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kbdfs: send interrupt note in separate proc to prevent potential deadlock

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This commit is contained in:
cinap_lenrek 2012-11-09 17:39:35 +01:00
parent 663aff7fb2
commit 0df3f94ecd
1 changed files with 20 additions and 2 deletions
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22
sys/src/cmd/aux/kbdfs/kbdfs.c
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@ -113,6 +113,7 @@ Channel *runechan; /* chan(Rune) */
Channel *conschan; /* chan(char*) */
Channel *kbdchan; /* chan(char*) */
Channel *intchan; /* chan(int) */
/*
* The codes at 0x79 and 0x7b are produced by the PFU Happy Hacking keyboard.
@ -543,6 +544,21 @@ Forward:
}
}
/*
* Need to do this in a separate proc because if process we're interrupting
* is dying and trying to print tombstone, kernel is blocked holding p->debug lock.
*/
void
intrproc(void *)
{
threadsetname("intrproc");
for(;;){
if(recv(intchan, nil) > 0)
write(notefd, "interrupt", 9);
}
}
/*
* Cook lines for cons
*/
@ -565,9 +581,8 @@ lineproc(void *aux)
recv(cook, &r);
switch(r){
case Kdel:
if(notefd < 0)
if(nbsend(intchan, &notefd) <= 0)
continue;
write(notefd, "interrupt", 9);
/* no break */
case '\0': /* flush */
nr = 0;
@ -711,6 +726,8 @@ ctlproc(void *)
proccreate(scanproc, nil, STACK); /* scanfd -> keychan */
if(consfd >= 0)
proccreate(consproc, nil, STACK); /* consfd -> runechan */
if(notefd >= 0)
proccreate(intrproc, nil, STACK); /* intchan -> notefd */
threadcreate(keyproc, nil, STACK); /* keychan -> rawchan, kbdchan */
threadcreate(runeproc, nil, STACK); /* rawchan -> runechan */
@ -1382,6 +1399,7 @@ threadmain(int argc, char** argv)
runechan = chancreate(sizeof(Rune), 32);
conschan = chancreate(sizeof(char*), 16);
kbdchan = chancreate(sizeof(char*), 16);
intchan = chancreate(sizeof(int), 0);
elevate();
procrfork(ctlproc, nil, STACK, RFNAMEG|RFNOTEG);