Op 21-10-2020 om 00:58 schreef Thinh Nguyen:
Thinh Nguyen wrote:
Hi,
Ferry Toth wrote:
Op 20-10-2020 om 14:32 schreef Felipe Balbi:
Hi,
Ferry Toth <fntoth@xxxxxxxxx> writes:
8< snip
[ 12.657416] CR2: 0000000100000000
[ 12.660729] ---[ end trace 9b92dea6da33c71e ]---
It this something you can reproduce on your end? Ferry, can you get
dwc3
trace logs when this happens? ftrace_dump_on_oops may help here.
I will do that tonight. Is flipping on ftrace_dump_on_oops
sufficient or
do I need to do more?
you'd have to enable dwc3 trace events first ;-)
BTW after posting this I found in host mode dwc3 is not working
properly
either. No oops, but no driver get loaded on device plug in.
okay
Ehem, you maybe only me to enable /dwc3/dwc3_ep_dequeue/enable:
root@edison:/boot# uname -a
Linux edison 5.9.0-edison-acpi-standard #1 SMP Mon Oct 19 20:17:04 UTC
2020 x86_64 x86_64 x86_64 GNU/Linux
root@edison:/boot# echo 1 >
/sys/kernel/debug/tracing/events/dwc3/dwc3_ep_dequeue/enable
root@edison:/boot# echo 1 > /proc/sys/kernel/ftrace_dump_on_oops
root@edison:/boot#
root@edison:/boot# [ 2608.585323] BUG: kernel NULL pointer
dereference, address: 0000000000000000
[ 2608.592288] #PF: supervisor read access in kernel mode
[ 2608.597419] #PF: error_code(0x0000) - not-present page
[ 2608.602549] PGD 0 P4D 0
[ 2608.605090] Oops: 0000 [#1] SMP PTI
[ 2608.608580] CPU: 1 PID: 733 Comm: irq/15-dwc3 Not tainted
5.9.0-edison-acpi-standard #1
[ 2608.616571] Hardware name: Intel Corporation Merrifield/BODEGA BAY,
BIOS 542 2015.01.21:18.19.48
[ 2608.625356] RIP: 0010:dwc3_gadget_ep_dequeue+0x41/0x1c0
[ 2608.630580] Code: e9 51 01 00 00 4c 8d a3 30 01 00 00 4c 89 e7 e8
15 e6 42 00 49 8b 4e 48 49 89 c5 49 8d 46 48 48 8d 51 a0 48 39 c8 75
0f eb 2e <48> 8b 4a 60 48 8d 51 a0 48 39 c8 74 21 48 39 d5 75 ee 45 31
f6 4c
[ 2608.649320] RSP: 0018:ffffa838002a7c40 EFLAGS: 00010087
[ 2608.654543] RAX: ffff9a5f4609c048 RBX: ffff9a5f46f48028 RCX:
0000000000000000
[ 2608.661666] RDX: ffffffffffffffa0 RSI: 0000000000000008 RDI:
ffff9a5f46f48158
[ 2608.668790] RBP: ffff9a5f7bd09b40 R08: 00000000000002d8 R09:
ffff9a5f7dd6a000
[ 2608.675913] R10: ffffa838002a7d90 R11: ffff9a5f46f48300 R12:
ffff9a5f46f48158
[ 2608.683039] R13: 0000000000000046 R14: ffff9a5f4609c000 R15:
ffff9a5f7ad77e00
[ 2608.690165] FS: 0000000000000000(0000) GS:ffff9a5f7e300000(0000)
knlGS:0000000000000000
[ 2608.698244] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2608.703980] CR2: 0000000000000000 CR3: 000000003780a000 CR4:
00000000001006e0
[ 2608.711102] Call Trace:
[ 2608.713561] usb_ep_dequeue+0x19/0x80
[ 2608.717234] u_audio_stop_capture+0x54/0x9a [u_audio]
[ 2608.722289] afunc_set_alt+0x73/0x80 [usb_f_uac2]
I took a look at how the audio function is handling switching alternate
setting and dequeuing endpoints, and I think I found the issue.
