Re: [PATCH v3 0/2] PCI/IOV: Fix deadlock when removing PF with enabled SR-IOV

[Dragos Tatulea <dtatulea@nvidia.com>]

On 23.02.26 19:34, Dragos Tatulea wrote:
> 
> 
> On 23.02.26 18:33, Benjamin Block wrote:
>> On Mon, Feb 23, 2026 at 03:10:35PM +0100, Dragos Tatulea wrote:
>>> After pulling in these commits in our internal tree we can see the
>>> lockdep splat from below in many internal tests. We are still trying to
>>> find an easy repro for this. We had to internally revert both of them.
>>>
>>> I noticed some similar discussion in another thread [1] but there it
>>> seems that these changes are actually fixing the issue which is not
>>> the case for us.
>>>
>>> ------------[ cut here ]------------
>>> WARNING: drivers/pci/remove.c:130 at pci_stop_and_remove_bus_device+0x39/0x40, CPU#2: modprobe/12956
>>> Modules linked in: mlx5_core(-) act_tunnel_key vxlan dummy act_mirred act_gact cls_flower act_police act_ct nf_flow_table [...]
>>> CPU: 2 UID: 0 PID: 12956 Comm: modprobe Not tainted 6.19.0net_next_e834b5e #1 PREEMPT 
>>> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
>>> RIP: 0010:pci_stop_and_remove_bus_device+0x39/0x40
>>> Code: [...]
>>> RSP: 0018:ffff888164c9fd10 EFLAGS: 00010246
>>> RAX: 0000000000000000 RBX: ffff888188ff2000 RCX: 0000000000000001
>>> RDX: 0000000000000046 RSI: ffffffff8307e068 RDI: ffff88816bf4c9c0
>>> RBP: ffff888188ff2000 R08: 00000000000000f4 R09: ffff88816bf4c080
>>> R10: 0000000000000001 R11: 0000000000000003 R12: 0000000000000000
>>> R13: ffff888164c9fd27 R14: 0000000000000002 R15: 0000000000000000
>>> FS:  00007f52364bd740(0000) GS:ffff8885a9019000(0000) knlGS:0000000000000000
>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> CR2: 00005622dbf749d8 CR3: 0000000169132004 CR4: 0000000000372eb0
>>> Call Trace:
>>>  <TASK>
>>>  pci_iov_remove_virtfn+0xbd/0x120
>>>  sriov_disable+0x30/0xe0
>>>  mlx5_sriov_disable+0x50/0xa0 [mlx5_core]
>>>  remove_one+0x68/0xe0 [mlx5_core]
>>>  pci_device_remove+0x39/0xa0
>>>  device_release_driver_internal+0x1e4/0x240
>>>  driver_detach+0x47/0x90
>>>  bus_remove_driver+0x84/0x110
>>>  pci_unregister_driver+0x3b/0x90
>>
>> This looks pretty much like what Ionut is trying to fix in
>> v1: https://lore.kernel.org/linux-pci/20260214193235.262219-3-ionut.nechita@windriver.com/T/
>> v2: https://lore.kernel.org/linux-pci/20260219212648.82606-1-ionut.nechita@windriver.com/T/
>>
>> Maybe try giving those patches a spin. I think one easy way to hit this sort
>> of thing is to try unbinding a PF that has 1 or more VFs attached to it from
>> some device driver. The "trick" is that SR-IOV has to be active.
> Thanks or the pointer. Will try it.
> 
Took the v2 and it did the trick. Thanks!
Is it worth a Tested-by tag from me?

Thanks,
Dragos