linux-kernel - Re: OF-related boot crash in 3.3.0-rc3-00188-g3ec1e88

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Date:	Mon, 13 Feb 2012 14:46:23 -0700
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Meelis Roos <mroos@...ux.ee>
Cc:	Rob Herring <rob.herring@...xeda.com>, sparclinux@...r.kernel.org,
	Linux Kernel list <linux-kernel@...r.kernel.org>
Subject: Re: OF-related boot crash in 3.3.0-rc3-00188-g3ec1e88

On Mon, Feb 13, 2012 at 11:20:36AM +0200, Meelis Roos wrote:
> > Try the following patch.  I suspect the new of_alias_scan() isn't careful
> > enough about which properties it dereferences:
> > 
> > ---
> > 
> > diff --git a/drivers/of/base.c b/drivers/of/base.c
> > index 133908a..9188caa 100644
> > --- a/drivers/of/base.c
> > +++ b/drivers/of/base.c
> > @@ -1174,6 +1174,10 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
> >  		    !strcmp(pp->name, "linux,phandle"))
> >  			continue;
> >  
> > +		/* Check for null value or non-strings (no null termination) */
> > +		if (!pp->value || strnlen(pp->value, pp->length) == pp->length)
> > +			continue;
> > +
> >  		np = of_find_node_by_path(pp->value);
> >  		if (!np)
> >  			continue;
> > 
> 
> Yes, it probably gets past this problem but oopses in a different place:
> 
> [    0.000000] PROMLIB: Sun IEEE Boot Prom 'OBP 3.2.30 2002/10/25 14:03'
> [    0.000000] PROMLIB: Root node compatible: 
> [    0.000000] Initializing cgroup subsys cpu
> [    0.000000] Linux version 3.3.0-rc3-00188-g3ec1e88-dirty (mroos@...vits) (gcc version 4.6.2 (Debian 42
> [    0.000000] debug: ignoring loglevel setting.
> [    0.000000] bootconsole [earlyprom0] enabled
> [    0.000000] ARCH: SUN4U
> [    0.000000] Ethernet address: 08:00:20:b6:ee:e2
> [    0.000000] Kernel: Using 4 locked TLB entries for main kernel image.
> [    0.000000] Remapping the kernel... done.
> [    0.000000] Unable to handle kernel NULL pointer dereference
> [    0.000000] tsk->{mm,active_mm}->context = 0000000000000000
> [    0.000000] tsk->{mm,active_mm}->pgd = fffff800008c77d0
> [    0.000000]               \|/ ____ \|/
> [    0.000000]               "@'/ .. \`@"
> [    0.000000]               /_| \__/ |_\
> [    0.000000]                  \__U_/
> [    0.000000] swapper(0): Oops [#1]
> [    0.000000] TSTATE: 0000000080e01606 TPC: 0000000000645810 TNPC: 0000000000645814 Y: 00000037    Not d
> [    0.000000] TPC: <of_find_node_by_phandle+0x30/0x60>

Ugh; that looks bad.  If it failed there, then the global device node list
is corrupted.  I hate to ask you this, but would you be able to git bisect to
narrow down the commit that causes the problem?

g.
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