Messages in this thread | | | Date | Thu, 22 May 2014 00:22:40 -0700 | From | Guenter Roeck <> | Subject | Re: pci: kernel crash in bus_find_device |
| |
On 05/22/2014 12:14 AM, Greg Kroah-Hartmann wrote: > On Wed, May 21, 2014 at 03:59:58PM -0700, Guenter Roeck wrote: >> On Wed, May 21, 2014 at 01:04:04PM -0700, Francesco Ruggeri wrote: >>> I have been using an x86 platform. >>> When I started working on it I got early crashes until I added the >>> check for p not NULL in >>> >>> +void bus_release_device(struct device *dev) >>> +{ >>> + struct device_private *p = dev->p; >>> + >>> + if (p && klist_node_attached(&p->knode_bus)) >>> + klist_put_last(&p->knode_bus); >>> +} >>> + >>> >>> Maybe on powerpc *p is overriden between device_del and device_release? >>> >>> Or maybe some of the BUG_ONs in the patch? The ones on knode_dead are >>> treated as WARN_ONs in the current klist code. >>> The one in BUG_ON(!klist_dec_and_del(n)); is new, and in my tests I >>> ran into it without the second patch (but only when I ran my module >>> and tests). >>> >> Hi Francesco, >> >> I replaced the BUG_ON with WARN_ON; still crashes. >> >> Anyway, the problem seems to be known. I found two related exchanges. >> >> [1] describes pretty much the same problem. I don't see if/where it was >> ever fixed, though. >> >> [2] is a patch to fix the problem. It did not apply cleanly to 3.14, >> so I had to make some adjustments in klist_iter_init_node. Resulting >> patch is below. With this patch, the problem is gone. It is not perfect, >> as it aborts the loop if it encounters a deleted kobject, but it is better >> than nothing. Unfortunately, the patch never made it upstream; no idea why. >> Copying the author and Greg to get additional feedback. >> >> Guenter >> >> [1] https://lkml.org/lkml/2008/10/26/79 >> [2] https://lkml.org/lkml/2012/4/16/218 > > 2 years ago? I have no idea what was up with that, sorry... >
Ok, but do you have comments on the patch itself in its current version ?
Guenter
| |