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

[Dragos Tatulea]

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@xxxxxxxxxxxxx/T/
> v2: https://lore.kernel.org/linux-pci/20260219212648.82606-1-ionut.nechita@xxxxxxxxxxxxx/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.

Thanks,
Dragos