Re: Latest net-next from GIT panic

quoted

This is why I suggested to replace the BUG() in another mail

So :

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h

index
f535779d9dc1dfe36934c2abba4e43d053ac5d6f..220cd12456754876edf2d3ef13195e82d70d5c74
100644

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -3331,7 +3331,15 @@ void netdev_run_todo(void);
   */
  static inline void dev_put(struct net_device *dev)
  {
-       this_cpu_dec(*dev->pcpu_refcnt);
+       int __percpu *pref = READ_ONCE(dev->pcpu_refcnt);
+
+       if (!pref) {
+               pr_err("no pcpu_refcnt on dev %p(%s) state %d dismantle

%d\n",
+                      dev, dev->name, dev->reg_state, dev->dismantle);
+               for (;;)
+                       cpu_relax();
+       }
+       this_cpu_dec(*pref);
  }
    /**

Thanks a lot Eric for the debug patch.

Pawel,

I want to confirm with you about the last good commit when you did bisection.
You mentioned:

And the last one

git bisect good
Bisecting: 1 revision left to test after this (roughly 1 step)
[1cfb71eeb12047bcdbd3e6730ffed66e810a0855] ipv6: take dst->__refcnt for
insertion into fib6 tree

With this have kernel panic same as always

git bisect bad
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[b838d5e1c5b6e57b10ec8af2268824041e3ea911] ipv4: mark DST_NOGC and
remove the operation of dst_free()

So it breaks right at:
[b838d5e1c5b6e57b10ec8af2268824041e3ea911] ipv4: mark DST_NOGC and
remove the operation of dst_free()
Right?
If you sync the image to one commit before the above one:
[9df16efadd2a8a82731dc76ff656c771e261827f] ipv4: call dst_hold_safe() properly
Does it crash?

And could you confirm that your config does not have any IPv6
addresses or routes configured?

Thanks.
Wei


6:03 +0200, Paweł Staszewski wrote:

quoted

quoted

Nit much more after adding this patch

https://bugzilla.kernel.org/attachment.cgi?id=258529

This is why I suggested to replace the BUG() in another mail

So :

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h

index
f535779d9dc1dfe36934c2abba4e43d053ac5d6f..220cd12456754876edf2d3ef13195e82d70d5c74
100644

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -3331,7 +3331,15 @@ void netdev_run_todo(void);
   */
  static inline void dev_put(struct net_device *dev)
  {
-       this_cpu_dec(*dev->pcpu_refcnt);
+       int __percpu *pref = READ_ONCE(dev->pcpu_refcnt);
+
+       if (!pref) {
+               pr_err("no pcpu_refcnt on dev %p(%s) state %d dismantle

%d\n",
+                      dev, dev->name, dev->reg_state, dev->dismantle);
+               for (;;)
+                       cpu_relax();
+       }
+       this_cpu_dec(*pref);
  }
    /**

Full panic

https://bugzilla.kernel.org/attachment.cgi?id=258531


I will change patch and apply but later today cause now cant use backup
router as testlab - Internet rush hours if something happens this will be
bed when second router will have bugged kernel :)