Here's a snippet of the free_ep() code in u_audio.c:
static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
{
.....
for (i = 0; i < params->req_number; i++) {
if (prm->ureq[i].req) {
usb_ep_dequeue(ep, prm->ureq[i].req);
usb_ep_free_request(ep, prm->ureq[i].req);
prm->ureq[i].req = NULL;
}
}
....
usb_ep_dequeue() can be asynchronous. The dwc3 still has ownership of
the request until it gives back the request. Freeing the request
immediately here will cause a problem.
To confirm my suspicion, can you try this and see if you still get oops?
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index eec8e9a9e3ed..b66eb24ec070 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2031,6 +2031,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
list_for_each_entry_safe(r, t,
&dep->started_list, list)
dwc3_gadget_move_cancelled_request(r);
+ dwc3_gadget_ep_cleanup_cancelled_requests(dep);
goto out;
}
}
This will make usb_ep_dequeue() synchronous. (Note that this is not tested).
Unfortunately, it doesn't work. The trace changes to:
root@edison:~# [ 104.418264] BUG: kernel NULL pointer dereference,
address: 0000000000000000
[ 104.425227] #PF: supervisor instruction fetch in kernel mode
[ 104.430877] #PF: error_code(0x0010) - not-present page
[ 104.436007] PGD 0 P4D 0
[ 104.438547] Oops: 0010 [#1] SMP PTI
[ 104.442039] CPU: 1 PID: 605 Comm: irq/15-dwc3 Not tainted
5.9.0-edison-acpi-standard #1
[ 104.450027] Hardware name: Intel Corporation Merrifield/BODEGA BAY,
BIOS 542 2015.01.21:18.19.48
[ 104.458802] RIP: 0010:0x0
[ 104.461425] Code: Bad RIP value.
[ 104.464649] RSP: 0018:ffffae584034fbf8 EFLAGS: 00010046
[ 104.469870] RAX: 0000000000000000 RBX: ffff8c198608a028 RCX:
ffff8c19bb87fa00
[ 104.476993] RDX: 00000000ffffff94 RSI: ffff8c19bafa54e0 RDI:
ffff8c198609ee00
[ 104.484118] RBP: ffff8c19bafa54e0 R08: 0000000000000046 R09:
0000000000000238
[ 104.491241] R10: 000000000000002c R11: ffff8c19bcf62490 R12:
ffff8c198609ee00
[ 104.498366] R13: ffff8c198608a028 R14: 0000000000000002 R15:
ffff8c19bb8ff000
[ 104.505493] FS: 0000000000000000(0000) GS:ffff8c19be300000(0000)
knlGS:0000000000000000
[ 104.513572] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 104.519309] CR2: ffffffffffffffd6 CR3: 000000002e80a000 CR4:
00000000001006e0
[ 104.526432] Call Trace:
[ 104.528892] dwc3_gadget_giveback+0xbf/0x120
[ 104.533169] __dwc3_gadget_ep_disable+0xc5/0x250
[ 104.537789] dwc3_gadget_ep_disable+0x3d/0xd0
[ 104.542149] usb_ep_disable+0x1d/0x80
[ 104.545823] u_audio_stop_capture+0x87/0x9a [u_audio]
[ 104.550880] afunc_set_alt+0x73/0x80 [usb_f_uac2]
[ 104.555594] composite_setup+0x20f/0x1b20 [libcomposite]
[ 104.560912] ? configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 104.566921] configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 104.572752] dwc3_ep0_delegate_req+0x24/0x40
[ 104.577022] dwc3_ep0_interrupt+0x40a/0x9d8
[ 104.581205] dwc3_thread_interrupt+0x880/0xf70
BR,
Thinh
