UBUNTU-CVE-2025-21722
In the Linux kernel, the following vulnerability has been resolved: nilfs2: do not force clear folio if buffer is referenced Patch series "nilfs2: protect busy buffer heads from being force-cleared". This series fixes the buffer head state inconsistency issues reported by syzbot that occurs when the filesystem is corrupted and falls back to read-only, and the associated buffer head use-after-free issue. This patch (of 2): Syzbot has reported that after nilfs2 detects filesystem corruption and falls back to read-only, inconsistencies in the buffer state may occur. One of the inconsistencies is that when nilfs2 calls mark_buffer_dirty() to set a data or metadata buffer as dirty, but it detects that the buffer is not in the uptodate state: WARNING: CPU: 0 PID: 6049 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520 fs/buffer.c:1177 ... Call Trace: <TASK> nilfs_palloc_commit_alloc_entry+0x4b/0x160 fs/nilfs2/alloc.c:598 nilfs_ifile_create_inode+0x1dd/0x3a0 fs/nilfs2/ifile.c:73 nilfs_new_inode+0x254/0x830 fs/nilfs2/inode.c:344 nilfs_mkdir+0x10d/0x340 fs/nilfs2/namei.c:218 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdirat fs/namei.c:4295 [inline] __se_sys_mkdirat fs/namei.c:4293 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The other is when nilfs_btree_propagate(), which propagates the dirty state to the ancestor nodes of a b-tree that point to a dirty buffer, detects that the origin buffer is not dirty, even though it should be: WARNING: CPU: 0 PID: 5245 at fs/nilfs2/btree.c:2089 nilfs_btree_propagate+0xc79/0xdf0 fs/nilfs2/btree.c:2089 ... Call Trace: <TASK> nilfs_bmap_propagate+0x75/0x120 fs/nilfs2/bmap.c:345 nilfs_collect_file_data+0x4d/0xd0 fs/nilfs2/segment.c:587 nilfs_segctor_apply_buffers+0x184/0x340 fs/nilfs2/segment.c:1006 nilfs_segctor_scan_file+0x28c/0xa50 fs/nilfs2/segment.c:1045 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1216 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1540 [inline] nilfs_segctor_do_construct+0x1c28/0x6b90 fs/nilfs2/segment.c:2115 nilfs_segctor_construct+0x181/0x6b0 fs/nilfs2/segment.c:2479 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2587 [inline] nilfs_segctor_thread+0x69e/0xe80 fs/nilfs2/segment.c:2701 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Both of these issues are caused by the callbacks that handle the page/folio write requests, forcibly clear various states, including the working state of the buffers they hold, at unexpected times when they detect read-only fallback. Fix these issues by checking if the buffer is referenced before clearing the page/folio state, and skipping the clear if it is.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
39 explicit affected versions
45 explicit affected versions
63 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
73 explicit affected versions
24 explicit affected versions
58 explicit affected versions
76 explicit affected versions
66 explicit affected versions
59 explicit affected versions
10 explicit affected versions
17 explicit affected versions
24 explicit affected versions
65 explicit affected versions
191 explicit affected versions
7 explicit affected versions
64 explicit affected versions
21 explicit affected versions
104 explicit affected versions
13 explicit affected versions
77 explicit affected versions
23 explicit affected versions
35 explicit affected versions
25 explicit affected versions
23 explicit affected versions
18 explicit affected versions
24 explicit affected versions
109 explicit affected versions
64 explicit affected versions
26 explicit affected versions
106 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
114 explicit affected versions
31 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
60 explicit affected versions
27 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
7 explicit affected versions
56 explicit affected versions
12 explicit affected versions
14 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
93 explicit affected versions
12 explicit affected versions
109 explicit affected versions
117 explicit affected versions
12 explicit affected versions
21 explicit affected versions
104 explicit affected versions
113 explicit affected versions
19 explicit affected versions
18 explicit affected versions
13 explicit affected versions
10 explicit affected versions
181 explicit affected versions
37 explicit affected versions
5 explicit affected versions
