ghsa-rv8h-hrgv-p5cw
Vulnerability from github
Published
2025-02-27 03:34
Modified
2025-02-27 03:34
Details

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix assertion failure when splitting ordered extent after transaction abort

If while we are doing a direct IO write a transaction abort happens, we mark all existing ordered extents with the BTRFS_ORDERED_IOERR flag (done at btrfs_destroy_ordered_extents()), and then after that if we enter btrfs_split_ordered_extent() and the ordered extent has bytes left (meaning we have a bio that doesn't cover the whole ordered extent, see details at btrfs_extract_ordered_extent()), we will fail on the following assertion at btrfs_split_ordered_extent():

ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));

because the BTRFS_ORDERED_IOERR flag is set and the definition of BTRFS_ORDERED_TYPE_FLAGS is just the union of all flags that identify the type of write (regular, nocow, prealloc, compressed, direct IO, encoded).

Fix this by returning an error from btrfs_extract_ordered_extent() if we find the BTRFS_ORDERED_IOERR flag in the ordered extent. The error will be the error that resulted in the transaction abort or -EIO if no transaction abort happened.

This was recently reported by syzbot with the following trace:

FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 fail_dump lib/fault-inject.c:53 [inline] should_fail_ex+0x3b0/0x4e0 lib/fault-inject.c:154 should_failslab+0xac/0x100 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4072 [inline] slab_alloc_node mm/slub.c:4148 [inline] __do_kmalloc_node mm/slub.c:4297 [inline] __kmalloc_noprof+0xdd/0x4c0 mm/slub.c:4310 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] btrfs_chunk_alloc_add_chunk_item+0x244/0x1100 fs/btrfs/volumes.c:5742 reserve_chunk_space+0x1ca/0x2c0 fs/btrfs/block-group.c:4292 check_system_chunk fs/btrfs/block-group.c:4319 [inline] do_chunk_alloc fs/btrfs/block-group.c:3891 [inline] btrfs_chunk_alloc+0x77b/0xf80 fs/btrfs/block-group.c:4187 find_free_extent_update_loop fs/btrfs/extent-tree.c:4166 [inline] find_free_extent+0x42d1/0x5810 fs/btrfs/extent-tree.c:4579 btrfs_reserve_extent+0x422/0x810 fs/btrfs/extent-tree.c:4672 btrfs_new_extent_direct fs/btrfs/direct-io.c:186 [inline] btrfs_get_blocks_direct_write+0x706/0xfa0 fs/btrfs/direct-io.c:321 btrfs_dio_iomap_begin+0xbb7/0x1180 fs/btrfs/direct-io.c:525 iomap_iter+0x697/0xf60 fs/iomap/iter.c:90 __iomap_dio_rw+0xeb9/0x25b0 fs/iomap/direct-io.c:702 btrfs_dio_write fs/btrfs/direct-io.c:775 [inline] btrfs_direct_write+0x610/0xa30 fs/btrfs/direct-io.c:880 btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397 do_iter_readv_writev+0x600/0x880 vfs_writev+0x376/0xba0 fs/read_write.c:1050 do_pwritev fs/read_write.c:1146 [inline] __do_sys_pwritev2 fs/read_write.c:1204 [inline] __se_sys_pwritev2+0x196/0x2b0 fs/read_write.c:1195 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 RIP: 0033:0x7f1281f85d29 RSP: 002b:00007f12819fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007f1282176080 RCX: 00007f1281f85d29 RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000005 RBP: 00007f12819fe090 R08: 0000000000000000 R09: 0000000000000003 R10: 0000000000007000 R11: 0000000000000246 R12: 0000000000000002 R13: 0000000000000000 R14: 00007f1282176080 R15: 00007ffcb9e23328 BTRFS error (device loop0 state A): Transaction aborted (error -12) BTRFS: error (device loop0 state A ---truncated---

