{"id":"CVE-2026-45934","summary":"btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation","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---","modified":"2026-07-08T08:13:38.734924830Z","published":"2026-05-27T12:17:51.905Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45934.json","cna_assigner":"Linux"},"references":[{"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"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45934.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45934"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1b9845081633072c18f30d8cfd09c267adf0b109"},{"fixed":"7d4eadee7042d27fcea659fcdd738f463a7d2e70"},{"fixed":"156cac365e27a82b64ae510c5f463fd81f0265b1"},{"fixed":"b14c5e04bd0f722ed631845599d52d03fcae1bc1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45934.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.1.0"},{"fixed":"6.18.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45934.json"}}],"schema_version":"1.7.5"}