[PATCH net] iavf: Fix a crash during reset task

From: Ivan Vecera
Date: Tue Nov 08 2022 - 04:37:17 EST


Recent commit aa626da947e9 ("iavf: Detach device during reset task")
removed netif_tx_stop_all_queues() with an assumption that Tx queues
are already stopped by netif_device_detach() in the beginning of
reset task. This assumption is incorrect because during reset
task a potential link event can start Tx queues again.
Revert this change to fix this issue.

Reproducer:
1. Run some Tx traffic (e.g. iperf3) over iavf interface
2. Switch MTU of this interface in a loop

[root@host ~]# cat repro.sh
#!/bin/sh

IF=enp2s0f0v0

iperf3 -c 192.168.0.1 -t 600 --logfile /dev/null &
sleep 2

while :; do
for i in 1280 1500 2000 900 ; do
ip link set $IF mtu $i
sleep 2
done
done
[root@host ~]# ./repro.sh

Result:
[ 306.199917] iavf 0000:02:02.0 enp2s0f0v0: NIC Link is Up Speed is 40 Gbps Full Duplex
[ 308.205944] iavf 0000:02:02.0 enp2s0f0v0: NIC Link is Up Speed is 40 Gbps Full Duplex
[ 310.103223] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 310.110179] #PF: supervisor write access in kernel mode
[ 310.115396] #PF: error_code(0x0002) - not-present page
[ 310.120526] PGD 0 P4D 0
[ 310.123057] Oops: 0002 [#1] PREEMPT SMP NOPTI
[ 310.127408] CPU: 24 PID: 183 Comm: kworker/u64:9 Kdump: loaded Not tainted 6.1.0-rc3+ #2
[ 310.135485] Hardware name: Abacus electric, s.r.o. - servis@xxxxxxxxx Super Server/H12SSW-iN, BIOS 2.4 04/13/2022
[ 310.145728] Workqueue: iavf iavf_reset_task [iavf]
[ 310.150520] RIP: 0010:iavf_xmit_frame_ring+0xd1/0xf70 [iavf]
[ 310.156180] Code: d0 0f 86 da 00 00 00 83 e8 01 0f b7 fa 29 f8 01 c8 39 c6 0f 8f a0 08 00 00 48 8b 45 20 48 8d 14 92 bf 01 00 00 00 4c 8d 3c d0 <49> 89 5f 08 8b 43 70 66 41 89 7f 14 41 89 47 10 f6 83 82 00 00 00
[ 310.174918] RSP: 0018:ffffbb5f0082caa0 EFLAGS: 00010293
[ 310.180137] RAX: 0000000000000000 RBX: ffff92345471a6e8 RCX: 0000000000000200
[ 310.187259] RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000001
[ 310.194385] RBP: ffff92341d249000 R08: ffff92434987fcac R09: 0000000000000001
[ 310.201509] R10: 0000000011f683b9 R11: 0000000011f50641 R12: 0000000000000008
[ 310.208631] R13: ffff923447500000 R14: 0000000000000000 R15: 0000000000000000
[ 310.215756] FS: 0000000000000000(0000) GS:ffff92434ee00000(0000) knlGS:0000000000000000
[ 310.223835] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 310.229572] CR2: 0000000000000008 CR3: 0000000fbc210004 CR4: 0000000000770ee0
[ 310.236696] PKRU: 55555554
[ 310.239399] Call Trace:
[ 310.241844] <IRQ>
[ 310.243855] ? dst_alloc+0x5b/0xb0
[ 310.247260] dev_hard_start_xmit+0x9e/0x1f0
[ 310.251439] sch_direct_xmit+0xa0/0x370
[ 310.255276] __qdisc_run+0x13e/0x580
[ 310.258848] __dev_queue_xmit+0x431/0xd00
[ 310.262851] ? selinux_ip_postroute+0x147/0x3f0
[ 310.267377] ip_finish_output2+0x26c/0x540

Fixes: aa626da947e9 ("iavf: Detach device during reset task")
Cc: Jacob Keller <jacob.e.keller@xxxxxxxxx>
Cc: Patryk Piotrowski <patryk.piotrowski@xxxxxxxxx>
Cc: SlawomirX Laba <slawomirx.laba@xxxxxxxxx>
Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>
---
drivers/net/ethernet/intel/iavf/iavf_main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index 3fc572341781..5abcd66e7c7a 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -3033,6 +3033,7 @@ static void iavf_reset_task(struct work_struct *work)

if (running) {
netif_carrier_off(netdev);
+ netif_tx_stop_all_queues(netdev);
adapter->link_up = false;
iavf_napi_disable_all(adapter);
}
--
2.37.4