NULL Pointer Dereference Affecting kernel-debuginfo package, versions <0:4.14.327-246.539.amzn2

Note: Versions mentioned in the description apply only to the upstream kernel-debuginfo package and not the kernel-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

serial: 8250_port: Check IRQ data before use

In case the leaf driver wants to use IRQ polling (irq = 0) and IIR register shows that an interrupt happened in the 8250 hardware the IRQ data can be NULL. In such a case we need to skip the wake event as we came to this path from the timer interrupt and quite likely system is already awake.

Without this fix we have got an Oops:

serial8250: ttyS0 at I/O 0x3f8 (irq = 0, base_baud = 115200) is a 16550A
...
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: 0010:serial8250_handle_irq+0x7c/0x240
Call Trace:
 ? serial8250_handle_irq+0x7c/0x240
 ? __pfx_serial8250_timeout+0x10/0x10

• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-52567
• https://git.kernel.org/stable/c/2b837f13a818f96304736453ac53b66a70aaa4f2
• https://git.kernel.org/stable/c/3345cc5f02f1fb4c4dcb114706f2210d879ab933
• https://git.kernel.org/stable/c/bf3c728e3692cc6d998874f0f27d433117348742
• https://git.kernel.org/stable/c/c334650150c29234b0923476f51573ae1b2f252a
• https://git.kernel.org/stable/c/cce7fc8b29961b64fadb1ce398dc5ff32a79643b
• https://git.kernel.org/stable/c/e14afa4450cb7e4cf93e993a765801203d41d014
• https://git.kernel.org/stable/c/e14f68a48fd445a083ac0750fafcb064df5f18f7
• https://git.kernel.org/stable/c/ee5732caaffba3a37e753fdb89b4958db9a61847