CVE-2023-53531 (GCVE-0-2023-53531)
Vulnerability from cvelistv5 – Published: 2025-10-01 11:46 – Updated: 2026-08-05 09:14
VLAI
EPSS
VEX
Title
null_blk: fix poll request timeout handling
Summary
In the Linux kernel, the following vulnerability has been resolved:
null_blk: fix poll request timeout handling
When doing io_uring benchmark on /dev/nullb0, it's easy to crash the
kernel if poll requests timeout triggered, as reported by David. [1]
BUG: kernel NULL pointer dereference, address: 0000000000000008
Workqueue: kblockd blk_mq_timeout_work
RIP: 0010:null_timeout_rq+0x4e/0x91
Call Trace:
? null_timeout_rq+0x4e/0x91
blk_mq_handle_expired+0x31/0x4b
bt_iter+0x68/0x84
? bt_tags_iter+0x81/0x81
__sbitmap_for_each_set.constprop.0+0xb0/0xf2
? __blk_mq_complete_request_remote+0xf/0xf
bt_for_each+0x46/0x64
? __blk_mq_complete_request_remote+0xf/0xf
? percpu_ref_get_many+0xc/0x2a
blk_mq_queue_tag_busy_iter+0x14d/0x18e
blk_mq_timeout_work+0x95/0x127
process_one_work+0x185/0x263
worker_thread+0x1b5/0x227
This is indeed a race problem between null_timeout_rq() and null_poll().
null_poll() null_timeout_rq()
spin_lock(&nq->poll_lock)
list_splice_init(&nq->poll_list, &list)
spin_unlock(&nq->poll_lock)
while (!list_empty(&list))
req = list_first_entry()
list_del_init()
...
blk_mq_add_to_batch()
// req->rq_next = NULL
spin_lock(&nq->poll_lock)
// rq->queuelist->next == NULL
list_del_init(&rq->queuelist)
spin_unlock(&nq->poll_lock)
Fix these problems by setting requests state to MQ_RQ_COMPLETE under
nq->poll_lock protection, in which null_timeout_rq() can safely detect
this race and early return.
Note this patch just fix the kernel panic when request timeout happen.
[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/
Severity
7.8 (High)
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
0a593fbbc245a85940ed34caa3aa1e4cb060c54b , < a0b4a0666beacfe8add9c71d8922475541dbae73
(git)
Affected: 0a593fbbc245a85940ed34caa3aa1e4cb060c54b , < a7cb2e709f2927cc3c76781df3e45de2381b3b9d (git) Affected: 0a593fbbc245a85940ed34caa3aa1e4cb060c54b , < 5a26e45edb4690d58406178b5a9ea4c6dcf2c105 (git) |
guessed | |
| Linux | Linux |
Affected:
5.16
Unaffected: 0 , < 5.16 (semver) Unaffected: 6.1.54 , ≤ 6.1.* (semver) Unaffected: 6.5.4 , ≤ 6.5.* (semver) Unaffected: 6.6 , ≤ * (original_commit_for_fix) |
guessed |
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: fix poll request timeout handling\n\nWhen doing io_uring benchmark on /dev/nullb0, it\u0027s easy to crash the\nkernel if poll requests timeout triggered, as reported by David. [1]\n\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nWorkqueue: kblockd blk_mq_timeout_work\nRIP: 0010:null_timeout_rq+0x4e/0x91\nCall Trace:\n ? null_timeout_rq+0x4e/0x91\n blk_mq_handle_expired+0x31/0x4b\n bt_iter+0x68/0x84\n ? bt_tags_iter+0x81/0x81\n __sbitmap_for_each_set.constprop.0+0xb0/0xf2\n ? __blk_mq_complete_request_remote+0xf/0xf\n bt_for_each+0x46/0x64\n ? __blk_mq_complete_request_remote+0xf/0xf\n ? percpu_ref_get_many+0xc/0x2a\n blk_mq_queue_tag_busy_iter+0x14d/0x18e\n blk_mq_timeout_work+0x95/0x127\n process_one_work+0x185/0x263\n worker_thread+0x1b5/0x227\n\nThis is indeed a race problem between null_timeout_rq() and null_poll().\n\nnull_poll()\t\t\t\tnull_timeout_rq()\n spin_lock(\u0026nq-\u003epoll_lock)\n list_splice_init(\u0026nq-\u003epoll_list, \u0026list)\n spin_unlock(\u0026nq-\u003epoll_lock)\n\n while (!list_empty(\u0026list))\n req = list_first_entry()\n list_del_init()\n ...\n blk_mq_add_to_batch()\n // req-\u003erq_next = NULL\n\t\t\t\t\tspin_lock(\u0026nq-\u003epoll_lock)\n\n\t\t\t\t\t// rq-\u003equeuelist-\u003enext == NULL\n\t\t\t\t\tlist_del_init(\u0026rq-\u003equeuelist)\n\n\t\t\t\t\tspin_unlock(\u0026nq-\u003epoll_lock)\n\nFix these problems by setting requests state to MQ_RQ_COMPLETE under\nnq-\u003epoll_lock protection, in which null_timeout_rq() can safely detect\nthis race and early return.\n\nNote this patch just fix the kernel panic when request timeout happen.\n\n[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/"
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: fix poll request timeout handling\n\nWhen doing io_uring benchmark on /dev/nullb0, it\u0027s easy to crash the\nkernel if poll requests timeout triggered, as reported by David. [1]\n\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nWorkqueue: kblockd blk_mq_timeout_work\nRIP: 0010:null_timeout_rq+0x4e/0x91\nCall Trace:\n ? null_timeout_rq+0x4e/0x91\n blk_mq_handle_expired+0x31/0x4b\n bt_iter+0x68/0x84\n ? bt_tags_iter+0x81/0x81\n __sbitmap_for_each_set.constprop.0+0xb0/0xf2\n ? __blk_mq_complete_request_remote+0xf/0xf\n bt_for_each+0x46/0x64\n ? __blk_mq_complete_request_remote+0xf/0xf\n ? percpu_ref_get_many+0xc/0x2a\n blk_mq_queue_tag_busy_iter+0x14d/0x18e\n blk_mq_timeout_work+0x95/0x127\n process_one_work+0x185/0x263\n worker_thread+0x1b5/0x227\n\nThis is indeed a race problem between null_timeout_rq() and null_poll().\n\nnull_poll()\t\t\t\tnull_timeout_rq()\n spin_lock(\u0026nq-\u003epoll_lock)\n list_splice_init(\u0026nq-\u003epoll_list, \u0026list)\n spin_unlock(\u0026nq-\u003epoll_lock)\n\n while (!list_empty(\u0026list))\n req = list_first_entry()\n list_del_init()\n ...\n blk_mq_add_to_batch()\n // req-\u003erq_next = NULL\n\t\t\t\t\tspin_lock(\u0026nq-\u003epoll_lock)\n\n\t\t\t\t\t// rq-\u003equeuelist-\u003enext == NULL\n\t\t\t\t\tlist_del_init(\u0026rq-\u003equeuelist)\n\n\t\t\t\t\tspin_unlock(\u0026nq-\u003epoll_lock)\n\nFix these problems by setting requests state to MQ_RQ_COMPLETE under\nnq-\u003epoll_lock protection, in which null_timeout_rq() can safely detect\nthis race and early return.\n\nNote this patch just fix the kernel panic when request timeout happen.\n\n[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/"
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"source": "Red Hat CSAF VEX",
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"title": "kernel: null_blk: fix poll request timeout handling",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53531.json",
"version": "3"
}
}
}
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