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Mon, 2 Nov 2026 14:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793629653; bh=v5t8qKNo68SCWoforDimF8hL2ZYL+p0Okj8bWoZ1JT0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=hvt3N63R16p2fDZtChXjcMwdKVbvtxfkoL2k4OxbkJ9NXiN3sUvoI90Anz8tghLzV tw7TRLB1mJI+ndKzKgYA8EusdDfCEFHDNDNB81AIW3QjjgCwg/TU6I079wNwJuekME GgYfwUhSITW0rfvdsRQDJf8rj9zB05fpKjF8xVxdybjPcer/CH1qH37gxEgqe+026Q OuFUuk+WcD3uSGWDc90qsgO7GgFfaxkgSrLrqyeXVxjbcarjoj5jc97EhboLO3/3O0 KcAvyFsBb08Hf5sOjHYp74WBf8FtRIs604ayotkQgHKNOSX4SCmldQ2ODja09nMv8N 2p+DzdlRSt69w== From: Christian Brauner Date: Mon, 02 Nov 2026 15:21:40 +0100 Subject: [PATCH RFC 25/38] powerpc/crash_dump: check ioremap_cache() in copy_oldmem_page() X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261102-work-procfs-bugfixes-v1-25-59422ed3e465@kernel.org> References: <20261102-work-procfs-bugfixes-v1-0-59422ed3e465@kernel.org> In-Reply-To: <20261102-work-procfs-bugfixes-v1-0-59422ed3e465@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: 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, "Christian Brauner (Amutable)" , Chuck Lever , stable@vger.kernel.org X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1312; i=brauner@kernel.org; h=from:subject:message-id; bh=2dbZnDPFapx3dAW5qeN54CL6hHWBvjsrs28L3h6tsIk=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS9mJOT3t4mUyCor3Li661vsa/yObLOB7XeUji6boXCC secScIdHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABPh7WFkeC/LwqiVxiMX6PN4 IXM3/4WNlnf/rlkw4SVrp5CBfEGgISND+4Gm4KSDXU7MDmLZHq5y5z4dYP+8p+ODD1PYa4mTduu YAA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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) --- arch/powerpc/kernel/crash_dump.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c index 103b6605dd68..1543917bd3e1 100644 --- a/arch/powerpc/kernel/crash_dump.c +++ b/arch/powerpc/kernel/crash_dump.c @@ -86,6 +86,8 @@ ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, csize = copy_to_iter(vaddr + offset, csize, iter); } else { vaddr = ioremap_cache(paddr, PAGE_SIZE); + if (!vaddr) + return -ENOMEM; csize = copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); } -- 2.53.0