GHSA-HRJH-VPGF-4C95
Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-17 18:31In the Linux kernel, the following vulnerability has been resolved:
btrfs: defrag: fix deadlock between defrag and delalloc space reservation
While running fsstress with autodefrag and flushoncommit, hit a deadlock due to the fact that defrag reserves delalloc space while it's holding dirty and locked folios, besides the extent range lock. The stack traces are the following:
[958.624] task:kworker/u50:3 state:D stack:0 pid:20365 tgid:20365 ppid:2 task_flags:0x4208060 flags:0x00080000 [958.626] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] [958.627] Call Trace: [958.628] [958.628] __schedule+0x4be/0x10f0 [958.629] ? preempt_count_add+0x69/0xa0 [958.630] schedule+0x26/0xd0 [958.631] wait_current_trans+0x102/0x160 [btrfs] [958.632] ? __pfx_autoremove_wake_function+0x10/0x10 [958.633] start_transaction+0x374/0x900 [btrfs] [958.634] btrfs_commit_current_transaction+0x1d/0x70 [btrfs] [958.635] flush_space+0xca/0x5e0 [btrfs] [958.636] ? raw_spin_unlock+0x15/0x30 [958.637] ? btrfs_reduce_alloc_profile+0x8c/0x190 [btrfs] [958.639] ? _raw_spin_unlock+0x15/0x30 [958.640] ? calc_available_free_space.isra.0+0x6f/0x110 [btrfs] [958.641] do_async_reclaim_metadata_space+0x84/0x190 [btrfs] [958.642] btrfs_async_reclaim_metadata_space+0x64/0x80 [btrfs] [958.644] process_one_work+0x19d/0x3a0 [958.644] worker_thread+0x1c4/0x330 [958.645] ? __pfx_worker_thread+0x10/0x10 [958.646] kthread+0xfc/0x130 [958.647] ? __pfx_kthread+0x10/0x10 [958.648] ret_from_fork+0x1f7/0x2c0 [958.648] ? __pfx_kthread+0x10/0x10 [958.649] ret_from_fork_asm+0x1a/0x30 [958.650] [958.651] task:kworker/u49:7 state:D stack:0 pid:52990 tgid:52990 ppid:2 task_flags:0x4208060 flags:0x00080000 [958.653] Workqueue: writeback wb_workfn (flush-btrfs-334) [958.655] Call Trace: [958.655] [958.656] __schedule+0x4be/0x10f0 [958.657] ? __blk_flush_plug+0xe9/0x140 [958.658] schedule+0x26/0xd0 [958.658] io_schedule+0x42/0x70 [958.659] folio_wait_bit_common+0x12b/0x330 [958.660] ? folio_wait_bit_common+0x100/0x330 [958.662] ? __pfx_wake_page_function+0x10/0x10 [958.663] extent_write_cache_pages+0x599/0x830 [btrfs] [958.664] ? acpi_fwnode_get_reference_args+0x1fa/0x270 [958.665] btrfs_writepages+0x77/0x130 [btrfs] [958.666] ? __pfx_end_bbio_data_write+0x10/0x10 [btrfs] [958.667] do_writepages+0xc6/0x160 [958.668] __writeback_single_inode+0x42/0x310 [958.669] writeback_sb_inodes+0x231/0x570 [958.670] wb_writeback+0x8a/0x340 [958.671] wb_workfn+0xbf/0x450 [958.672] ? finish_task_switch.isra.0+0xc1/0x350 [958.673] process_one_work+0x19d/0x3a0 [958.673] worker_thread+0x1c4/0x330 [958.674] ? __pfx_worker_thread+0x10/0x10 [958.675] kthread+0xfc/0x130 [958.676] ? __pfx_kthread+0x10/0x10 [958.676] ret_from_fork+0x1f7/0x2c0 [958.677] ? __pfx_kthread+0x10/0x10 [958.678] ret_from_fork_asm+0x1a/0x30 [958.679] [958.679] task:btrfs-cleaner state:D stack:0 pid:296750 tgid:296750 ppid:2 task_flags:0x208040 flags:0x00080000 [958.681] Call Trace: [958.682] [958.682] __schedule+0x4be/0x10f0 [958.683] schedule+0x26/0xd0 [958.684] handle_reserve_ticket+0x1b9/0x2c0 [btrfs] [958.685] ? __pfx_autoremove_wake_function+0x10/0x10 [958.686] reserve_bytes+0x283/0x4c0 [btrfs] [958.687] btrfs_reserve_metadata_bytes+0x18/0xb0 [btrfs] [958.688] btrfs_delalloc_reserve_metadata+0x121/0x320 [btrfs] [958.690] btrfs_delalloc_reserve_space+0x46/0xb0 [btrfs] [958.691] btrfs_defrag_file+0x903/0x1110 [btrfs] [958.692] btrfs_run_defrag_inodes+0x334/0x430 [btrfs] [958.694] cleaner_kthread+0x97/0x1c0 [btrfs] [958.694] ? __pfx_cleaner_kthread+0x10/0x10 [btrfs] [958.696] kthread+0xfc/0x130 [958.696] ? __pfx_kthread+0x10/0x10 [958.697] ret ---truncated---
{
"affected": [],
"aliases": [
