Re: [patch V3 00/35] genirq/msi, PCI/MSI: Spring cleaning - Part 2

From: Thomas Gleixner
Date: Tue Dec 14 2021 - 11:36:07 EST


On Tue, Dec 14 2021 at 10:22, Nishanth Menon wrote:
> On 10:41-20211214, Thomas Gleixner wrote:
> Agreed that the warning is fine, the null pointer exception that follows
> [1] [2] it however does'nt look right and it can be trivially fixed with the
> following fixup for ee90787487bc ("genirq/msi: Provide
> msi_device_populate/destroy_sysfs()") below, with that the log looks
> like [3] - the warn is good, the null pointer exception and resultant
> crash could be avoided (not saying this is the best solution):

Aaargh.

[ 13.478122] Call trace:
[ 13.509042] msi_device_destroy_sysfs+0x18/0x88
[ 13.509058] msi_domain_free_irqs+0x34/0x58
[ 13.509064] pci_msi_teardown_msi_irqs+0x30/0x3c
[ 13.509072] free_msi_irqs+0x78/0xd4
[ 13.509077] pci_disable_msix+0x138/0x164
[ 13.529930] pcim_release+0x70/0x238
[ 13.529942] devres_release_all+0x9c/0xfc
[ 13.529951] device_release_driver_internal+0x1a0/0x244
[ 13.542725] device_release_driver+0x18/0x24
[ 13.542741] iwl_req_fw_callback+0x1a28/0x1ddc [iwlwifi]
[ 13.552308] request_firmware_work_func+0x50/0x9c
[ 13.552320] process_one_work+0x194/0x25c

That's not a driver problem, that's an ordering issue vs. the devres
muck. Let me go back to the drawing board. Sigh...

Thanks,

tglx