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GHSA-62RP-R79H-7Q8X

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-06-24 18:32
VLAI
Details

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

btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation

I have been observing a number of systems aborting at insert_dev_extents() in btrfs_create_pending_block_groups(). The following is a sample stack trace of such an abort coming from forced chunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this can theoretically happen to any DUP chunk allocation.

[81.801] ------------[ cut here ]------------ [81.801] BTRFS: Transaction aborted (error -17) [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319 [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014 [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs] [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282 [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000 [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0 [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007 [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000 [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000 [81.809] FS: 00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000 [81.809] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0 [81.810] Call Trace: [81.810] [81.810] __btrfs_end_transaction+0x3e/0x2b0 [btrfs] [81.811] btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs] [81.811] kernfs_fop_write_iter+0x15f/0x240 [81.812] vfs_write+0x264/0x500 [81.812] ksys_write+0x6c/0xe0 [81.812] do_syscall_64+0x66/0x770 [81.812] entry_SYSCALL_64_after_hwframe+0x76/0x7e [81.813] RIP: 0033:0x7fec6be66197 [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197 [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001 [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000 [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002 [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0 [81.817] [81.817] irq event stamp: 20039 [81.818] hardirqs last enabled at (20047): [] __up_console_sem+0x52/0x60 [81.818] hardirqs last disabled at (20056): [] __up_console_sem+0x37/0x60 [81.819] softirqs last enabled at (19470): [] __irq_exit_rcu+0x96/0xc0 [81.819] softirqs last disabled at (19463): [] __irq_exit_rcu+0x96/0xc0 [81.820] ---[ end trace 0000000000000000 ]--- [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists

Inspecting these aborts with drgn, I observed a pattern of overlapping chunk_maps. Note how stripe 1 of the first chunk overlaps in physical address with stripe 0 of the second chunk.

Physical Start Physical End Length Logical Type Stripe

0x0000000102500000 0x0000000142500000 1.0G 0x0000000641d00000 META|DUP 0/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000641d00000 META|DUP 1/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000601d00000 META|DUP 0/2 0x0000000182500000 0x00000001c2500000 1.0G 0x0000000601d00000 META|DUP 1/2

Now how could this possibly happen? All chunk allocation is ---truncated---

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-45934"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:09Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation\n\nI have been observing a number of systems aborting at\ninsert_dev_extents() in btrfs_create_pending_block_groups(). The\nfollowing is a sample stack trace of such an abort coming from forced\nchunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this\ncan theoretically happen to any DUP chunk allocation.\n\n  [81.801] ------------[ cut here ]------------\n  [81.801] BTRFS: Transaction aborted (error -17)\n  [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319\n  [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk\n  [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE\n  [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014\n  [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs]\n  [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282\n  [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000\n  [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0\n  [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007\n  [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000\n  [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000\n  [81.809] FS:  00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000\n  [81.809] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0\n  [81.810] Call Trace:\n  [81.810]  \u003cTASK\u003e\n  [81.810]  __btrfs_end_transaction+0x3e/0x2b0 [btrfs]\n  [81.811]  btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs]\n  [81.811]  kernfs_fop_write_iter+0x15f/0x240\n  [81.812]  vfs_write+0x264/0x500\n  [81.812]  ksys_write+0x6c/0xe0\n  [81.812]  do_syscall_64+0x66/0x770\n  [81.812]  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  [81.813] RIP: 0033:0x7fec6be66197\n  [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001\n  [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197\n  [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001\n  [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000\n  [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002\n  [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0\n  [81.817]  \u003c/TASK\u003e\n  [81.817] irq event stamp: 20039\n  [81.818] hardirqs last  enabled at (20047): [\u003cffffffff99a68302\u003e] __up_console_sem+0x52/0x60\n  [81.818] hardirqs last disabled at (20056): [\u003cffffffff99a682e7\u003e] __up_console_sem+0x37/0x60\n  [81.819] softirqs last  enabled at (19470): [\u003cffffffff999d2b46\u003e] __irq_exit_rcu+0x96/0xc0\n  [81.819] softirqs last disabled at (19463): [\u003cffffffff999d2b46\u003e] __irq_exit_rcu+0x96/0xc0\n  [81.820] ---[ end trace 0000000000000000 ]---\n  [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists\n\nInspecting these aborts with drgn, I observed a pattern of overlapping\nchunk_maps. Note how stripe 1 of the first chunk overlaps in physical\naddress with stripe 0 of the second chunk.\n\nPhysical Start     Physical End       Length       Logical            Type                 Stripe\n----------------------------------------------------------------------------------------------------\n0x0000000102500000 0x0000000142500000 1.0G         0x0000000641d00000 META|DUP             0/2\n0x0000000142500000 0x0000000182500000 1.0G         0x0000000641d00000 META|DUP             1/2\n0x0000000142500000 0x0000000182500000 1.0G         0x0000000601d00000 META|DUP             0/2\n0x0000000182500000 0x00000001c2500000 1.0G         0x0000000601d00000 META|DUP             1/2\n\nNow how could this possibly happen? All chunk allocation is\n---truncated---",
  "id": "GHSA-62rp-r79h-7q8x",
  "modified": "2026-06-24T18:32:28Z",
  "published": "2026-05-27T15:33:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45934"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/156cac365e27a82b64ae510c5f463fd81f0265b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7d4eadee7042d27fcea659fcdd738f463a7d2e70"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b14c5e04bd0f722ed631845599d52d03fcae1bc1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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