Re: [PATCH ath-next] Revert "wifi: ath12k: add panic handler"

[Joonhoe Kim <26rote@gmail.com>]

On Thu, Jun 11, 2026 at 08:23:32PM -0700, Yingying Tang wrote:
> ath12k_core_panic_handler() is invoked via atomic_notifier_call_chain(),
> which runs inside an RCU read-side critical section.

I hit this on a WCN7860 (hw2.0, PCI) in a Lenovo Legion Tab Y700 Gen 5
(Kaanapali), v7.3-rc4 plus board patches. Here the panic never got past
the notifier:

  SMP: stopping secondary CPUs
  Voluntary context switch within RCU read-side critical section!
   schedule_timeout
   __mhi_device_get_sync
   ath12k_wifi7_pci_bus_wake_up
   ath12k_pci_read32
   ath12k_pci_sw_reset
   ath12k_pci_panic_handler
   atomic_notifier_call_chain
   vpanic

A hung_task panic stayed hung until a forced restart, and a sysrq crash
only ended in a reset after about 50 s.

With the handler removed, a sysrq crash reboots normally, and after the
reboot WCN7860 is enumerated again (PCIe Gen3 x2 link up) and Wi-Fi
works.

Tested-by: Joonhoe Kim <26rote@gmail.com>

On Baochen's question, the handler came in with 809055628bce, so:
Fixes: 809055628bce ("wifi: ath12k: add panic handler")