# CVE-2024-57975: linux: In the Linux kernel, the following vulnerability has been resolved: btrfs: do proper folio cleanup when run_delalloc... CVE-2024-57975 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2024-57975, released February 27, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2024-57975 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0026 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Feb 27, 2025 ## Description In the Linux kernel, the following vulnerability has been resolved: btrfs: do proper folio cleanup when run_delalloc_nocow() failed [BUG] With CONFIG_DEBUG_VM set, test case generic/476 has some chance to crash with the following VM_BUG_ON_FOLIO(): BTRFS error (device dm-3): cow_file_range failed, start 1146880 end 1253375 len 106496 ret -28 BTRFS error (device dm-3): run_delalloc_nocow failed, start 1146880 end 1253375 len 106496 ret -28 page: refcount:4 mapcount:0 mapping:00000000592787cc index:0x12 pfn:0x10664 aops:btrfs_aops [btrfs] ino:101 dentry name(?):"f1774" flags: 0x2fffff80004028(uptodate|lru|private|node=0|zone=2|lastcpupid=0xfffff) page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio)) ------------[ cut here ]------------ kernel BUG at mm/page-writeback.c:2992! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP CPU: 2 UID: 0 PID: 3943513 Comm: kworker/u24:15 Tainted: G OE 6.12.0-rc7-custom+ #87 Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs] pc : folio_clear_dirty_for_io+0x128/0x258 lr : folio_clear_dirty_for_io+0x128/0x258 Call trace: folio_clear_dirty_for_io+0x128/0x258 btrfs_folio_clamp_clear_dirty+0x80/0xd0 [btrfs] __process_folios_contig+0x154/0x268 [btrfs] extent_clear_unlock_delalloc+0x5c/0x80 [btrfs] run_delalloc_nocow+0x5f8/0x760 [btrfs] btrfs_run_delalloc_range+0xa8/0x220 [btrfs] writepage_delalloc+0x230/0x4c8 [btrfs] extent_writepage+0xb8/0x358 [btrfs] extent_write_cache_pages+0x21c/0x4e8 [btrfs] btrfs_writepages+0x94/0x150 [btrfs] do_writepages+0x74/0x190 filemap_fdatawrite_wbc+0x88/0xc8 start_delalloc_inodes+0x178/0x3a8 [btrfs] btrfs_start_delalloc_roots+0x174/0x280 [btrfs] shrink_delalloc+0x114/0x280 [btrfs] flush_space+0x250/0x2f8 [btrfs] btrfs_async_reclaim_data_space+0x180/0x228 [btrfs] process_one_work+0x164/0x408 worker_thread+0x25c/0x388 kthread+0x100/0x118 ret_from_fork+0x10/0x20 Code: 910a8021 a90363f7 a9046bf9 94012379 (d4210000) ---[ end trace 0000000000000000 ]--- [CAUSE] The first two lines of extra debug messages show the problem is caused by the error handling of run_delalloc_nocow(). E.g. we have the following dirtied range (4K blocksize 4K page size): 0 16K 32K |//////////////////////////////////////| | Pre-allocated | And the range [0, 16K) has a preallocated extent. - Enter run_delalloc_nocow() for range [0, 16K) Which found range [0, 16K) is preallocated, can do the proper NOCOW write. - Enter fallback_to_fow() for range [16K, 32K) Since the range [16K, 32K) is not backed by preallocated extent, we have to go COW. - cow_file_range() failed for range [16K, 32K) So cow_file_range() will do the clean up by clearing folio dirty, unlock the folios. Now the folios in range [16K, 32K) is unlocked. - Enter extent_clear_unlock_delalloc() from run_delalloc_nocow() Which is called with PAGE_START_WRITEBACK to start page writeback. But folios can only be marked writeback when it's properly locked, thus this triggered the VM_BUG_ON_FOLIO(). Furthermore there is another hidden but common bug that run_delalloc_nocow() is not clearing the folio dirty flags in its error handling path. This is the common bug shared between run_delalloc_nocow() and cow_file_range(). [FIX] - Clear folio dirty for range [@start, @cur_offset) Introduce a helper, cleanup_dirty_folios(), which will find and lock the folio in the range, clear the dirty flag and start/end the writeback, with the extra handling for the @locked_folio. - Introduce a helper to clear folio dirty, start and end writeback - Introduce a helper to record the last failed COW range end This is to trace which range we should skip, to avoid double unlocking. - Skip the failed COW range for the e ---truncated--- ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-uek ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.13-1 | [DEBIAN-CVE-2024-57975](https://patchblox.com/security/data/fix/linux/debian-cve-2024-57975.md) | Feb 27, 2025 | | Linux | linux Debian 14 | 6.12.13-1 | [DEBIAN-CVE-2024-57975](https://patchblox.com/security/data/fix/linux/debian-cve-2024-57975.md) | Feb 27, 2025 | --- Data as of 2026-11-08T19:12:23Z UTC. 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