mm/alloc_tag: clear codetag for pages allocated before page_ext initialization
Summary
| CVE | CVE-2026-46279 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-08 17:16:45 UTC |
| Updated | 2026-06-08 17:16:45 UTC |
| 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] <TASK> [ 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_l ---truncated--- |
Risk And Classification
EPSS: 0.000220000 probability, percentile 0.063970000 (date 2026-06-14)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected dcfe378c81f72f146890ce1dcfdcc742d3b66924 d5b495ba9de0423ef39f8bd86729a885870c7efe git | Not specified |
| CNA | Linux | Linux | affected dcfe378c81f72f146890ce1dcfdcc742d3b66924 b49dfabc38cad5e50af24f63edd124a10de3ebb6 git | Not specified |
| CNA | Linux | Linux | affected dcfe378c81f72f146890ce1dcfdcc742d3b66924 6b1842775a460245e97d36d3a67d0cfba7c4ff79 git | Not specified |
| CNA | Linux | Linux | affected 6.10 | Not specified |
| CNA | Linux | Linux | unaffected 6.10 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.27 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.4 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/b49dfabc38cad5e50af24f63edd124a10de3ebb6 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/6b1842775a460245e97d36d3a67d0cfba7c4ff79 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/d5b495ba9de0423ef39f8bd86729a885870c7efe | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.