13 explicit affected versions
19 explicit affected versions
10 explicit affected versions
40 explicit affected versions
1 explicit affected versions
26 explicit affected versions
13 explicit affected versions
14 explicit affected versions
1 explicit affected versions
29 explicit affected versions
96 explicit affected versions
13 explicit affected versions
70 explicit affected versions
20 explicit affected versions
21 explicit affected versions
1 explicit affected versions
87 explicit affected versions
65 explicit affected versions
108 explicit affected versions
28 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
1 explicit affected versions
107 explicit affected versions
11 explicit affected versions
12 explicit affected versions
130 explicit affected versions
7 explicit affected versions
12 explicit affected versions
107 explicit affected versions
2 explicit affected versions
56 explicit affected versions
50 explicit affected versions
122 explicit affected versions
66 explicit affected versions
158 explicit affected versions
144 explicit affected versions
10 explicit affected versions
26 explicit affected versions
25 explicit affected versions
41 explicit affected versions
1 explicit affected versions
14 explicit affected versions
26 explicit affected versions
13 explicit affected versions
26 explicit affected versions
130 explicit affected versions
64 explicit affected versions
16 explicit affected versions
67 explicit affected versions
29 explicit affected versions
54 explicit affected versions
3 explicit affected versions
84 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
74 explicit affected versions
51 explicit affected versions
83 explicit affected versions
18 explicit affected versions
23 explicit affected versions
12 explicit affected versions
53 explicit affected versions
27 explicit affected versions
40 explicit affected versions
1 explicit affected versions
1 explicit affected versions
88 explicit affected versions
22 explicit affected versions
8 explicit affected versions
30 explicit affected versions
5 explicit affected versions
8 explicit affected versions
1 explicit affected versions
10 explicit affected versions
7 explicit affected versions
25 explicit affected versions
13 explicit affected versions
96 explicit affected versions
13 explicit affected versions
59 explicit affected versions
7 explicit affected versions
8 explicit affected versions
85 explicit affected versions
57 explicit affected versions
10 explicit affected versions
12 explicit affected versions
15 explicit affected versions
94 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
30 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
55 explicit affected versions
11 explicit affected versions
19 explicit affected versions
7 explicit affected versions
66 explicit affected versions
7 explicit affected versions
35 explicit affected versions
90 explicit affected versions
67 explicit affected versions
134 explicit affected versions
113 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
64 explicit affected versions
104 explicit affected versions
56 explicit affected versions
13 explicit affected versions
43 explicit affected versions
62 explicit affected versions
137 explicit affected versions
158 explicit affected versions
10 explicit affected versions
8 explicit affected versions
24 explicit affected versions
14 explicit affected versions
92 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
60 explicit affected versions
19 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: nilfs2: do not force clear folio if buffer is referenced Patch series "nilfs2: protect busy buffer heads from being force-cleared". This series fixes the buffer head state inconsistency issues reported by syzbot that occurs when the filesystem is corrupted and falls back to read-only, and the associated buffer head use-after-free issue. This patch (of 2): Syzbot has reported that after nilfs2 detects filesystem corruption and falls back to read-only, inconsistencies in the buffer state may occur. One of the inconsistencies is that when nilfs2 calls mark_buffer_dirty() to set a data or metadata buffer as dirty, but it detects that the buffer is not in the uptodate state: WARNING: CPU: 0 PID: 6049 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520 fs/buffer.c:1177 ... Call Trace: <TASK> nilfs_palloc_commit_alloc_entry+0x4b/0x160 fs/nilfs2/alloc.c:598 nilfs_ifile_create_inode+0x1dd/0x3a0 