{"id":"CVE-2026-97549","title":"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 fol…","summary":"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 fol…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 629fdaf5f5b1b7f7107ed4de04e0991a99501ced < b950e84acd072ac648ace4fea53c0b1212da4b2c","Linux >= 629fdaf5f5b1b7f7107ed4de04e0991a99501ced < 4d3c07591534517c633945c8d8e6526f10e3fabc","Linux 6.10"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T15:17:58.680","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97549","references":[{"url":"https://git.kernel.org/stable/c/4d3c07591534517c633945c8d8e6526f10e3fabc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b8f46ca5cbd629ffb91489ad7f970b3837835b0a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b950e84acd072ac648ace4fea53c0b1212da4b2c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.919Z","slug":"CVE-2026-97549","body":"## Overview\n\nIn 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->total >= dp->i_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  <TASK>\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->total >= dp->i_nblocks - nblks);\n\nTracing this back to xrep_dir_swap_prep, I noticed that the xfs_da_args\nobject that's passed to xfs_dir2_sf_to_block sets args->total 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->total 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->total should be 4.\n\nChanging the assignment of args->total to sc->mp->m_dir_geo->fsbcount\nmakes the assertion go away, but that isn't 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->fsbcount.\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->total 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\")\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}