| From bippy-1.0.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21907: mm: memory-failure: update ttu flag inside unmap_poisoned_folio |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm: memory-failure: update ttu flag inside unmap_poisoned_folio |
| |
| Patch series "mm: memory_failure: unmap poisoned folio during migrate |
| properly", v3. |
| |
| Fix two bugs during folio migration if the folio is poisoned. |
| |
| |
| This patch (of 3): |
| |
| Commit 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to |
| TTU_HWPOISON") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON in |
| order to stop send SIGBUS signal when accessing an error page after a |
| memory error on a clean folio. However during page migration, anon folio |
| must be set with TTU_HWPOISON during unmap_*(). For pagecache we need |
| some policy just like the one in hwpoison_user_mappings to set this flag. |
| So move this policy from hwpoison_user_mappings to unmap_poisoned_folio to |
| handle this warning properly. |
| |
| Warning will be produced during unamp poison folio with the following log: |
| |
| ------------[ cut here ]------------ |
| WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 try_to_unmap_one+0x8fc/0xd3c |
| Modules linked in: |
| CPU: 1 UID: 0 PID: 365 Comm: bash Tainted: G W 6.13.0-rc1-00018-gacdb4bbda7ab #42 |
| Tainted: [W]=WARN |
| Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 |
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) |
| pc : try_to_unmap_one+0x8fc/0xd3c |
| lr : try_to_unmap_one+0x3dc/0xd3c |
| Call trace: |
| try_to_unmap_one+0x8fc/0xd3c (P) |
| try_to_unmap_one+0x3dc/0xd3c (L) |
| rmap_walk_anon+0xdc/0x1f8 |
| rmap_walk+0x3c/0x58 |
| try_to_unmap+0x88/0x90 |
| unmap_poisoned_folio+0x30/0xa8 |
| do_migrate_range+0x4a0/0x568 |
| offline_pages+0x5a4/0x670 |
| memory_block_action+0x17c/0x374 |
| memory_subsys_offline+0x3c/0x78 |
| device_offline+0xa4/0xd0 |
| state_store+0x8c/0xf0 |
| dev_attr_store+0x18/0x2c |
| sysfs_kf_write+0x44/0x54 |
| kernfs_fop_write_iter+0x118/0x1a8 |
| vfs_write+0x3a8/0x4bc |
| ksys_write+0x6c/0xf8 |
| __arm64_sys_write+0x1c/0x28 |
| invoke_syscall+0x44/0x100 |
| el0_svc_common.constprop.0+0x40/0xe0 |
| do_el0_svc+0x1c/0x28 |
| el0_svc+0x30/0xd0 |
| el0t_64_sync_handler+0xc8/0xcc |
| el0t_64_sync+0x198/0x19c |
| ---[ end trace 0000000000000000 ]--- |
| |
| [mawupeng1@huawei.com: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe] |
| |
| The Linux kernel CVE team has assigned CVE-2025-21907 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.3 with commit 6da6b1d4a7df8c35770186b53ef65d388398e139 and fixed in 6.12.19 with commit 608cc7deb428f1122ed426060233622ebf667b6e |
| Issue introduced in 6.3 with commit 6da6b1d4a7df8c35770186b53ef65d388398e139 and fixed in 6.13.7 with commit 425c12c076e6fc6b2cb04b9f960319d31dcabc76 |
| Issue introduced in 6.3 with commit 6da6b1d4a7df8c35770186b53ef65d388398e139 and fixed in 6.14 with commit b81679b1633aa43c0d973adfa816d78c1ed0d032 |
| Issue introduced in 6.1.16 with commit deab8114fb67dcb0e6293b665c3c7083fbadff17 |
| Issue introduced in 6.2.3 with commit 6dcf132fe236045bd7f50c008660ea086d09af1f |
| |
| 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-2025-21907 |
| 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: |
| mm/internal.h |
| mm/memory-failure.c |
| mm/memory_hotplug.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/608cc7deb428f1122ed426060233622ebf667b6e |
| https://git.kernel.org/stable/c/425c12c076e6fc6b2cb04b9f960319d31dcabc76 |
| https://git.kernel.org/stable/c/b81679b1633aa43c0d973adfa816d78c1ed0d032 |
