Re: 2.6.13-rc1-git2 Oops on rmmod serial_core

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Sat, Jul 02, 2005 at 06:57:54AM +0000, Kenneth Parrish wrote:
> The serial support code newly allows selecting the max number of serial
> ports. This computer has one s-port so i typed '1'.
> 
>  config SERIAL_8250_NR_UARTS
>  int "Maximum number of 8250/16550 serial ports"
>  depends on SERIAL_8250
>  default "4"
>  help
>  Set this to the number of serial ports you want the driver
>  to support.  This includes any ports discovered via ACPI or
>  PCI enumeration and any ports that may be added at run-time
>  via hot-plug, or any ISA multi-port serial cards.
> 
> I found the value needs to be at least '4' or we oops at rmmod
> serial_core.  2.6.13-rc1-git2 kernels with values from one through four
> were tested.

It's actually worse than that.  If you set it to less than 4 on an x86
PC, it'll stamp over memory.  All is not lost though - it's fixed in:

http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=44454bcdb90532b372c74e3546043d8a3a468939

I'd advise people _not_ to run -git2.  If they do and they see any
oddities, please don't bother reporting them unless you can reproduce
them with a later version or with this set to at least '4'.  This
problem can cause oopses in other parts of the kernel.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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