On Sun, 3 Nov 2002, Davide Libenzi wrote:
| On Sun, 3 Nov 2002, William Lee Irwin III wrote:
|
| > On Sun, 3 Nov 2002, William Lee Irwin III wrote:
| > [...]
| > >> The only action taken is printk() and dump_stack(). No arch code has
| > >> been futzed with to provide irq tainting yet. Looks like a good way
| > >> to shake out lurking bugs to me (somewhat like may_sleep() etc.).
| >
| > On Sun, Nov 03, 2002 at 04:15:46PM -0800, Davide Libenzi wrote:
| > > Wouldn't it be interesting to keep a ( per task ) list of acquired
| > > spinlocks to be able to diagnose cross locks in case of stall ?
| > > ( obviously under CONFIG_DEBUG_SPINLOCK )
| >
| > That would appear to require cycle detection, but it sounds like a
| > potential breakthrough usage of graph algorithms in the kernel.
| > (I've always been told graph algorithms would come back to haunt me.)
| > Or maybe not, deadlock detection has been done before.
| >
| > A separate patch/feature/whatever for deadlock detection could do that
| > nicely, though. What I've presented here is meant only to flag far more
| > trivial errors with interrupt enablement/disablement than the full
| > deadlock detection problem.
|
| It's not realy a graph Bill. Each task has a list of acquired locks (
| by address ). You keep __LINE__ and __FILE__ with you list items. When
| there's a deadlock you'll have somewhere :
|
| TSK#N TSK#M
| -------------
| ... ...
| LCK#I LCK#J
| ... ...
| -> LCK#J LCK#I
|
| Then with a SysReq key you dump the list of acquired locks for each task
| who's spinning for a lock. IMO it might be usefull ...
What's a task in this context? Are we (you) talking about
kernel threads/drivers etc. or userspace?
-- ~Randy "I'm a healthy mushroom."- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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