CVE-2026-80734
- Source
- https://cve.org/CVERecord?id=CVE-2026-80734
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80734.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-80734
- Downstream
- Published
- 2026-09-03T08:21:50Z
- Modified
- 2026-09-23T03:30:29Z
- Severity
-
- 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- btrfs: initialize inode mapping flags for cached inodes
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
btrfs: initialize inode mapping flags for cached inodes
[BUG] When running generic/795 with 8K block size, 4K page size, the test always fails, triggering some ASSERT()s related to folio size:
795 (241074): drop_caches: 3 assertion failed: IS_ALIGNED(start, blocksize) && IS_ALIGNED(end + 1, blocksize), in extent_io.c:1404 (blocksize=8192 root=262 ino=258 start=16826368 end=16830463 mapping min order=0) ------------[ cut here ]------------ kernel BUG at extent_io.c:1404! Oops: invalid opcode: 0000 [#1] SMP CPU: 8 UID: 0 PID: 241105 Comm: fsstress Tainted: G OE 7.2.0-rc5-custom+ #442 PREEMPT(full) f4bfb352566f3949f29c233ce6f735050a03b245 Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:assert_folio_range.cold+0x3d/0x3f [btrfs] Call Trace: btrfs_read_folio+0x9e/0x170 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3] prepare_one_folio.constprop.0+0x104/0x2a0 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3] btrfs_buffered_write+0x285/0xa50 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3] btrfs_do_write_iter+0x1aa/0x210 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3] iter_file_splice_write+0x31a/0x540 direct_splice_actor+0x53/0x170 splice_direct_to_actor+0xe9/0x240 do_splice_direct+0x76/0xb0 vfs_copy_file_range+0x1fd/0x630 __x64_sys_copy_file_range+0xf9/0x220 do_syscall_64+0xe1/0x790 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ---[ end trace 0000000000000000 ]---
The ASSERT() itself is added by a later patch. The crash is triggered with that new debug patch, and without this fix.
[CAUSE] In the above case, the start 16826368 is properly 8K aligned, but the end (16830463 + 1) is not 8K aligned. Furthermore the mapping's minimal folio order is 0, not the expected 1 for 8K block size with 4K page size.
So this means some inodes do not have btrfs_set_inode_mapping_order() called on it.
The missing btrfs_set_inode_mapping_order() call happens for cached inodes, through the following events:
-
btrfs_create_new_inode() called for inode X Which properly sets minimal folio order for the VFS inode.
-
btrfs_update_inode() called for inode X Which calls btrfs_delayed_update_inode() to create a delayed_node into root->delayed_nodes xarray.
-
Drop cache/memory pressure, evicting in-memory inode X Which evicted the inode X, but delayed_node is still in root->delayed_nodes for future reuse.
-
btrfs_iget() for inode X called again
btrfs_iget() |- btrfs_iget_locked() | |- iget5_locked_rcu() | Which creates a new vfs_inode for btrfs, whose mapping still | has the minimal order as 0. | |- btrfs_read_locked_inode() |- btrfs_fill_inode() | |- btrfs_get_delayed_node() | Which found out the previous node, and use that delayed | node to initialize the new inode. | |- filled = true; |- if (filled) goto cache_index; Which skips the btrfs_update_inode_mapping_flags() and btrfs_set_inode_mapping_order() calls. So the inode still has minimal folio order set as 0, not the required 1.
Thus later page cache read will get a folio whose size is smaller than block size, as the mapping has its minimal folio order set as 0 not 1, then trigger the ASSERT().
[FIX] Move the btrfs_update_inode_mapping_flags() and btrfs_set_inode_mapping_order() calls under cache_index label, so that the mapping flags and minimal folio order is always set no matter if we have a cached inode.
-
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80734.json" }- References
-
- https://git.kernel.org/stable/c/0d26249671171ab759cb4fdce673554a690fa655
- https://git.kernel.org/stable/c/0ef349734a93227b45f65fc50a3311d1cc5f03e9
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80734.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-80734
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedecde48a1a6b3256bd49db8780bf37556b157783cFixed0d26249671171ab759cb4fdce673554a690fa655Fixed0ef349734a93227b45f65fc50a3311d1cc5f03e9
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedLast Affected01b002151539a4c2b27bfff9af033329a9b659e7Last Affectedae584726e6eddf6cfbe49b3f4a78b3197716b6f8
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.12.111Fixed6.13
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.14.6Fixed6.15