ghsa-8h6h-2w9h-vcg2
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
dm-bufio: fix sched in atomic context
If "try_verify_in_tasklet" is set for dm-verity, DM_BUFIO_CLIENT_NO_SLEEP is enabled for dm-bufio. However, when bufio tries to evict buffers, there is a chance to trigger scheduling in spin_lock_bh, the following warning is hit:
BUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2745 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 123, name: kworker/2:2 preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 4 locks held by kworker/2:2/123: #0: ffff88800a2d1548 ((wq_completion)dm_bufio_cache){....}-{0:0}, at: process_one_work+0xe46/0x1970 #1: ffffc90000d97d20 ((work_completion)(&dm_bufio_replacement_work)){....}-{0:0}, at: process_one_work+0x763/0x1970 #2: ffffffff8555b528 (dm_bufio_clients_lock){....}-{3:3}, at: do_global_cleanup+0x1ce/0x710 #3: ffff88801d5820b8 (&c->spinlock){....}-{2:2}, at: do_global_cleanup+0x2a5/0x710 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 2 UID: 0 PID: 123 Comm: kworker/2:2 Not tainted 6.16.0-rc3-g90548c634bd0 #305 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: dm_bufio_cache do_global_cleanup Call Trace: dump_stack_lvl+0x53/0x70 __might_resched+0x360/0x4e0 do_global_cleanup+0x2f5/0x710 process_one_work+0x7db/0x1970 worker_thread+0x518/0xea0 kthread+0x359/0x690 ret_from_fork+0xf3/0x1b0 ret_from_fork_asm+0x1a/0x30
That can be reproduced by:
veritysetup format --data-block-size=4096 --hash-block-size=4096 /dev/vda /dev/vdb SIZE=$(blockdev --getsz /dev/vda) dmsetup create myverity -r --table "0 $SIZE verity 1 /dev/vda /dev/vdb 4096 4096 1 sha256 1 try_verify_in_tasklet" mount /dev/dm-0 /mnt -o ro echo 102400 > /sys/module/dm_bufio/parameters/max_cache_size_bytes [read files in /mnt]
{
"affected": [],
"aliases": [
"CVE-2025-38496"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-28T12:15:31Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-bufio: fix sched in atomic context\n\nIf \"try_verify_in_tasklet\" is set for dm-verity, DM_BUFIO_CLIENT_NO_SLEEP\nis enabled for dm-bufio. However, when bufio tries to evict buffers, there\nis a chance to trigger scheduling in spin_lock_bh, the following warning\nis hit:\n\nBUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2745\nin_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 123, name: kworker/2:2\npreempt_count: 201, expected: 0\nRCU nest depth: 0, expected: 0\n4 locks held by kworker/2:2/123:\n #0: ffff88800a2d1548 ((wq_completion)dm_bufio_cache){....}-{0:0}, at: process_one_work+0xe46/0x1970\n #1: ffffc90000d97d20 ((work_completion)(\u0026dm_bufio_replacement_work)){....}-{0:0}, at: process_one_work+0x763/0x1970\n #2: ffffffff8555b528 (dm_bufio_clients_lock){....}-{3:3}, at: do_global_cleanup+0x1ce/0x710\n #3: ffff88801d5820b8 (\u0026c-\u003espinlock){....}-{2:2}, at: do_global_cleanup+0x2a5/0x710\nPreemption disabled at:\n[\u003c0000000000000000\u003e] 0x0\nCPU: 2 UID: 0 PID: 123 Comm: kworker/2:2 Not tainted 6.16.0-rc3-g90548c634bd0 #305 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nWorkqueue: dm_bufio_cache do_global_cleanup\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x53/0x70\n __might_resched+0x360/0x4e0\n do_global_cleanup+0x2f5/0x710\n process_one_work+0x7db/0x1970\n worker_thread+0x518/0xea0\n kthread+0x359/0x690\n ret_from_fork+0xf3/0x1b0\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\n\nThat can be reproduced by:\n\n veritysetup format --data-block-size=4096 --hash-block-size=4096 /dev/vda /dev/vdb\n SIZE=$(blockdev --getsz /dev/vda)\n dmsetup create myverity -r --table \"0 $SIZE verity 1 /dev/vda /dev/vdb 4096 4096 \u003cdata_blocks\u003e 1 sha256 \u003croot_hash\u003e \u003csalt\u003e 1 try_verify_in_tasklet\"\n mount /dev/dm-0 /mnt -o ro\n echo 102400 \u003e /sys/module/dm_bufio/parameters/max_cache_size_bytes\n [read files in /mnt]",
"id": "GHSA-8h6h-2w9h-vcg2",
"modified": "2025-07-28T12:30:36Z",
"published": "2025-07-28T12:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38496"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3edfdb1d4ef81320dae0caa40bc24baf8c1bbb86"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/469a39a33a9934af157299bf11c58f6e6cb53f85"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/68860d1ade385eef9fcdbf6552f061283091fdb8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b1bf1a782fdf5c482215c0c661b5da98b8e75773"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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