This commit fixes partly the kernel warning listed below. It can easily
be triggered by sending messages with "cangen -g1 can0" and then
stopping the interface with "ifconfig can0 down". The warning comes from
skb_release_all() and it occurs, because the "ifconfig down" command
clears the running state before calling the device specific stop/close
routine. In the meantime, TX done events may still occur, calling
can_get_echo_skb(), which calls netif_rx() then netif_rx_internal()
and enqueue_to_backlog(). Because the interface is not running any
longer, the skb is finally dropped, causing the warning below. We now
check the running state in gs_usb_receive_bulk_callback() before
processing the data making the occurrence of that warning much much less
probable. BTW, the warning can cause rather high latencies of 500 ms...
that's likely the reason why it's there. The problem should show up on
other (USB) CAN drivers as well.
[ 1694.131475] ------------[ cut here ]------------
[ 1694.139911] WARNING: CPU: 0 PID: 0 at skb_release_head_state+0x9e/0xb0
[ 1694.147206] Modules linked in: intel_telemetry_pltdrv intel_pmc_ipc intel_punit_ipc intel_telemetry_core x86_pkg_temp_thermal igb tpm_tis tpm_tis_core btusb btrtl dca tpm lpc_ich btbcm spi_pxa2xx_platform mei_me btintel mei thermal rfcomm bluetooth ecdh_generic ntngdm_i2c ntngdm_core ntngdm_bl ntngdm_tsi ntngdm_irq ntngdm_hwmon i915 video
[ 1694.180782] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G U W 4.14.51apollolake #1
[ 1694.189828] Hardware name: Default string Default string/AGCO_NT-NG, BIOS X3.00c#AGCO BETA 09/19/2019
[ 1694.200136] task: ffffffff840104c0 task.stack: ffffffff84000000
[ 1694.206753] RIP: 0010:skb_release_head_state+0x9e/0xb0
[ 1694.212494] RSP: 0018:ffff8b2b3fc03cb0 EFLAGS: 00010006
[ 1694.218333] RAX: ffffffff835a4fb0 RBX: ffff8b2b3a20b100 RCX: 0000000000000018
[ 1694.226310] RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
[ 1694.234284] RBP: 0000000000020ac0 R08: 0000000000000014 R09: 0000000000000014
[ 1694.242259] R10: 0000000000000000 R11: ffff8b2b3a7a2180 R12: ffff8b2b3fc03d40
[ 1694.250235] R13: ffff8b2b3a20b100 R14: ffff8b2b3fc20bcc R15: 0000000000000086
[ 1694.258211] FS: 0000000000000000(0000) GS:ffff8b2b3fc00000(0000) knlGS:0000000000000000
[ 1694.267256] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1694.273678] CR2: 00007f83a2db5130 CR3: 0000000179c6a000 CR4: 00000000003406f0
[ 1694.281653] Call Trace:
[ 1694.284383] <IRQ>
[ 1694.286629] skb_release_all+0x9/0x20
[ 1694.290720] kfree_skb+0x19/0x40
[ 1694.294327] enqueue_to_backlog+0x7e/0x230
[ 1694.298906] ? recalibrate_cpu_khz+0x10/0x10
[ 1694.303677] ? ktime_get_with_offset+0x4f/0xb0
[ 1694.308644] netif_rx_internal+0x56/0x150
[ 1694.313126] can_get_echo_skb+0x37/0x60
[ 1694.317415] gs_usb_receive_bulk_callback+0x111/0x320
[ 1694.323063] __usb_hcd_giveback_urb+0x7b/0xf0
[ 1694.327924] xhci_giveback_urb_in_irq.isra.55+0x6d/0x90
[ 1694.333765] xhci_td_cleanup+0xcb/0x150
[ 1694.338051] xhci_irq+0x66a/0x20b0
[ 1694.341854] ? rcu_accelerate_cbs+0x3a/0x190
[ 1694.346628] __handle_irq_event_percpu+0x32/0xd0
[ 1694.351791] handle_irq_event_percpu+0x2b/0x70
[ 1694.356757] handle_irq_event+0x2f/0x50
[ 1694.361044] handle_edge_irq+0x72/0x190
[ 1694.365331] handle_irq+0x17/0x20
[ 1694.369038] do_IRQ+0x3c/0xc0
[ 1694.372355] common_interrupt+0x7a/0x7a
[ 1694.376639] </IRQ>
[ 1694.378981] RIP: 0010:cpuidle_enter_state+0x122/0x200
[ 1694.384622] RSP: 0018:ffffffff84003ea8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffbd
[ 1694.393087] RAX: ffff8b2b3fc1fa00 RBX: 0000000000000002 RCX: 0000018a721a5ae8
[ 1694.401063] RDX: 0000018a721a5ae8 RSI: 0000000050523fbe RDI: 0000000000000000
[ 1694.409040] RBP: ffff8b2b3aa13600 R08: 0000000000000193 R09: 000000000000012a
[ 1694.417015] R10: ffffffff84003e90 R11: 00000000000000ef R12: 0000018a721a5ae8
[ 1694.424990] R13: 0000018a72199308 R14: 0000000000000002 R15: 0000000072efca78
[ 1694.432970] ? cpuidle_enter_state+0x11e/0x200
[ 1694.437937] do_idle+0x161/0x1a0
[ 1694.441544] cpu_startup_entry+0x6a/0x70
[ 1694.445927] start_kernel+0x414/0x434
[ 1694.450023] secondary_startup_64+0xa5/0xb0
[ 1694.454697] Code: 88 96 4f 17 00 74 02 5b c3 5b e9 4e 15 bc ff e8 d9 33 04 00 eb dd e8 c2 5a 0d 00 eb 9f 48 83 e7 fe e8 07 d7 01 00 e9 75 ff ff ff <0f> 0b eb ad 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 53 48 89
[ 1694.475869] ---[ end trace 063196a1141471b3 ]---
Signed-of-by: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
---
drivers/net/can/usb/gs_usb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index a4b4b74..1893267 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -321,7 +321,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
netdev = dev->netdev;
stats = &netdev->stats;
- if (!netif_device_present(netdev))
+ if (!netif_device_present(netdev) || !netif_running(netdev))
return;
if (hf->echo_id == -1) { /* normal rx */
--
1.9.1
