Messages in this thread | | | Subject | Re: Linux 2.6.17-rc2 - notifier chain problem? | From | Chandra Seetharaman <> | Date | Mon, 24 Apr 2006 16:01:57 -0700 |
| |
On Mon, 2006-04-24 at 15:03 -0700, Andrew Morton wrote: > Chandra Seetharaman <sekharan@us.ibm.com> wrote: > > > > Thanks for the steps. With that i was able to reproduce the problem and > > i found the bug. > > > > While i go ahead and generate the patch, i wanted to hear if my > > conclusion is correct. > > > > The problem is due to the fact that most notifier registrations > > incorrectly use __devinitdata to define the callback structure, as in: > > > > static struct notifier_block __devinitdata hrtimers_nb = { > > .notifier_call = hrtimer_cpu_notify, > > }; > > > > devinitdata'd data is not _expected to be available_ after the > > initialization(unless CONFIG_HOTPLUG is defined). > > > > I do not know how it was working until now :), anybody has a theory that > > can explain it (or my conclusion is wrong) ? > > That sounds right. There are several __devinitdata notifier_blocks in the > tree - please be sure to check them all.
Yes, I am covering all notifier blocks.
Another issue... many of the notifier callback functions are marked as init calls (__cpuinit, __devinit etc.,) as in:
static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
I am generating a separate patch to take care of those too. > > btw, it'd be pretty trivial to add runtime checking for this sort of thing: > > int addr_in_init_section(void *addr) > { > return addr >= __init_begin && addr < __init_end; > }
I will add this to kernel/sys.c, and put a BUG_ON to check for both the notifier block and the callback function.
BTW, which header file you want me to export this through ? > > (x86-specific) > (need to add __init_end to vmlinux.lds.S)
I see __init_end in arch/i386/kernel/vmlinux.lds.S.
> > then we could use that to check various things in various places... --
---------------------------------------------------------------------- Chandra Seetharaman | Be careful what you choose.... - sekharan@us.ibm.com | .......you may get it. ----------------------------------------------------------------------
- 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/
| |