CVE-2024-26999: serial/pmac_zilog: Remove flawed mitigation for rx irq flood
In the Linux kernel, the following vulnerability has been resolved:
serial/pmaczilog: Remove flawed mitigation for rx irq flood
The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmaczilog as a serial console:
ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0
That's because the prerr() call in pmzreceivechars() results in pmzconsolewrite() attempting to lock a spinlock already locked in pmzinterrupt(). With CONFIGDEBUGSPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uartport.
Even when it's not fatal, the serial port rx function ceases to work. Also, the iteration limit doesn't play nicely with QEMU, as can be seen in the bug report linked below.
A web search for other reports of the error message "pmz: rx irq flood" didn't produce anything. So I don't think this code is needed any more. Remove it.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2024-26999?
CVE-2024-26999 is considered a serious vulnerability due to its potential to cause system crashes.
How do I fix CVE-2024-26999?
To fix CVE-2024-26999, upgrade to one of the patched Linux kernel versions, such as 5.10.223-1 or 6.12.11-1.
What systems are affected by CVE-2024-26999?
CVE-2024-26999 affects various versions of the Linux kernel including those found in Debian distributions.
Can CVE-2024-26999 lead to data loss?
Yes, exploitation of CVE-2024-26999 can lead to system instability and potential data loss.
Is CVE-2024-26999 actively exploited in the wild?
As of now, there is no public information confirming that CVE-2024-26999 is actively being exploited in the wild.