Messages in this thread | | | Date | Thu, 2 May 2013 11:25:12 -0700 | Subject | Re: [RFC PATCH] drivers: power: Add watchdog timer to catch drivers which lockup during suspend. | From | Colin Cross <> |
| |
On Thu, May 2, 2013 at 5:30 AM, Pavel Machek <pavel@ucw.cz> wrote: > Hi! > >> >> > do BUG which >> >> > dumps stack of current task >> >> > kills current task >> >> > >> >> > Current task may very well be idle task; in such case you kill the >> >> > machine. Sounds like you should be doing something else, like kill -9 >> >> > instead of BUG()? >> >> >> >> Not much else you can do, you are stuck part way into suspend with a >> >> driver's suspend callback half executed. All userspace tasks are >> >> frozen, and the suspend task is blocked indefinitely. >> > >> > Yes, there's better option. Attempt killing the [a]suspend task, >> > instead of killing the current task. >> >> That will leave you in a completely undefined state. If you just kill >> the task, you are likely to kill the synchronous suspend task, which >> is the task that would resume your drivers and unfreeze tasks. That >> will leave you with no userspace tasks running, and much of your >> hardware suspended. How is that a useful result? If you somehow > > So instead you kill random task? (BUG() from timer kills pretty much > random task, right?) > > If you want to do panic(), do panic().
At least on ARM a BUG() in an interrupt or softirq always results in a panic, but this can be switched to directly call panic.
| |