From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 80D973BB699 for ; Mon, 8 Jun 2026 15:42:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780933331; cv=none; b=DvwTQKIs8gUG76qykhWCcRnwsF4CN0HkoPqqGQCwPnDEjiKU0iXN87GaaeTnGDebUSQCvjwWM9jI+aBhJ5ULzfKsQg2ZLpEqlxa/ifN9y5FYcyv5rWAA8yb78H3l6YsGL/UB6zHDL6PltD0dp+ETBOo88BJ3D5R4EIRyIC4OLXE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780933331; c=relaxed/simple; bh=nnzs5IYD6LWc9yzGpWbi0iW+zZv+X3JkXG3K5e/EglI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UhsvPyd91b1qLrQxi6iJSSl4IM7/bFlLppkfc7f9g/nspkyJz3p9fmQWOmfmxQkp5ikwrdv95BVMi03ghDIasgB6AlgBPNAsAis6m6N0sQn3/Ehm1Lela4rigJdYEWXfeeD6XiZ/u+vNFHOae1p5foBOGGV/PF76iwd+/CWlFzw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LtWTGtRV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LtWTGtRV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC40D1F00893; Mon, 8 Jun 2026 15:42:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780933330; bh=nuUt5dtLpFuAj7FFufS5kXaHrcdkLkz9gVyLDVHg/n8=; h=From:To:Cc:Subject:Date:Reply-To; b=LtWTGtRVOrkuoK2npm9ZMY/weug9W7foqU5vqZwcuDraZaXwfDmk6O4D7dkFt9QuB 5l2hh3rE3fWJxzSoEsRQ2BUglRAbtJqWe/Vwrbp56Zfk7/R421np6s6vkQFWz4sJbd p2SscggjwOog2zCmBiNANPLenkPnFJrmkinanqDc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-46279: mm/alloc_tag: clear codetag for pages allocated before page_ext initialization Date: Mon, 8 Jun 2026 17:40:43 +0200 Message-ID: <2026060841-CVE-2026-46279-dc4a@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6889; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=VvZ8bVnPaWoG/m7K07zEry2qq5BCDK70yp2opOw+6GE=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlqjyrNHrbHfEl3cJgzo/i6h/DcdZkxhuLyd829UmwCf 1z4PXN7RywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEwk9xHD/NhU62/SFlc+rtlm eMLt8LYz01bJPmVYMOH0Whbn3L7zLB+Eeps2nlgQovnnPAA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: mm/alloc_tag: clear codetag for pages allocated before page_ext initialization Due to initialization ordering, page_ext is allocated and initialized relatively late during boot. Some pages have already been allocated and freed before page_ext becomes available, leaving their codetag uninitialized. A clear example is in init_section_page_ext(): alloc_page_ext() calls kmemleak_alloc(). If the slab cache has no free objects, it falls back to the buddy allocator to allocate memory. However, at this point page_ext is not yet fully initialized, so these newly allocated pages have no codetag set. These pages may later be reclaimed by KASAN, which causes the warning to trigger when they are freed because their codetag ref is still empty. Use a global array to track pages allocated before page_ext is fully initialized. The array size is fixed at 8192 entries, and will emit a warning if this limit is exceeded. When page_ext initialization completes, set their codetag to empty to avoid warnings when they are freed later. This warning is only observed with CONFIG_MEM_ALLOC_PROFILING_DEBUG=Y and mem_profiling_compressed disabled: [ 9.582133] ------------[ cut here ]------------ [ 9.582137] alloc_tag was not set [ 9.582139] WARNING: ./include/linux/alloc_tag.h:164 at __pgalloc_tag_sub+0x40f/0x550, CPU#5: systemd/1 [ 9.582190] CPU: 5 UID: 0 PID: 1 Comm: systemd Not tainted 7.0.0-rc4 #1 PREEMPT(lazy) [ 9.582192] Hardware name: Red Hat KVM, BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 9.582194] RIP: 0010:__pgalloc_tag_sub+0x40f/0x550 [ 9.582196] Code: 00 00 4c 29 e5 48 8b 05 1f 88 56 05 48 8d 4c ad 00 48 8d 2c c8 e9 87 fd ff ff 0f 0b 0f 0b e9 f3 fe ff ff 48 8d 3d 61 2f ed 03 <67> 48 0f b9 3a e9 b3 fd ff ff 0f 0b eb e4 e8 5e cd 14 02 4c 89 c7 [ 9.582197] RSP: 0018:ffffc9000001f940 EFLAGS: 00010246 [ 9.582200] RAX: