Messages in this thread | | | Date | Tue, 10 Nov 2015 01:29:39 +0100 | From | Andi Kleen <> | Subject | 4.3 serial driver crashes with console shortly after boot |
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Hi,
With 4.3 an x86 server is always crashing roughly a minute after boot in __uart_start/uart_tx_stopped. This is repeatable over multiple boots.
The back trace is flush_to_ldisc->n_tty_receive_buf2->n_tty_receive_buf_common-> commit_echoes-> uart_flush_chars->uart_start
It seems to follow a bad pointer here
ffffffff813bbdfa: f6 80 f4 01 00 00 01 testb $0x1,0x1f4(%rax) <--- ffffffff813bbe01: 74 01 je ffffffff813bbe04 <__uart_start.isra.1+0x24>
Unfortunately I don't have the contents of RAX which scrolled away, but since CR2 is 1f4 I suspect it's NUL.
It seems to depend on the order of the console=... arguments on the kernel command line. With console=tty0 console=ttyS0,115200n8 it crashes, but when reversing the options it does not crash.
-Andi -- ak@linux.intel.com -- Speaking for myself only.
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