CVE-2025-21907

MEDIUM
Published Apr 1, 2025 Modified Oct 31, 2025

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 ]--- [[email protected]: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe]

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Frequently Asked Questions

What is CVE-2025-21907? +
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 ]--- [[email protected]: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe] It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2025-21907? +
CVE-2025-21907 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2025-21907? +
CVE-2025-21907 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-21907? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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