CVE-2021-47622 scsi: ufs: Fix a deadlock in the error handler
A deadlock in the Linux kernel SCSI UFS error handler can cause a system hang, requiring a patch to fix the resource allocation logic.
- 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-2021-47622?
CVE-2021-47622 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Jul 2024. 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:
scsi: ufs: Fix a deadlock in the error handler
The following deadlock has been observed on a test setup:
- All tags allocated
- The SCSI error handler calls ufshcd_eh_host_reset_handler()
- ufshcd_eh_host_reset_handler() queues work that calls ufshcd_err_handler()
- ufshcd_err_handler() locks up as follows:
Workqueue: ufs_eh_wq_0 ufshcd_err_handler.cfi_jt Call trace: __switch_to+0x298/0x5d8 __schedule+0x6cc/0xa94 schedule+0x12c/0x298 blk_mq_get_tag+0x210/0x480 __blk_mq_alloc_request+0x1c8/0x284 blk_get_request+0x74/0x134 ufshcd_exec_dev_cmd+0x68/0x640 ufshcd_verify_dev_init+0x68/0x35c ufshcd_probe_hba+0x12c/0x1cb8 ufshcd_host_reset_and_restore+0x88/0x254 ufshcd_reset_and_restore+0xd0/0x354 ufshcd_err_handler+0x408/0xc58 process_one_work+0x24c/0x66c worker_thread+0x3e8/0xa4c kthread+0x150/0x1b4 ret_from_fork+0x10/0x30
Fix this lockup by making ufshcd_exec_dev_cmd() allocate a reserved request.
Weakness: CWE-667
Which versions are affected by CVE-2021-47622?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47622?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-47622 being exploited?
There is no known exploitation of CVE-2021-47622 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47622, GHSA-m484-77r4-h4vf, ROOT-OS-DEBIAN-11-CVE-2021-47622, UBUNTU-CVE-2021-47622.