GHSA-3H7J-JQ4M-HXWQ
Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 15:31In the Linux kernel, the following vulnerability has been resolved:
xfs: fix under-reservation of blocks when repairing sf directories
Whilst running QA on XFS for-next as of 7.3-rc2 with MKFS_OPTIONS="-n size=8192", I observed the following (trimmed) dmesg splat:
XFS: Assertion failed: args->total >= dp->i_nblocks - nblks, file: fs/xfs/libxfs/xfs_da_btree.c, line: 2387 WARNING: fs/xfs/xfs_message.c:104 at assfail+0x46/0x4a [xfs], CPU#0: xfs_scrub/1426511 CPU: 0 UID: 0 PID: 1426511 Comm: xfs_scrub Tainted: G W 7.3.0-rc2-djwx #rc2 PREEMPT(lazy) 6e418570b606a39783b0e7e7b30dc407b965f9e8 Tainted: [W]=WARN RIP: 0010:assfail+0x46/0x4a [xfs] RSP: 0018:ffffc900010d7890 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffd1 RDX: 0000000000000000 RSI: 0000000000000021 RDI: ffffffffa059fd38 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000000a R11: 000000007fffffff R12: ffffc900010d7940 R13: ffff888368d8f980 R14: ffffc900010d7a48 R15: ffffc900010d78d0 FS: 00007f445c5ce680(0000) GS:ffff8884a97ea000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f443803b9a8 CR3: 0000000107a4b000 CR4: 00000000003506f0 Call Trace: xfs_da_grow_inode_int+0x2e0/0x300 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_dir2_grow_inode+0x6e/0x150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_dir2_sf_to_block+0x149/0x870 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_swap_prep+0xe2/0x110 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_swap+0xfb/0x2f0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_dir_rebuild_tree+0x99/0x100 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_directory+0x83/0x1c0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xrep_attempt+0x4f/0x1e0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_scrub_metadata+0x393/0x5b0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_ioc_scrubv_metadata+0x306/0x570 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] xfs_file_ioctl+0xa4f/0x1150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c] __x64_sys_ioctl+0x76/0xc0 do_syscall_64+0x7a/0x3b0 entry_SYSCALL_64_after_hwframe+0x4b/0x53
This is a consequence of commit 0fe77e57588b98, which added the following assertion to xfs_da_grow_inode_int:
ASSERT(args->total >= dp->i_nblocks - nblks);
Tracing this back to xrep_dir_swap_prep, I noticed that the xfs_da_args object that's passed to xfs_dir2_sf_to_block sets args->total to 1. This is incorrect because mkfs set the directory block size to 8k and the filesystem block size to 4k. In other words, args->total should be 2 here, not 1.
Dave Chinner tripped over the same problem with the same branch through a different channel -- his test setup set the fs block size to 1k, in which case the directory block size is still set to 4k. Here, args->total should be 4.
Changing the assignment of args->total to sc->mp->m_dir_geo->fsbcount makes the assertion go away, but that isn't a complete fix. In xrep_tempexch_estimate, we also incorrectly assume that a shortform conversion requires 1 fsblock when it should be m_dir_geo->fsbcount. Without that, we can under-reserve space in the transaction and cause a filesystem shutdown.
Note that the xfs_dabuf_nfsb helper will compute the correct value for directories and xattr, so we use that instead of open-coding the logic. Also fix xrep_xattr_swap_prep to assign args->total via xfs_dabuf_nfsb to avoid one logic bomb if we ever support multi-fsblock attrs.
