CVE-2022-49176 bfq: fix use-after-free in bfq_dispatch_request
A use-after-free vulnerability in the Linux kernel's BFQ I/O scheduler allows attackers to cause denial of service or potentially execute code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49176?
CVE-2022-49176 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
bfq: fix use-after-free in bfq_dispatch_request
KASAN reports a use-after-free report when doing normal scsi-mq test
[69832.239032] ================================================================== [69832.241810] BUG: KASAN: use-after-free in bfq_dispatch_request+0x1045/0x44b0 [69832.243267] Read of size 8 at addr ffff88802622ba88 by task kworker/3:1H/155 [69832.244656] [69832.245007] CPU: 3 PID: 155 Comm: kworker/3:1H Not tainted 5.10.0-10295-g576c6382529e #8 [69832.246626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [69832.249069] Workqueue: kblockd blk_mq_run_work_fn [69832.250022] Call Trace: [69832.250541] dump_stack+0x9b/0xce [69832.251232] ? bfq_dispatch_request+0x1045/0x44b0 [69832.252243] print_address_description.constprop.6+0x3e/0x60 [69832.253381] ? __cpuidle_text_end+0x5/0x5 [69832.254211] ? vprintk_func+0x6b/0x120 [69832.254994] ? bfq_dispatch_request+0x1045/0x44b0 [69832.255952] ? bfq_dispatch_request+0x1045/0x44b0 [69832.256914] kasan_report.cold.9+0x22/0x3a [69832.257753] ? bfq_dispatch_request+0x1045/0x44b0 [69832.258755] check_memory_region+0x1c1/0x1e0 [69832.260248] bfq_dispatch_request+0x1045/0x44b0 [69832.261181] ? bfq_bfqq_expire+0x2440/0x2440 [69832.262032] ? blk_mq_delay_run_hw_queues+0xf9/0x170 [69832.263022] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.264011] ? blk_mq_sched_request_inserted+0x100/0x100 [69832.265101] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.266206] ? blk_mq_do_dispatch_ctx+0x570/0x570 [69832.267147] ? __switch_to+0x5f4/0xee0 [69832.267898] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.268946] __blk_mq_run_hw_queue+0xc0/0x270 [69832.269840] blk_mq_run_work_fn+0x51/0x60 [69832.278170] process_one_work+0x6d4/0xfe0 [69832.278984] worker_thread+0x91/0xc80 [69832.279726] ? __kthread_parkme+0xb0/0x110 [69832.280554] ? process_one_work+0xfe0/0xfe0 [69832.281414] kthread+0x32d/0x3f0 [69832.282082] ? kthread_park+0x170/0x170 [69832.282849] ret_from_fork+0x1f/0x30 [69832.283573] [69832.283886] Allocated by task 7725: [69832.284599] kasan_save_stack+0x19/0x40 [69832.285385] __kasan_kmalloc.constprop.2+0xc1/0xd0 [69832.286350] kmem_cache_alloc_node+0x13f/0x460 [69832.287237] bfq_get_queue+0x3d4/0x1140 [69832.287993] bfq_get_bfqq_handle_split+0x103/0x510 [69832.289015] bfq_init_rq+0x337/0x2d50 [69832.289749] bfq_insert_requests+0x304/0x4e10 [69832.290634] blk_mq_sched_insert_requests+0x13e/0x390 [69832.291629] blk_mq_flush_plug_list+0x4b4/0x760 [69832.292538] blk_flush_plug_list+0x2c5/0x480 [69832.293392] io_schedule_prepare+0xb2/0xd0 [69832.294209] io_schedule_timeout+0x13/0x80 [69832.295014] wait_for_common_io.constprop.1+0x13c/0x270 [69832.296137] submit_bio_wait+0x103/0x1a0 [69832.296932] blkdev_issue_discard+0xe6/0x160 [69832.297794] blk_ioctl_discard+0x219/0x290 [69832.298614] blkdev_common_ioctl+0x50a/0x1750 [69832.304715] blkdev_ioctl+0x470/0x600 [69832.305474] block_ioctl+0xde/0x120 [69832.306232] vfs_ioctl+0x6c/0xc0 [69832.306877] __se_sys_ioctl+0x90/0xa0 [69832.307629] do_syscall_64+0x2d/0x40 [69832.308362] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [69832.309382] [69832.309701] Freed by task 155: [69832.310328] kasan_save_stack+0x19/0x40 [69832.311121] kasan_set_track+0x1c/0x30 [69832.311868] kasan_set_free_info+0x1b/0x30 [69832.312699] __kasan_slab_free+0x111/0x160 [69832.313524] kmem_cache_free+0x94/0x460 [69832.314367] bfq_put_queue+0x582/0x940 [69832.315112] __bfq_bfqd_reset_in_service+0x166/0x1d0 [69832.317275] bfq_bfqq_expire+0xb27/0x2440 [69832.318084] bfq_dispatch_request+0x697/0x44b0 [69832.318991] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.319984] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.321087] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.322225] __blk_mq_run_hw_queue+0xc0/0x270 [69832.323114] blk_mq_run_work_fn+0x51/0x6 ---truncated---
Weakness: CWE-416
Which versions are affected by CVE-2022-49176?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49176?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2022-49176 being exploited?
There is no known exploitation of CVE-2022-49176 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49176, GHSA-95jr-p4jm-v55x, UBUNTU-CVE-2022-49176.