UBUNTU-CVE-2024-26999
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.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
31 explicit affected versions
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81 explicit affected versions
13 explicit affected versions
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7 explicit affected versions
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10 explicit affected versions
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12 explicit affected versions
80 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
37 explicit affected versions
37 explicit affected versions
8 explicit affected versions
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38 explicit affected versions
167 explicit affected versions
40 explicit affected versions
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40 explicit affected versions
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97 explicit affected versions
52 explicit affected versions
121 explicit affected versions
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13 explicit affected versions
43 explicit affected versions
46 explicit affected versions
10 explicit affected versions
8 explicit affected versions
3 explicit affected versions
14 explicit affected versions
81 explicit affected versions
4 explicit affected versions
70 explicit affected versions
11 explicit affected versions
1 explicit affected versions
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2 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/1be3226445362bfbf461c92a5bcdb1723f2e4907
- https://git.kernel.org/stable/c/1be3226445362bfbf461c92a5bcdb1723f2e4907
- https://git.kernel.org/stable/c/52aaf1ff14622a04148dbb9ccce6d9de5d534ea7
- https://git.kernel.org/stable/c/7a3bbe41efa55323b6ea3c35fa15941d4dbecdef
- https://git.kernel.org/stable/c/bbaafbb4651fede8d3c3881601ecaa4f834f9d3f
- https://git.kernel.org/stable/c/ca09dfc3cfdf89e6af3ac24e1c6c0be5c575a729
- https://ubuntu.com/security/CVE-2024-26999
- https://ubuntu.com/security/notices/USN-6893-1
- https://ubuntu.com/security/notices/USN-6893-2
- https://ubuntu.com/security/notices/USN-6893-3
- https://ubuntu.com/security/notices/USN-6896-1
- https://ubuntu.com/security/notices/USN-6896-2
- https://ubuntu.com/security/notices/USN-6896-3
- https://ubuntu.com/security/notices/USN-6896-4
- https://ubuntu.com/security/notices/USN-6896-5
- https://ubuntu.com/security/notices/USN-6898-1
- https://ubuntu.com/security/notices/USN-6898-2
- https://ubuntu.com/security/notices/USN-6898-3
- https://ubuntu.com/security/notices/USN-6898-4
- https://ubuntu.com/security/notices/USN-6917-1
- https://ubuntu.com/security/notices/USN-6918-1
- https://ubuntu.com/security/notices/USN-6919-1
- https://ubuntu.com/security/notices/USN-6927-1
- https://ubuntu.com/security/notices/USN-7019-1
- https://www.cve.org/CVERecord?id=CVE-2024-26999