[Intel-wired-lan] [PATCH] ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero.
Ken Cox
jkc at redhat.com
Mon Aug 9 12:50:03 UTC 2021
It is possible to disable VFs while the PF driver is processing requests
from the VF driver. This can result in a panic.
BUG: unable to handle kernel paging request at 000000000000106c
PGD 0 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 8 PID: 0 Comm: swapper/8 Kdump: loaded Tainted: G I --------- - -
Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020
RIP: 0010:ixgbe_msg_task+0x4c8/0x1690 [ixgbe]
Code: 00 00 48 8d 04 40 48 c1 e0 05 89 7c 24 24 89 fd 48 89 44 24 10 83 ff 01 0f 84 b8 04 00 00 4c 8b 64 24 10 4d 03 a5 48 22 00 00 <41> 80 7c 24 4c 00 0f 84 8a 03 00 00 0f b7 c7 83 f8 08 0f 84 8f 0a
RSP: 0018:ffffb337869f8df8 EFLAGS: 00010002
RAX: 0000000000001020 RBX: 0000000000000000 RCX: 000000000000002b
RDX: 0000000000000002 RSI: 0000000000000008 RDI: 0000000000000006
RBP: 0000000000000006 R08: 0000000000000002 R09: 0000000000029780
R10: 00006957d8f42832 R11: 0000000000000000 R12: 0000000000001020
R13: ffff8a00e8978ac0 R14: 000000000000002b R15: ffff8a00e8979c80
FS: 0000000000000000(0000) GS:ffff8a07dfd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000106c CR3: 0000000063e10004 CR4: 00000000007726e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
? ttwu_do_wakeup+0x19/0x140
? try_to_wake_up+0x1cd/0x550
? ixgbevf_update_xcast_mode+0x71/0xc0 [ixgbevf]
ixgbe_msix_other+0x17e/0x310 [ixgbe]
__handle_irq_event_percpu+0x40/0x180
handle_irq_event_percpu+0x30/0x80
handle_irq_event+0x36/0x53
handle_edge_irq+0x82/0x190
handle_irq+0x1c/0x30
do_IRQ+0x49/0xd0
common_interrupt+0xf/0xf
This can be eventually be reproduced with the following script:
while :
do
echo 63 > /sys/class/net/ens3f0/device/sriov_numvfs
sleep 1
echo 0 > /sys/class/net/ens3f0/device/sriov_numvfs
sleep 1
done
Signed-off-by: Ken Cox <jkc at redhat.com>
---
drivers/net/ethernet/intel/ixgbe/ixgbe.h | 1 +
drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 9 +++++++++
2 files changed, 10 insertions(+)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index a604552fa634..696bb2a61ea7 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -807,6 +807,7 @@ enum ixgbe_state_t {
__IXGBE_PTP_RUNNING,
__IXGBE_PTP_TX_IN_PROGRESS,
__IXGBE_RESET_REQUESTED,
+ __IXGBE_DISABLING_VFS,
};
struct ixgbe_cb {
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index 214a38de3f41..e2df7729876d 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -206,8 +206,12 @@ int ixgbe_disable_sriov(struct ixgbe_adapter *adapter)
unsigned int num_vfs = adapter->num_vfs, vf;
int rss;
+ while (test_and_set_bit(__IXGBE_DISABLING_VFS, &adapter->state))
+ usleep_range(1000, 2000);
+
/* set num VFs to 0 to prevent access to vfinfo */
adapter->num_vfs = 0;
+ clear_bit(__IXGBE_DISABLING_VFS, &adapter->state);
/* put the reference to all of the vf devices */
for (vf = 0; vf < num_vfs; ++vf) {
@@ -1292,6 +1296,7 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
return retval;
}
+
static void ixgbe_rcv_ack_from_vf(struct ixgbe_adapter *adapter, u32 vf)
{
struct ixgbe_hw *hw = &adapter->hw;
@@ -1307,6 +1312,9 @@ void ixgbe_msg_task(struct ixgbe_adapter *adapter)
struct ixgbe_hw *hw = &adapter->hw;
u32 vf;
+ if (test_and_set_bit(__IXGBE_DISABLING_VFS, &adapter->state))
+ return;
+
for (vf = 0; vf < adapter->num_vfs; vf++) {
/* process any reset requests */
if (!ixgbe_check_for_rst(hw, vf))
@@ -1320,6 +1328,7 @@ void ixgbe_msg_task(struct ixgbe_adapter *adapter)
if (!ixgbe_check_for_ack(hw, vf))
ixgbe_rcv_ack_from_vf(adapter, vf);
}
+ clear_bit(__IXGBE_DISABLING_VFS, &adapter->state);
}
void ixgbe_disable_tx_rx(struct ixgbe_adapter *adapter)
--
2.26.3
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