[PATCH AUTOSEL 5.13 157/189] sfc: avoid double pci_remove of VFs

Sasha Levin
2021-07-06T11:26:01Z

From: Íñigo Huguet <ihuguet@redhat.com>

[ Upstream commit 45423cff1db66cf0993e8a9bd0ac93e740149e49 ]

If pci_remove was called for a PF with VFs, the removal of the VFs was
called twice from efx_ef10_sriov_fini: one directly with pci_driver->remove
and another implicit by calling pci_disable_sriov, which also perform
the VFs remove. This was leading to crashing the kernel on the second
attempt.

Given that pci_disable_sriov already calls to pci remove function, get
rid of the direct call to pci_driver->remove from the driver.

2 different ways to trigger the bug:
- Create one or more VFs, then attach the PF to a virtual machine (at
least with qemu/KVM)
- Create one or more VFs, then remove the PF with:
echo 1 > /sys/bus/pci/devices/PF_PCI_ID/remove

Removing sfc module does not trigger the error, at least for me, because
it removes the VF first, and then the PF.

Example of a log with the error:
list_del corruption, ffff967fd20a8ad0->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:47!
[...trimmed...]
RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x4c
[...trimmed...]
Call Trace:
efx_dissociate+0x1f/0x140 [sfc]
efx_pci_remove+0x27/0x150 [sfc]
pci_device_remove+0x3b/0xc0
device_release_driver_internal+0x103/0x1f0
pci_stop_bus_device+0x69/0x90
pci_stop_and_remove_bus_device+0xe/0x20
pci_iov_remove_virtfn+0xba/0x120
sriov_disable+0x2f/0xe0
efx_ef10_pci_sriov_disable+0x52/0x80 [sfc]
? pcie_aer_is_native+0x12/0x40
efx_ef10_sriov_fini+0x72/0x110 [sfc]
efx_pci_remove+0x62/0x150 [sfc]
pci_device_remove+0x3b/0xc0
device_release_driver_internal+0x103/0x1f0
unbind_store+0xf6/0x130
kernfs_fop_write+0x116/0x190
vfs_write+0xa5/0x1a0
ksys_write+0x4f/0xb0
do_syscall_64+0x5b/0x1a0
entry_SYSCALL_64_after_hwframe+0x65/0xca

Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/sfc/ef10_sriov.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10_sriov.c b/drivers/net/ethernet/sfc/ef10_sriov.c
index 21fa6c0e8873..a5d28b0f75ba 100644
--- a/drivers/net/ethernet/sfc/ef10_sriov.c
+++ b/drivers/net/ethernet/sfc/ef10_sriov.c
@@ -439,7 +439,6 @@ int efx_ef10_sriov_init(struct efx_nic *efx)
void efx_ef10_sriov_fini(struct efx_nic *efx)
{
struct efx_ef10_nic_data *nic_data = efx->nic_data;
- unsigned int i;
int rc;

if (!nic_data->vf) {
@@ -449,14 +448,7 @@ void efx_ef10_sriov_fini(struct efx_nic *efx)
return;
}

- /* Remove any VFs in the host */
- for (i = 0; i < efx->vf_count; ++i) {
- struct efx_nic *vf_efx = nic_data->vf[i].efx;
-
- if (vf_efx)
- vf_efx->pci_dev->driver->remove(vf_efx->pci_dev);
- }
-
+ /* Disable SRIOV and remove any VFs in the host */
rc = efx_ef10_pci_sriov_disable(efx, true);
if (rc)
netif_dbg(efx, drv, efx->net_dev,
--
2.30.2