"CVE-2026-90265"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-17T17:17:23Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: defrag: fix deadlock between defrag and delalloc space reservation\n\nWhile running fsstress with autodefrag and flushoncommit, hit a deadlock\ndue to the fact that defrag reserves delalloc space while it\u0027s holding\ndirty and locked folios, besides the extent range lock. The stack traces\nare the following:\n\n [958.624] task:kworker/u50:3 state:D stack:0 pid:20365 tgid:20365 ppid:2 task_flags:0x4208060 flags:0x00080000\n [958.626] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]\n [958.627] Call Trace:\n [958.628] \u003cTASK\u003e\n [958.628] __schedule+0x4be/0x10f0\n [958.629] ? preempt_count_add+0x69/0xa0\n [958.630] schedule+0x26/0xd0\n [958.631] wait_current_trans+0x102/0x160 [btrfs]\n [958.632] ? __pfx_autoremove_wake_function+0x10/0x10\n [958.633] start_transaction+0x374/0x900 [btrfs]\n [958.634] btrfs_commit_current_transaction+0x1d/0x70 [btrfs]\n [958.635] flush_space+0xca/0x5e0 [btrfs]\n [958.636] ? _raw_spin_unlock+0x15/0x30\n [958.637] ? btrfs_reduce_alloc_profile+0x8c/0x190 [btrfs]\n [958.639] ? _raw_spin_unlock+0x15/0x30\n [958.640] ? calc_available_free_space.isra.0+0x6f/0x110 [btrfs]\n [958.641] do_async_reclaim_metadata_space+0x84/0x190 [btrfs]\n [958.642] btrfs_async_reclaim_metadata_space+0x64/0x80 [btrfs]\n [958.644] process_one_work+0x19d/0x3a0\n [958.644] worker_thread+0x1c4/0x330\n [958.645] ? __pfx_worker_thread+0x10/0x10\n [958.646] kthread+0xfc/0x130\n [958.647] ? __pfx_kthread+0x10/0x10\n [958.648] ret_from_fork+0x1f7/0x2c0\n [958.648] ? __pfx_kthread+0x10/0x10\n [958.649] ret_from_fork_asm+0x1a/0x30\n [958.650] \u003c/TASK\u003e\n [958.651] task:kworker/u49:7 state:D stack:0 pid:52990 tgid:52990 ppid:2 task_flags:0x4208060 flags:0x00080000\n [958.653] Workqueue: writeback wb_workfn (flush-btrfs-334)\n [958.655] Call Trace:\n [958.655] \u003cTASK\u003e\n [958.656] __schedule+0x4be/0x10f0\n [958.657] ? __blk_flush_plug+0xe9/0x140\n [958.658] schedule+0x26/0xd0\n [958.658] io_schedule+0x42/0x70\n [958.659] folio_wait_bit_common+0x12b/0x330\n [958.660] ? folio_wait_bit_common+0x100/0x330\n [958.662] ? __pfx_wake_page_function+0x10/0x10\n [958.663] extent_write_cache_pages+0x599/0x830 [btrfs]\n [958.664] ? acpi_fwnode_get_reference_args+0x1fa/0x270\n [958.665] btrfs_writepages+0x77/0x130 [btrfs]\n [958.666] ? __pfx_end_bbio_data_write+0x10/0x10 [btrfs]\n [958.667] do_writepages+0xc6/0x160\n [958.668] __writeback_single_inode+0x42/0x310\n [958.669] writeback_sb_inodes+0x231/0x570\n [958.670] wb_writeback+0x8a/0x340\n [958.671] wb_workfn+0xbf/0x450\n [958.672] ? finish_task_switch.isra.0+0xc1/0x350\n [958.673] process_one_work+0x19d/0x3a0\n [958.673] worker_thread+0x1c4/0x330\n [958.674] ? __pfx_worker_thread+0x10/0x10\n [958.675] kthread+0xfc/0x130\n [958.676] ? __pfx_kthread+0x10/0x10\n [958.676] ret_from_fork+0x1f7/0x2c0\n [958.677] ? __pfx_kthread+0x10/0x10\n [958.678] ret_from_fork_asm+0x1a/0x30\n [958.679] \u003c/TASK\u003e\n [958.679] task:btrfs-cleaner state:D stack:0 pid:296750 tgid:296750 ppid:2 task_flags:0x208040 flags:0x00080000\n [958.681] Call Trace:\n [958.682] \u003cTASK\u003e\n [958.682] __schedule+0x4be/0x10f0\n [958.683] schedule+0x26/0xd0\n [958.684] handle_reserve_ticket+0x1b9/0x2c0 [btrfs]\n [958.685] ? __pfx_autoremove_wake_function+0x10/0x10\n [958.686] reserve_bytes+0x283/0x4c0 [btrfs]\n [958.687] btrfs_reserve_metadata_bytes+0x18/0xb0 [btrfs]\n [958.688] btrfs_delalloc_reserve_metadata+0x121/0x320 [btrfs]\n [958.690] btrfs_delalloc_reserve_space+0x46/0xb0 [btrfs]\n [958.691] btrfs_defrag_file+0x903/0x1110 [btrfs]\n [958.692] btrfs_run_defrag_inodes+0x334/0x430 [btrfs]\n [958.694] cleaner_kthread+0x97/0x1c0 [btrfs]\n [958.694] ? __pfx_cleaner_kthread+0x10/0x10 [btrfs]\n [958.696] kthread+0xfc/0x130\n [958.696] ? __pfx_kthread+0x10/0x10\n [958.697] ret_\n---truncated---",
"id": "GHSA-hrjh-vpgf-4c95",
"modified": "2026-09-17T18:31:58Z",
"published": "2026-09-17T18:31:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90265"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a9701dd06e82c345fe70debdf8835b7eb5000c59"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ac916391e1c70801649f7d6f85014f687983bc33"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ba02eab28041f9a4bbe9fc90c7249644fef6de0f"
}
],
"schema_version": "1.4.0",
"severity": []
}
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