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SubjectPATCH: fix for soundblaster module oops at rmmod time (fwd)
[ I sent this to linux-sound yesterday. Nerijus Baliunas
<nerijus@users.sourceforge.net> 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:matze@camline.com phone: +49 8137 935-219

diff -ru linux/drivers/sound/sb_mixer.c linux-matze/drivers/sound/sb_mixer.c
--- linux/drivers/sound/sb_mixer.c Mon Sep 17 23:36:38 2001
+++ linux-matze/drivers/sound/sb_mixer.c Tue Sep 18 00:39:47 2001
@@ -748,6 +748,9 @@

void sb_mixer_unload(sb_devc *devc)
{
+ if (devc->my_mixerdev == -1)
+ return;
+
kfree(mixer_devs[devc->my_mixerdev]);
sound_unload_mixerdev(devc->my_mixerdev);
sbmixnum--;
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