fs/nilfs2/ifile.c:73 nilfs_new_inode+0x254/0x830 fs/nilfs2/inode.c:344 nilfs_mkdir+0x10d/0x340 fs/nilfs2/namei.c:218 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdirat fs/namei.c:4295 [inline] __se_sys_mkdirat fs/namei.c:4293 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The other is when nilfs_btree_propagate(), which propagates the dirty state to the ancestor nodes of a b-tree that point to a dirty buffer, detects that the origin buffer is not dirty, even though it should be: WARNING: CPU: 0 PID: 5245 at fs/nilfs2/btree.c:2089 nilfs_btree_propagate+0xc79/0xdf0 fs/nilfs2/btree.c:2089 ... Call Trace: <TASK> nilfs_bmap_propagate+0x75/0x120 fs/nilfs2/bmap.c:345 nilfs_collect_file_data+0x4d/0xd0 fs/nilfs2/segment.c:587 nilfs_segctor_apply_buffers+0x184/0x340 fs/nilfs2/segment.c:1006 nilfs_segctor_scan_file+0x28c/0xa50 fs/nilfs2/segment.c:1045 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1216 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1540 [inline] nilfs_segctor_do_construct+0x1c28/0x6b90 fs/nilfs2/segment.c:2115 nilfs_segctor_construct+0x181/0x6b0 fs/nilfs2/segment.c:2479 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2587 [inline] nilfs_segctor_thread+0x69e/0xe80 fs/nilfs2/segment.c:2701 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Both of these issues are caused by the callbacks that handle the page/folio write requests, forcibly clear various states, including the working state of the buffers they hold, at unexpected times when they detect read-only fallback. Fix these issues by checking if the buffer is referenced before clearing the page/folio state, and skipping the clear if it is.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/ca76bb226bf47ff04c782cacbd299f12ddee1ec1
- https://git.kernel.org/stable/c/1098bb8d52419d262a3358d099a1598a920b730f
- https://git.kernel.org/stable/c/19296737024cd220a1d6590bf4c092bca8c99497
- https://git.kernel.org/stable/c/557ccf5e49f1fb848a29698585bcab2e50a597ef
- https://git.kernel.org/stable/c/ca76bb226bf47ff04c782cacbd299f12ddee1ec1
- https://ubuntu.com/security/CVE-2025-21722
- https://ubuntu.com/security/notices/USN-7510-1
- https://ubuntu.com/security/notices/USN-7510-2
- https://ubuntu.com/security/notices/USN-7510-3
- https://ubuntu.com/security/notices/USN-7510-4
- https://ubuntu.com/security/notices/USN-7510-5
- https://ubuntu.com/security/notices/USN-7510-6
- https://ubuntu.com/security/notices/USN-7510-7
- https://ubuntu.com/security/notices/USN-7510-8
- https://ubuntu.com/security/notices/USN-7511-1
- https://ubuntu.com/security/notices/USN-7511-2
- https://ubuntu.com/security/notices/USN-7511-3
- https://ubuntu.com/security/notices/USN-7512-1
- https://ubuntu.com/security/notices/USN-7516-1
- https://ubuntu.com/security/notices/USN-7516-2
- https://ubuntu.com/security/notices/USN-7516-3
- https://ubuntu.com/security/notices/USN-7516-4
- https://ubuntu.com/security/notices/USN-7516-5
- https://ubuntu.com/security/notices/USN-7516-6
- https://ubuntu.com/security/notices/USN-7516-7
- https://ubuntu.com/security/notices/USN-7516-8
- https://ubuntu.com/security/notices/USN-7516-9
- https://ubuntu.com/security/notices/USN-7517-1
- https://ubuntu.com/security/notices/USN-7517-2
- https://ubuntu.com/security/notices/USN-7517-3
- https://ubuntu.com/security/notices/USN-7518-1
- https://ubuntu.com/security/notices/USN-7539-1
- https://ubuntu.com/security/notices/USN-7540-1
- https://ubuntu.com/security/notices/USN-7593-1
- https://ubuntu.com/security/notices/USN-7602-1
- https://ubuntu.com/security/notices/USN-7640-1
- https://ubuntu.com/security/notices/USN-7651-1
- https://ubuntu.com/security/notices/USN-7651-2
- https://ubuntu.com/security/notices/USN-7651-3
- https://ubuntu.com/security/notices/USN-7651-4
- https://ubuntu.com/security/notices/USN-7651-5
- https://ubuntu.com/security/notices/USN-7651-6
- https://ubuntu.com/security/notices/USN-7652-1
- https://ubuntu.com/security/notices/USN-7653-1
- https://ubuntu.com/security/notices/USN-7737-1
- https://ubuntu.com/security/notices/USN-7907-1
- https://ubuntu.com/security/notices/USN-7907-2
- https://ubuntu.com/security/notices/USN-7907-3
- https://ubuntu.com/security/notices/USN-7907-4
- https://ubuntu.com/security/notices/USN-7907-5
- https://ubuntu.com/security/notices/USN-7930-1
- https://ubuntu.com/security/notices/USN-7930-2
- https://ubuntu.com/security/notices/USN-7937-1
- https://www.cve.org/CVERecord?id=CVE-2025-21722