CVE-2024-26999

Summary

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

serial/pmac_zilog: 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 pmac_zilog as a serial console:

ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0

That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uart_port.

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

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 69a02273e288011b521ee7c1f3ab2c23fda633ceaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d679c816929d62af51c8e6d7fc0e165c9412d2f3affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ab86cf6f8d24e63e9aca23da5108af1aa5483928affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7a3bbe41efa55323b6ea3c35fa15941d4dbecdefaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < bbaafbb4651fede8d3c3881601ecaa4f834f9d3faffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 52aaf1ff14622a04148dbb9ccce6d9de5d534ea7affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ca09dfc3cfdf89e6af3ac24e1c6c0be5c575a729affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1be3226445362bfbf461c92a5bcdb1723f2e4907affected
LinuxLinux2.6.12affected
LinuxLinux0 < 2.6.12unaffected
LinuxLinux4.19.313 <= 4.19.*unaffected
LinuxLinux5.4.275 <= 5.4.*unaffected
LinuxLinux5.10.216 <= 5.10.*unaffected
LinuxLinux5.15.157 <= 5.15.*unaffected
LinuxLinux6.1.88 <= 6.1.*unaffected
LinuxLinux6.6.29 <= 6.6.*unaffected
LinuxLinux6.8.8 <= 6.8.*unaffected
LinuxLinux6.9 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References