From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 14C0F37BE7D; Sun, 26 Apr 2026 19:54:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777233287; cv=none; b=T6I9XOvL5Q5n1Q8MeWmZnlBYvtH4uKTBpg8dA0CaLGkD1k5F5lbH8rruxFnJq+j2JeVVq6E2XC5p8+264rxfNRYzr51WGJnhBkZUBGWhGLWMMRzf/Efngd7x/JCtPVp06JNcPx45kp2H/MlcCtW7ZwgrNFkq6VNJbL3dyivNdys= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777233287; c=relaxed/simple; bh=3/bt0Nrq1HoyOJ+6zLl4F3BQRUYkONWlF2cbteo/YIU=; h=Date:To:From:Subject:Message-Id; b=lZXGl6xtnEDONAxsC4Z3dsvUJOqt2OzAFYPT+ZfdVZg/pPxOu1B0fExL7ZjbPrXHZKMJG+LGu5KhxdIQ84yfOgrTz6zsj7OOqqmnV3QRgmr6tNtls1bLiT/CRUJ1JKOVG3caL0nibD6IEOd3VXuYNDOmb+WpmHSe1DSI5ILLBjs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=U5zreVdc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="U5zreVdc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D613DC2BCAF; Sun, 26 Apr 2026 19:54:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777233286; bh=3/bt0Nrq1HoyOJ+6zLl4F3BQRUYkONWlF2cbteo/YIU=; h=Date:To:From:Subject:From; b=U5zreVdcjSlrvgOBwUDnXJf/MhRQQ2/pbrOFCFLyfgIJwHBOzV58FkNteTa7wJGGu cjP6ZNE2XMzk3FBe/AwL8yzqLoqj4TkQFQgd3VC1tUU7XH2ba1OoaMw4ndCYl6YKrT oQe8W2aD40qNIC58UpoZXyuurGf0ngb5Lq1xGc6M= Date: Sun, 26 Apr 2026 12:54:46 -0700 To: mm-commits@vger.kernel.org,surenb@google.com,stable@vger.kernel.org,rppt@kernel.org,osalvador@suse.de,npiggin@gmail.com,mpe@ellerman.id.au,mhocko@suse.com,maddy@linux.ibm.com,ljs@kernel.org,liam@infradead.org,joao.m.martins@oracle.com,david@kernel.org,aneesh.kumar@linux.ibm.com,songmuchun@bytedance.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path.patch added to mm-new branch Message-Id: <20260426195446.D613DC2BCAF@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/memory_hotplug: fix incorrect altmap passing in error path has been added to the -mm mm-new branch. Its filename is mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Muchun Song Subject: mm/memory_hotplug: fix incorrect altmap passing in error path Date: Sun, 26 Apr 2026 17:26:36 +0800 In create_altmaps_and_memory_blocks(), when arch_add_memory() succeeds with memmap_on_memory enabled, the vmemmap pages are allocated from params.altmap. If create_memory_block_devices() subsequently fails, the error path calls arch_remove_memory() with a NULL altmap instead of params.altmap. This is a bug that could lead to memory corruption. Since altmap is NULL, vmemmap_free() falls back to freeing the vmemmap pages into the system buddy allocator via free_pages() instead of the altmap. arch_remove_memory() then immediately destroys the physical linear mapping for this memory. This injects unowned pages into the buddy allocator, causing machine checks or memory corruption if the system later attempts to allocate and use those freed pages. Fix this by passing params.altmap to arch_remove_memory() in the error path. Link: https://lore.kernel.org/20260426092640.375967-3-songmuchun@bytedance.com Fixes: 6b8f0798b85a ("mm/memory_hotplug: split memmap_on_memory requests across memblocks") Signed-off-by: Muchun Song Acked-by: David Hildenbrand (Arm) Cc: "Aneesh Kumar K.V" Cc: Joao Martins Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path +++ a/mm/memory_hotplug.c @@ -1469,7 +1469,7 @@ static int create_altmaps_and_memory_blo ret = create_memory_block_devices(cur_start, memblock_size, nid, params.altmap, group); if (ret) { - arch_remove_memory(cur_start, memblock_size, NULL); + arch_remove_memory(cur_start, memblock_size, params.altmap); kfree(params.altmap); goto out; } _ Patches currently in -mm which might be from songmuchun@bytedance.com are mm-memory_hotplug-fix-memory-block-reference-leak-on-remove.patch drivers-base-memory-fix-memory-block-reference-leak-in-poison-accounting.patch mm-sparse-remove-sparse-buffer-pre-allocation-mechanism.patch mm-sparse-vmemmap-fix-vmemmap-accounting-underflow.patch mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path.patch mm-sparse-vmemmap-pass-pgmap-argument-to-memory-deactivation-paths.patch mm-sparse-vmemmap-fix-dax-vmemmap-accounting-with-optimization.patch mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages.patch mm-mm_init-fix-uninitialized-struct-pages-for-zone_device.patch