dffffc0000000000 RBX: 1ffff92000003f2b RCX: 1ffff110200d806c [ 9.582201] RDX: ffff8881006c0360 RSI: 0000000000000004 RDI: ffffffff9bc7b460 [ 9.582202] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff3a62324 [ 9.582203] R10: ffffffff9d311923 R11: 0000000000000000 R12: ffffea0004001b00 [ 9.582204] R13: 0000000000002000 R14: ffffea0000000000 R15: ffff8881006c0360 [ 9.582206] FS: 00007ffbbcf2d940(0000) GS:ffff888450479000(0000) knlGS:0000000000000000 [ 9.582208] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9.582210] CR2: 000055ee3aa260d0 CR3: 0000000148b67005 CR4: 0000000000770ef0 [ 9.582211] PKRU: 55555554 [ 9.582212] Call Trace: [ 9.582213] [ 9.582214] ? __pfx___pgalloc_tag_sub+0x10/0x10 [ 9.582216] ? check_bytes_and_report+0x68/0x140 [ 9.582219] __free_frozen_pages+0x2e4/0x1150 [ 9.582221] ? __free_slab+0xc2/0x2b0 [ 9.582224] qlist_free_all+0x4c/0xf0 [ 9.582227] kasan_quarantine_reduce+0x15d/0x180 [ 9.582229] __kasan_slab_alloc+0x69/0x90 [ 9.582232] kmem_cache_alloc_noprof+0x14a/0x500 [ 9.582234] do_getname+0x96/0x310 [ 9.582237] do_readlinkat+0x91/0x2f0 [ 9.582239] ? __pfx_do_readlinkat+0x10/0x10 [ 9.582240] ? get_random_bytes_user+0x1df/0x2c0 [ 9.582244] __x64_sys_readlinkat+0x96/0x100 [ 9.582246] do_syscall_64+0xce/0x650 [ 9.582250] ? __x64_sys_getrandom+0x13a/0x1e0 [ 9.582252] ? __pfx___x64_sys_getrandom+0x10/0x10 [ 9.582254] ? do_syscall_64+0x114/0x650 [ 9.582255] ? ksys_read+0xfc/0x1d0 [ 9.582258] ? __pfx_ksys_read+0x10/0x10 [ 9.582260] ? do_syscall_64+0x114/0x650 [ 9.582262] ? do_syscall_64+0x114/0x650 [ 9.582264] ? __pfx_fput_close_sync+0x10/0x10 [ 9.582266] ? file_close_fd_locked+0x178/0x2a0 [ 9.582268] ? __x64_sys_faccessat2+0x96/0x100 [ 9.582269] ? __x64_sys_close+0x7d/0xd0 [ 9.582271] ? do_syscall_64+0x114/0x650 [ 9.582273] ? do_syscall_64+0x114/0x650 [ 9.582275] ? clear_bhb_loop+0x50/0xa0 [ 9.582277] ? clear_bhb_loop+0x50/0xa0 [ 9.582279] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 9.582280] RIP: 0033:0x7ffbbda345ee [ 9.582282] Code: 0f 1f 40 00 48 8b 15 29 38 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 0f 1f 40 00 f3 0f 1e fa 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d fa 37 0d 00 f7 d8 64 89 01 48 [ 9.582284] RSP: 002b:00007ffe2ad8de58 EFLAGS: 00000202 ORIG_RAX: 000000000000010b [ 9.582286] RAX: ffffffffffffffda RBX: 000055ee3aa25570 RCX: 00007ffbbda345ee [ 9.582287] RDX: 000055ee3aa25570 RSI: 00007ffe2ad8dee0 RDI: 00000000ffffff9c [ 9.582288] RBP: 0000000000001000 R08: 0000000000000003 R09: 0000000000001001 [ 9.582289] R10: 0000000000001000 R11: 0000000000000202 R12: 0000000000000033 [ 9.582290] R13: 00007ffe2ad8dee0 R14: 00000000ffffff9c R15: 00007ffe2ad8deb0 [ 9.582292] [ 9.582293] ---[ end trace 0000000000000000 ]--- The Linux kernel CVE team has assigned CVE-2026-46279 to this issue. Affected and fixed versions =========================== Issue introduced in 6.10 with commit dcfe378c81f72f146890ce1dcfdcc742d3b66924 and fixed in 6.18.27 with commit d5b495ba9de0423ef39f8bd86729a885870c7efe Issue introduced in 6.10 with commit dcfe378c81f72f146890ce1dcfdcc742d3b66924 and fixed in 7.0.4 with commit b49dfabc38cad5e50af24f63edd124a10de3ebb6 Issue introduced in 6.10 with commit dcfe378c81f72f146890ce1dcfdcc742d3b66924 and fixed in 7.1-rc1 with commit 6b1842775a460245e97d36d3a67d0cfba7c4ff79 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-46279 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: include/linux/alloc_tag.h include/linux/pgalloc_tag.h lib/alloc_tag.c mm/page_alloc.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/d5b495ba9de0423ef39f8bd86729a885870c7efe https://git.kernel.org/stable/c/b49dfabc38cad5e50af24f63edd124a10de3ebb6 https://git.kernel.org/stable/c/6b1842775a460245e97d36d3a67d0cfba7c4ff79