Tripped-by: 0fe77e57588b98 ("xfs: assert the reservation covers each da fork growth")
{
"affected": [],
"aliases": [
"CVE-2026-97549"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-25T11:17:05Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix under-reservation of blocks when repairing sf directories\n\nWhilst running QA on XFS for-next as of 7.3-rc2 with MKFS_OPTIONS=\"-n\nsize=8192\", I observed the following (trimmed) dmesg splat:\n\n XFS: Assertion failed: args-\u003etotal \u003e= dp-\u003ei_nblocks - nblks, file: fs/xfs/libxfs/xfs_da_btree.c, line: 2387\n WARNING: fs/xfs/xfs_message.c:104 at assfail+0x46/0x4a [xfs], CPU#0: xfs_scrub/1426511\n CPU: 0 UID: 0 PID: 1426511 Comm: xfs_scrub Tainted: G W 7.3.0-rc2-djwx #rc2 PREEMPT(lazy) 6e418570b606a39783b0e7e7b30dc407b965f9e8\n Tainted: [W]=WARN\n RIP: 0010:assfail+0x46/0x4a [xfs]\n RSP: 0018:ffffc900010d7890 EFLAGS: 00010246\n RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffd1\n RDX: 0000000000000000 RSI: 0000000000000021 RDI: ffffffffa059fd38\n RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000\n R10: 000000000000000a R11: 000000007fffffff R12: ffffc900010d7940\n R13: ffff888368d8f980 R14: ffffc900010d7a48 R15: ffffc900010d78d0\n FS: 00007f445c5ce680(0000) GS:ffff8884a97ea000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f443803b9a8 CR3: 0000000107a4b000 CR4: 00000000003506f0\n Call Trace:\n \u003cTASK\u003e\n xfs_da_grow_inode_int+0x2e0/0x300 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xfs_dir2_grow_inode+0x6e/0x150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xfs_dir2_sf_to_block+0x149/0x870 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xrep_dir_swap_prep+0xe2/0x110 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xrep_dir_swap+0xfb/0x2f0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xrep_dir_rebuild_tree+0x99/0x100 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xrep_directory+0x83/0x1c0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xrep_attempt+0x4f/0x1e0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xfs_scrub_metadata+0x393/0x5b0 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xfs_ioc_scrubv_metadata+0x306/0x570 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n xfs_file_ioctl+0xa4f/0x1150 [xfs 5de2257e14108c136f11317e6bbb8ac77efd392c]\n __x64_sys_ioctl+0x76/0xc0\n do_syscall_64+0x7a/0x3b0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\nThis is a consequence of commit 0fe77e57588b98, which added the\nfollowing assertion to xfs_da_grow_inode_int:\n\n ASSERT(args-\u003etotal \u003e= dp-\u003ei_nblocks - nblks);\n\nTracing this back to xrep_dir_swap_prep, I noticed that the xfs_da_args\nobject that\u0027s passed to xfs_dir2_sf_to_block sets args-\u003etotal to 1.\nThis is incorrect because mkfs set the directory block size to 8k and\nthe filesystem block size to 4k. In other words, args-\u003etotal should be\n2 here, not 1.\n\nDave Chinner tripped over the same problem with the same branch through\na different channel -- his test setup set the fs block size to 1k, in\nwhich case the directory block size is still set to 4k. Here,\nargs-\u003etotal should be 4.\n\nChanging the assignment of args-\u003etotal to sc-\u003emp-\u003em_dir_geo-\u003efsbcount\nmakes the assertion go away, but that isn\u0027t a complete fix. In\nxrep_tempexch_estimate, we also incorrectly assume that a shortform\nconversion requires 1 fsblock when it should be m_dir_geo-\u003efsbcount.\nWithout that, we can under-reserve space in the transaction and cause a\nfilesystem shutdown.\n\nNote that the xfs_dabuf_nfsb helper will compute the correct value for\ndirectories and xattr, so we use that instead of open-coding the logic.\nAlso fix xrep_xattr_swap_prep to assign args-\u003etotal via xfs_dabuf_nfsb\nto avoid one logic bomb if we ever support multi-fsblock attrs.\n\nTripped-by: 0fe77e57588b98 (\"xfs: assert the reservation covers each da fork growth\")",
"id": "GHSA-3h7j-jq4m-hxwq",
"modified": "2026-09-25T15:31:42Z",
"published": "2026-09-25T12:31:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97549"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4d3c07591534517c633945c8d8e6526f10e3fabc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b8f46ca5cbd629ffb91489ad7f970b3837835b0a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b950e84acd072ac648ace4fea53c0b1212da4b2c"
}
],
"schema_version": "1.4.0",
"severity": []
}
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