On Thu, 15 Dec 2022 16:12:50 +0200, Vladimir Oltean wrote:

Michael Walle says he noticed the following stack trace while performing
a shutdown with "reboot -f". He suggests he got "lucky" and just hit the
correct spot for the reboot while there was a packet transmission in
flight.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 6.1.0-rc5-00088-gf3600ff8e322 #1930
Hardware name: Kontron KBox A-230-LS (DT)
pc : iommu_get_dma_domain+0x14/0x20
lr : iommu_dma_map_page+0x9c/0x254
Call trace:
 iommu_get_dma_domain+0x14/0x20
 dma_map_page_attrs+0x1ec/0x250
 enetc_start_xmit+0x14c/0x10b0
 enetc_xmit+0x60/0xdc
 dev_hard_start_xmit+0xb8/0x210
 sch_direct_xmit+0x11c/0x420
 __dev_queue_xmit+0x354/0xb20
 ip6_finish_output2+0x280/0x5b0
 __ip6_finish_output+0x15c/0x270
 ip6_output+0x78/0x15c
 NF_HOOK.constprop.0+0x50/0xd0
 mld_sendpack+0x1bc/0x320
 mld_ifc_work+0x1d8/0x4dc
 process_one_work+0x1e8/0x460
 worker_thread+0x178/0x534
 kthread+0xe0/0xe4
 ret_from_fork+0x10/0x20
Code: d503201f f9416800 d503233f d50323bf (f9404c00)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt

[...]

Applied to will (for-joerg/arm-smmu/fixes), thanks!

[1/2] iommu/arm-smmu: don't unregister on shutdown
      https://git.kernel.org/will/c/42afa58a2431
[2/2] iommu/arm-smmu-v3: don't unregister on shutdown
      https://git.kernel.org/will/c/1dc4b4b5c5e7

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev