Re: [PATCH] wifi: brcmfmac: Check the return value of of_property_read_string_index

["Stefan Dösinger" <stefan@codeweavers.com>]

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Am Montag, 6. Januar 2025, 14:02:17 Ostafrikanische Zeit schrieb Arend van 
Spriel:
> On 1/6/2025 11:37 AM, Stefan Dösinger wrote:
> > Somewhen between 6.10 and 6.11 the driver started to crash on my
> > MacBookPro14,3. The property doesn't exist and 'tmp' remains
> > uninitialized, so we pass a random pointer to devm_kstrdup().
> 
> By the looks of it this is an intel-based platform. Is that correct? So
> does it have a devicetree? I would expect the root node find to fail,
> but apparently is does not. Strange though that root node does not have
> a compatible property. Anyway, the analysis looks sane so ...

Yes, this is an Intel based MacBook Pro - the 2017 version.

I was curious about the same thing and tried to find out where it expects to 
get those properties from. I didn't find a definitive answer and concluded 
that it reads the properties from somewhere on the wifi cards ROM rather than 
the computer's firmware / ACPI Tabes / whatever. If you can tell me where I 
should look I can see if I find out more.

If you think it is helpful or might point towards deeper issues I can try do a 
bisect for whatever patch broke this. I vaguely suspect though that it was 
always broken but by random luck a NULL pointer happened to be on the stack in 
the right place.

> No need to use 'err'. You can directly do
> of_property_read_string_index() in the if statement below.

Check, I'll resend. I found both styles in use (though admittedly reusing 
'err' to print it to dmesg).

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