ath10k: fix null deref on wmi-tlv when trying spectral scan

[Kalle Valo]

Michal Kazior <michal.kazior at tieto.com> wrote:
> WMI ops wrappers did not properly check for null
> function pointers for spectral scan. This caused
> null dereference crash with WMI-TLV based firmware
> which doesn't implement spectral scan.
> 
> The crash could be triggered with:
> 
>   ip link set dev wlan0 up
>   echo background > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
> 
> The crash looked like this:
> 
>   [  168.031989] BUG: unable to handle kernel NULL pointer dereference at           (null)
>   [  168.037406] IP: [<          (null)>]           (null)
>   [  168.040395] PGD cdd4067 PUD fa0f067 PMD 0
>   [  168.043303] Oops: 0010 [#1] SMP
>   [  168.045377] Modules linked in: ath10k_pci(O) ath10k_core(O) ath mac80211 cfg80211 [last unloaded: cfg80211]
>   [  168.051560] CPU: 1 PID: 1380 Comm: bash Tainted: G        W  O    4.8.0 #78
>   [  168.054336] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
>   [  168.059183] task: ffff88000c460c00 task.stack: ffff88000d4bc000
>   [  168.061736] RIP: 0010:[<0000000000000000>]  [<          (null)>]           (null)
>   ...
>   [  168.100620] Call Trace:
>   [  168.101910]  [<ffffffffa03b9566>] ? ath10k_spectral_scan_config+0x96/0x200 [ath10k_core]
>   [  168.104871]  [<ffffffff811386e2>] ? filemap_fault+0xb2/0x4a0
>   [  168.106696]  [<ffffffffa03b97e6>] write_file_spec_scan_ctl+0x116/0x280 [ath10k_core]
>   [  168.109618]  [<ffffffff812da3a1>] full_proxy_write+0x51/0x80
>   [  168.111443]  [<ffffffff811957b8>] __vfs_write+0x28/0x120
>   [  168.113090]  [<ffffffff812f1a2d>] ? security_file_permission+0x3d/0xc0
>   [  168.114932]  [<ffffffff8109b912>] ? percpu_down_read+0x12/0x60
>   [  168.116680]  [<ffffffff811965f8>] vfs_write+0xb8/0x1a0
>   [  168.118293]  [<ffffffff81197966>] SyS_write+0x46/0xa0
>   [  168.119912]  [<ffffffff818f2972>] entry_SYSCALL_64_fastpath+0x1a/0xa4
>   [  168.121737] Code:  Bad RIP value.
>   [  168.123318] RIP  [<          (null)>]           (null)
> 
> Signed-off-by: Michal Kazior <michal.kazior at tieto.com>

Patch applied to ath-next branch of ath.git, thanks.

18ae68fff392 ath10k: fix null deref on wmi-tlv when trying spectral scan

-- 
https://patchwork.kernel.org/patch/9427495/

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