VULNERABILITY

Ubuntu: (Multiple Advisories) (CVE-2025-21820): Linux kernel vulnerabilities

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Ubuntu: (Multiple Advisories) (CVE-2025-21820): Linux kernel vulnerabilities

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
02/27/2025
Created
05/21/2025
Added
05/20/2025
Modified
05/22/2025

Description

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.

Solution(s)

  • ubuntu-upgrade-linux-image-5-15-0-1037-nvidia-tegra
  • ubuntu-upgrade-linux-image-5-15-0-1037-nvidia-tegra-rt
  • ubuntu-upgrade-linux-image-5-15-0-1066-gkeop
  • ubuntu-upgrade-linux-image-5-15-0-1076-ibm
  • ubuntu-upgrade-linux-image-5-15-0-1077-intel-iot-realtime
  • ubuntu-upgrade-linux-image-5-15-0-1078-nvidia
  • ubuntu-upgrade-linux-image-5-15-0-1078-nvidia-lowlatency
  • ubuntu-upgrade-linux-image-5-15-0-1079-intel-iotg
  • ubuntu-upgrade-linux-image-5-15-0-1080-kvm
  • ubuntu-upgrade-linux-image-5-15-0-1081-gke
  • ubuntu-upgrade-linux-image-5-15-0-1081-oracle
  • ubuntu-upgrade-linux-image-5-15-0-1083-gcp
  • ubuntu-upgrade-linux-image-5-15-0-1083-gcp-fips
  • ubuntu-upgrade-linux-image-5-15-0-1084-realtime
  • ubuntu-upgrade-linux-image-5-15-0-1089-azure
  • ubuntu-upgrade-linux-image-5-15-0-1089-azure-fips
  • ubuntu-upgrade-linux-image-5-15-0-140-fips
  • ubuntu-upgrade-linux-image-5-15-0-140-generic
  • ubuntu-upgrade-linux-image-5-15-0-140-generic-64k
  • ubuntu-upgrade-linux-image-5-15-0-140-generic-lpae
  • ubuntu-upgrade-linux-image-5-15-0-140-lowlatency
  • ubuntu-upgrade-linux-image-5-15-0-140-lowlatency-64k
  • ubuntu-upgrade-linux-image-6-11-0-1010-realtime
  • ubuntu-upgrade-linux-image-6-11-0-1013-raspi
  • ubuntu-upgrade-linux-image-6-11-0-1015-azure
  • ubuntu-upgrade-linux-image-6-11-0-1015-azure-fde
  • ubuntu-upgrade-linux-image-6-11-0-1015-gcp
  • ubuntu-upgrade-linux-image-6-11-0-1015-gcp-64k
  • ubuntu-upgrade-linux-image-6-11-0-1022-oem
  • ubuntu-upgrade-linux-image-6-11-0-26-generic
  • ubuntu-upgrade-linux-image-6-11-0-26-generic-64k
  • ubuntu-upgrade-linux-image-azure
  • ubuntu-upgrade-linux-image-azure-cvm
  • ubuntu-upgrade-linux-image-azure-fde
  • ubuntu-upgrade-linux-image-azure-fips
  • ubuntu-upgrade-linux-image-azure-lts-22-04
  • ubuntu-upgrade-linux-image-fips
  • ubuntu-upgrade-linux-image-gcp
  • ubuntu-upgrade-linux-image-gcp-64k
  • ubuntu-upgrade-linux-image-gcp-fips
  • ubuntu-upgrade-linux-image-gcp-lts-22-04
  • ubuntu-upgrade-linux-image-generic
  • ubuntu-upgrade-linux-image-generic-64k
  • ubuntu-upgrade-linux-image-generic-64k-hwe-24-04
  • ubuntu-upgrade-linux-image-generic-hwe-24-04
  • ubuntu-upgrade-linux-image-generic-lpae
  • ubuntu-upgrade-linux-image-gke
  • ubuntu-upgrade-linux-image-gke-5-15
  • ubuntu-upgrade-linux-image-gkeop
  • ubuntu-upgrade-linux-image-gkeop-5-15
  • ubuntu-upgrade-linux-image-ibm
  • ubuntu-upgrade-linux-image-intel-iot-realtime
  • ubuntu-upgrade-linux-image-intel-iotg
  • ubuntu-upgrade-linux-image-kvm
  • ubuntu-upgrade-linux-image-lowlatency
  • ubuntu-upgrade-linux-image-lowlatency-64k
  • ubuntu-upgrade-linux-image-lowlatency-64k-hwe-20-04
  • ubuntu-upgrade-linux-image-lowlatency-hwe-20-04
  • ubuntu-upgrade-linux-image-nvidia
  • ubuntu-upgrade-linux-image-nvidia-lowlatency
  • ubuntu-upgrade-linux-image-nvidia-tegra
  • ubuntu-upgrade-linux-image-nvidia-tegra-rt
  • ubuntu-upgrade-linux-image-oem-24-04b
  • ubuntu-upgrade-linux-image-oracle
  • ubuntu-upgrade-linux-image-oracle-lts-22-04
  • ubuntu-upgrade-linux-image-raspi
  • ubuntu-upgrade-linux-image-realtime
  • ubuntu-upgrade-linux-image-virtual
  • ubuntu-upgrade-linux-image-virtual-hwe-24-04

References

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