Re: [4.17 iwlwifi regression] NULL pointer dereference in reg_query_regdb_wmm()

[Eric Biggers <ebiggers3@gmail.com>]

On Mon, May 21, 2018 at 09:47:12PM -0700, Eric Biggers wrote:
> Hi Haim,
> 
> On Mon, May 21, 2018 at 10:10:09AM +0000, Dreyfuss, Haim wrote:
> > Hello,
> > 
> > Can you provide the following information?
> > 1. The *boot* you mentioned is from clean shutdown or from Sx state?
> > 2. Do you know which MCC the driver is trying to update?
> > I will appreciate if you could reproduce it with trace-cmd  (recording at least iwlwifi , iwlwifi_msg -and iwlwifi_ucode)
> > Or if you can't,  just send dmesg  but make sure to set iwlwifi.debug in the kernel parameters to 0x4000
> > 
> 
> It's a clean boot, from powered off.
> 
> I built an v4.17-rc6 kernel with CONFIG_IWLWIFI_DEBUG=y and booted with
> iwlwifi.debug=0x4000.  I've attached the dmesg output and kernel config.
> 
> The crash happens right away, so there's no time to easily run trace-cmd.
> But if the other stuff still isn't enough, I can try booting with the
> NetworkManager service disabled, then enabling it at runtime.
> 
> - Eric

The crash goes away if I replace iwlwifi-7265D-27.ucode in CONFIG_EXTRA_FIRMWARE
with iwlwifi-7265D-29.ucode.  I don't know how well supported using old iwlwifi
firmware versions is supposed to be, but it shouldn't crash the kernel.

- Eric