cbcvebase.
CVE-2025-21820
published 2025-02-27

CVE-2025-21820: In the Linux kernel, the following vulnerability has been resolved: tty: xilinx_uartps: split sysrq handling lockdep detects the following circular locking…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.16%
5.8th percentile
In the Linux kernel, the following vulnerability has been resolved: tty: xilinx_uartps: split sysrq handling lockdep detects the following circular locking dependency: CPU 0 CPU 1 ========================== ============================ cdns_uart_isr() printk() uart_port_lock(port) console_lock() cdns_uart_console_write() if (!port->sysrq) uart_port_lock(port) uart_handle_break() port->sysrq = ... uart_handle_sysrq_char() printk() console_lock() The fixed commit attempts to avoid this situation by only taking the port lock in cdns_uart_console_write if port->sysrq unset. However, if (as shown above) cdns_uart_console_write runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock. Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock.

Affected

22 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.129-1 (bookworm)linux 6.1.129-1 (bookworm)
debianlinux-6.1< linux 6.1.129-1 (bookworm)linux 6.1.129-1 (bookworm)
linuxlinux
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < e22a97700901ba5e8bf8db68056a0d50f9440caee22a97700901ba5e8bf8db68056a0d50f9440cae
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < de5bd24197bd9ee37ec1e379a3d882bbd15c5065de5bd24197bd9ee37ec1e379a3d882bbd15c5065
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < 8ea0e7b3d7b8f2f0fc9db491ff22a0abe120801c8ea0e7b3d7b8f2f0fc9db491ff22a0abe120801c
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < 9b88a7c4584ba67267a051069b8abe44fc9595b29b88a7c4584ba67267a051069b8abe44fc9595b2
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < 4410dba9807a17a93f649a9f5870ceaf30a675a34410dba9807a17a93f649a9f5870ceaf30a675a3
linuxlinux>= 74ea66d4ca061a3cd4c0e924e51b60e924644852 < b06f388994500297bb91be60ffaf6825ecfd2afeb06f388994500297bb91be60ffaf6825ecfd2afe
linuxlinux_kernel>= 0 < 6.1.129-16.1.129-1
linuxlinux_kernel>= 0 < 6.12.15-16.12.15-1
linuxlinux_kernel>= 0 < 6.12.15-16.12.15-1
linuxlinux_kernel>= 0 < 5.15.0-140.1505.15.0-140.150
linuxlinux_kernel>= 0 < 6.8.0-64.676.8.0-64.67
linuxlinux_kernel>= 4.6 < 6.1.1296.1.129
linuxlinux_kernel>= 6.13 < 6.13.36.13.3
linuxlinux_kernel>= 6.2 < 6.6.786.6.78
linuxlinux_kernel>= 6.7 < 6.12.146.12.14
msrcazl3_kernel_6.6.64.2-9_on_azure_linux_3.0
msrcazl3_kernel_6.6.78.1-3_on_azure_linux_3.0
msrccbl2_kernel_5.15.179.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.182.1-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian5.5MEDIUM
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
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