On Tue, Jul 13, 2021 at 10:11:29PM +0100, Tom Murphy wrote:
> Hi Jonathan,
>
> On Tue, Jul 13, 2021 at 01:13:03PM +1000, Jonathan Gray wrote:
> > On Mon, Jul 12, 2021 at 06:22:36PM +0000, Tom Murphy wrote:
> > > I had firefox open (various tabs/windows) and was playing a 3D game
> > > (games/quakespasm) and after a random amount of time I got a hard lock up,
> > > but the second time it happened I was able to get into a ddb prompt. I've
> > > added the panic message and trace and dmesg.
> > >
> > > I don't have a serial console on this laptop so had to transcribe this by
> > > hand from a photo I took on my phone. (Is there an easier way to save
> > > these?)
> >
> > It is possible to get a trace out of a crash dump, see crash(8).
> > But yes serial or amt sol is easier.
>
> Thanks! I'll have a closer look at crash(8).
>
> > > panic: kernel diagnostic assertion "to_ticks >= 0" failed: file
> > > "/usr/src/sys/kern/kern_timeout.c", line 299
> > > Stopped at db_enter+0x10: popq %rbp
> > > TID PID UID PRFLAGS PFLAGS CPU COMMAND
> > > *395451 18070 0 0x14000 0x200 0K drmtskl
> > > 61931 46160 0 0x14000 0x200 2 drmwq
> > > 185485 53694 0 0x14000 0x200 1 drmwq
> > > 284820 77991 0 0x14000 0x200 3 drmwq
> > > db_enter() at db_enter+0x10
> > > panic(ffffffff81e5f243) at panic+0xbf
> > > __assert(ffffffff81ec940a,ffffffff81eb2a3e,12b,ffffffff81ec1795) at
> > > __assert+0x2b
> > > timeout_add(ffff800000bf0410,ffffffff) at timeout_add+0x1cc
> > > process_csb(ffff800000bf0000) at process_csb+0x38b
> > > execlists_submission_tasklet(ffff800000bf0000) at
> > > execlists_submission_tasklet+0x48
> > > tasklet_run(ffff800000bf03c0) at tasklet_run+0x44
> > > taskq_thread(ffff800000220f00) at taskq_thread+0x81
> > > end trace frame: 0x0, count: 7
> >
> > The timeout_add() call comes from i915_utils.c set_timer_ms()
> > mod_timer(t, jiffies + timeout ?: 1);
> >
> > can you try this patch?
> >
> > Index: sys/dev/pci/drm/include/linux/timer.h
> > ===================================================================
> > RCS file: /cvs/src/sys/dev/pci/drm/include/linux/timer.h,v
> > retrieving revision 1.6
> > diff -u -p -r1.6 timer.h
> > --- sys/dev/pci/drm/include/linux/timer.h 7 Jul 2021 02:38:36 -0000
> > 1.6
> > +++ sys/dev/pci/drm/include/linux/timer.h 13 Jul 2021 02:54:26 -0000
> > @@ -24,10 +24,20 @@
> > #include <sys/kernel.h>
> > #include <linux/ktime.h>
> >
> > -#define mod_timer(x, y) timeout_add((x), ((y) - jiffies))
> > #define del_timer_sync(x) timeout_del_barrier((x))
> > #define del_timer(x) timeout_del((x))
> > #define timer_pending(x) timeout_pending((x))
> > +
> > +static inline int
> > +mod_timer(struct timeout *to, unsigned long j)
> > +{
> > + int ticks = j - jiffies;
> > + if (ticks <= 0) {
> > + timeout_del(to);
> > + return timeout_add(to, 1);
> > + }
> > + return timeout_add(to, ticks);
> > +}
> >
> > static inline unsigned long
> > round_jiffies_up(unsigned long j)
>
> This patch seems to work for me. I did some pretty rigorous testing
> with it and attempted to recreate the same conditions that made it
> crash however I wasn't able to get the kernel panic so that is a good
> sign!
Thanks, I committed a slightly different version which does the test
without a type conversion.
Index: sys/dev/pci/drm/include/linux/timer.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/include/linux/timer.h,v
retrieving revision 1.6
diff -u -p -r1.6 timer.h
--- sys/dev/pci/drm/include/linux/timer.h 7 Jul 2021 02:38:36 -0000
1.6
+++ sys/dev/pci/drm/include/linux/timer.h 14 Jul 2021 04:49:03 -0000
@@ -24,10 +24,19 @@
#include <sys/kernel.h>
#include <linux/ktime.h>
-#define mod_timer(x, y) timeout_add((x), ((y) - jiffies))
#define del_timer_sync(x) timeout_del_barrier((x))
#define del_timer(x) timeout_del((x))
#define timer_pending(x) timeout_pending((x))
+
+static inline int
+mod_timer(struct timeout *to, unsigned long j)
+{
+ if (j <= jiffies) {
+ timeout_del(to);
+ return timeout_add(to, 1);
+ }
+ return timeout_add(to, j - jiffies);
+}
static inline unsigned long
round_jiffies_up(unsigned long j)
