PATCH: fix for soundblaster module oops at rmmod time (fwd)

[Matthias Hanisch]

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[ I sent this to linux-sound yesterday. Nerijus Baliunas
  <[e-mail]> asked me to forward this also to
  linux-kernel. So here it is.
] 

Hi!

Soundblaster module in version 2.4.10-pre12 and many (pre-)patches before
oopsed in sb_dsp_unload at the module deletion phase.

Loading the module reports

Sep 17 23:08:05 pingu kernel: <Sound Blaster (8 BIT/MONO ONLY) (2.01)> at
0x220 irq 5 dma 1>

so sb_mixer_init() is not called, because devc->major == 2.

Problem is that at "module deletion time", the call to sb_mixer_unload()
is unconditional and a

        kfree(mixer_devs[devc->my_mixerdev]);

is not very healthy if devc->my_mixerdev == -1 (the initial value).

This kfree() call without checking the array index got introduced in
2.4.8, sound_unload_mixerdev() which is called after kfree() contains a
check for devc->my_mixerdev != -1.

The attached patch cures this, it just introduces this check. It should
apply to any recent kernel.

Regards,

        Matze

-- 
Matthias Hanisch    mailto:[e-mail]    phone: [phone]

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