Re: locking issue (hardirq+softirq+user)

Arjan van de Ven wrote:
On Wed, 2006-12-20 at 14:35 +0100, Jiri Slaby wrote:
Hi!

an user still gets NMI watchdog warning, that the machine deadlocked.

have you tried enabling LOCKDEP ?

No, only PROVE_LOCKING, I apply him to turn this on too.

isr() /* i.e. hardirq context */
{
spin_lock(&lock);
...
spin_unlock(&lock);
}

this is ok if you are 100% sure that this never gets called in any other
way

It holds. Only in request_irq isr function name occurs.

timer() /* i.e. softirq context */
{
unsigned int f;
spin_lock_irqsave(&lock, f) /* stack shows, that it locks here */

this is a bug, the flags are an "unsigned long" not "unsigned int"!
It may do really bad stuff!

Aah, sorry, I misread the code, I saw flags, but it was port->flags;
board->flags, which is used in irq{save,restore} functions, is ulong.

thanks for the quick reply,
--
http://www.fi.muni.cz/~xslaby/ Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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