Re: [PATCH 1/1] of: properly check for error returned by fdt_get_name()

From: Frank Rowand
Date: Tue Apr 06 2021 - 16:30:07 EST


On 4/6/21 2:21 PM, Rob Herring wrote:
> On Sun, Apr 04, 2021 at 10:28:45PM -0500, frowand.list@xxxxxxxxx wrote:
>> From: Frank Rowand <frank.rowand@xxxxxxxx>
>>
>> fdt_get_name() returns error values via a parameter pointer
>> instead of in function return. Fix check for this error value
>> in populate_node() and callers of populate_node().
>>
>> Chasing up the caller tree showed callers of various functions
>> failing to initialize the value of pointer parameters that
>> can return error values. Initialize those values to NULL.
>>
>> The bug was introduced by
>> commit e6a6928c3ea1 ("of/fdt: Convert FDT functions to use libfdt")
>> but this patch can not be backported directly to that commit
>> because the relevant code has further been restructured by
>> commit dfbd4c6eff35 ("drivers/of: Split unflatten_dt_node()")
>>
>> The bug became visible by triggering a crash on openrisc with:
>> commit 79edff12060f ("scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9")
>> as reported in:
>> https://lore.kernel.org/lkml/20210327224116.69309-1-linux@xxxxxxxxxxxx/
>>
>> Fixes: commit 79edff12060f ("scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9")
>> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
>>
>> ---
>>
>> This patch papers over the unaligned pointer passed to
>> of_fdt_unflatten_tree() bug that Guenter reported in
>> https://lore.kernel.org/lkml/20210327224116.69309-1-linux@xxxxxxxxxxxx/
>>
>> I will create a separate patch to fix that problem.

Likely to be tomorrow (Wed 4/7).

-Frank

>
> Got an ETA for that?
>
> Rob
> .
>