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21754"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-27T03:15:16Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix assertion failure when splitting ordered extent after transaction abort\n\nIf while we are doing a direct IO write a transaction abort happens, we\nmark all existing ordered extents with the BTRFS_ORDERED_IOERR flag (done\nat btrfs_destroy_ordered_extents()), and then after that if we enter\nbtrfs_split_ordered_extent() and the ordered extent has bytes left\n(meaning we have a bio that doesn\u0027t cover the whole ordered extent, see\ndetails at btrfs_extract_ordered_extent()), we will fail on the following\nassertion at btrfs_split_ordered_extent():\n\n   ASSERT(!(flags \u0026 ~BTRFS_ORDERED_TYPE_FLAGS));\n\nbecause the BTRFS_ORDERED_IOERR flag is set and the definition of\nBTRFS_ORDERED_TYPE_FLAGS is just the union of all flags that identify the\ntype of write (regular, nocow, prealloc, compressed, direct IO, encoded).\n\nFix this by returning an error from btrfs_extract_ordered_extent() if we\nfind the BTRFS_ORDERED_IOERR flag in the ordered extent. The error will\nbe the error that resulted in the transaction abort or -EIO if no\ntransaction abort happened.\n\nThis was recently reported by syzbot with the following trace:\n\n   FAULT_INJECTION: forcing a failure.\n   name failslab, interval 1, probability 0, space 0, times 1\n   CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller #0\n   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\n   Call Trace:\n    \u003cTASK\u003e\n    __dump_stack lib/dump_stack.c:94 [inline]\n    dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n    fail_dump lib/fault-inject.c:53 [inline]\n    should_fail_ex+0x3b0/0x4e0 lib/fault-inject.c:154\n    should_failslab+0xac/0x100 mm/failslab.c:46\n    slab_pre_alloc_hook mm/slub.c:4072 [inline]\n    slab_alloc_node mm/slub.c:4148 [inline]\n    __do_kmalloc_node mm/slub.c:4297 [inline]\n    __kmalloc_noprof+0xdd/0x4c0 mm/slub.c:4310\n    kmalloc_noprof include/linux/slab.h:905 [inline]\n    kzalloc_noprof include/linux/slab.h:1037 [inline]\n    btrfs_chunk_alloc_add_chunk_item+0x244/0x1100 fs/btrfs/volumes.c:5742\n    reserve_chunk_space+0x1ca/0x2c0 fs/btrfs/block-group.c:4292\n    check_system_chunk fs/btrfs/block-group.c:4319 [inline]\n    do_chunk_alloc fs/btrfs/block-group.c:3891 [inline]\n    btrfs_chunk_alloc+0x77b/0xf80 fs/btrfs/block-group.c:4187\n    find_free_extent_update_loop fs/btrfs/extent-tree.c:4166 [inline]\n    find_free_extent+0x42d1/0x5810 fs/btrfs/extent-tree.c:4579\n    btrfs_reserve_extent+0x422/0x810 fs/btrfs/extent-tree.c:4672\n    btrfs_new_extent_direct fs/btrfs/direct-io.c:186 [inline]\n    btrfs_get_blocks_direct_write+0x706/0xfa0 fs/btrfs/direct-io.c:321\n    btrfs_dio_iomap_begin+0xbb7/0x1180 fs/btrfs/direct-io.c:525\n    iomap_iter+0x697/0xf60 fs/iomap/iter.c:90\n    __iomap_dio_rw+0xeb9/0x25b0 fs/iomap/direct-io.c:702\n    btrfs_dio_write fs/btrfs/direct-io.c:775 [inline]\n    btrfs_direct_write+0x610/0xa30 fs/btrfs/direct-io.c:880\n    btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397\n    do_iter_readv_writev+0x600/0x880\n    vfs_writev+0x376/0xba0 fs/read_write.c:1050\n    do_pwritev fs/read_write.c:1146 [inline]\n    __do_sys_pwritev2 fs/read_write.c:1204 [inline]\n    __se_sys_pwritev2+0x196/0x2b0 fs/read_write.c:1195\n    do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n    entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   RIP: 0033:0x7f1281f85d29\n   RSP: 002b:00007f12819fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148\n   RAX: ffffffffffffffda RBX: 00007f1282176080 RCX: 00007f1281f85d29\n   RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000005\n   RBP: 00007f12819fe090 R08: 0000000000000000 R09: 0000000000000003\n   R10: 0000000000007000 R11: 0000000000000246 R12: 0000000000000002\n   R13: 0000000000000000 R14: 00007f1282176080 R15: 00007ffcb9e23328\n    \u003c/TASK\u003e\n   BTRFS error (device loop0 state A): Transaction aborted (error -12)\n   BTRFS: error (device loop0 state A\n---truncated---",
  "id": "GHSA-rv8h-hrgv-p5cw",
  "modified": "2025-02-27T03:34:05Z",
  "published": "2025-02-27T03:34:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21754"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d85f5c2dd91df6b5da454406756f463ba923b69"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ff88c2a742a7cbaa4d08507d864737d099b435a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8ea8db4216d1029527ab4666f730650419451e32"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/927b930f117bbae730a853c1dc43da8afe8380fa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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