 54c32021eb6f ("[PATCH] powerpc: Add arch-dependent copy_oldmem_page") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Brauner (Amutable) Reviewed-by: Breno Leitao