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wcb4xxp: Prevent null pointer dereference on spanconfig

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In the rare case where spanconfig is called while there is pending data
on the hdlc channel, the hdlc_getbuf interrupt could try to read from
the hdlc buffer before the channel was fully setup. This could
potentially result in a null pointer dereference. This condition has
existed since the creation of the wcb4xxp driver.

Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
Signed-off-by: Shaun Ruffell <sruffell@digium.com>

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@10079 a0bf4364-ded3-4de4-8d8a-66a801d63aff
This commit is contained in:
Russ Meyerriecks 2011-07-22 17:56:07 +00:00
parent 00764f705c
commit 1813c9ad09
1 changed files with 3 additions and 0 deletions
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3
drivers/dahdi/wcb4xxp/base.c
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@ -2375,6 +2375,9 @@ b4xxp_chanconfig(struct file *file, struct dahdi_chan *chan, int sigtype)
if (alreadyrunning && bspan->sigchan) {
hdlc_stop(b4, fifo);
atomic_set(&bspan->hdlc_pending, 0);
bspan->sigactive = 0;
smp_mb();
bspan->sigchan = NULL;
}