Kworker hangs. One CPU fully used forever

Software SW bugs discussion
1

Hello,
Sometimes after reboot my router works very slowly. I started to dig into this problem and I found that one process hanged (kworker).

cpu
cpu1076×487 16.9 KB

One core is fully used and that remains forever.

Have you got any idea how to find a cause and how to fix it?

Turris OS version 3.9.5
Kernel version 4.4.113-1e4a549d177ab3da12b2052fba6a4dd5-1

Some kernel logs:

    [ 2336.786760] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2337.234213] ath: phy1: Chip reset failed
    [ 2337.238146] ath: phy1: Unable to reset channel, reset status -22
    [ 2337.710763] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2338.158200] ath: phy1: Chip reset failed
    [ 2338.162137] ath: phy1: Unable to reset channel, reset status -22
    [ 2338.635093] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2339.082533] ath: phy1: Chip reset failed
    [ 2339.086465] ath: phy1: Unable to reset channel, reset status -22
    [ 2339.559069] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2340.006520] ath: phy1: Chip reset failed
    [ 2340.010458] ath: phy1: Unable to reset channel, reset status -22
    [ 2340.483401] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2340.930846] ath: phy1: Chip reset failed
    [ 2340.934779] ath: phy1: Unable to reset channel, reset status -22
    [ 2340.941207] ath10k_warn: 26 callbacks suppressed
    [ 2340.941217] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2340.941226] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2340.941240] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2340.941249] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2340.941258] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2340.941265] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
    [ 2341.409107] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2341.856972] ath: phy1: Chip reset failed
    [ 2341.860914] ath: phy1: Unable to reset channel, reset status -22
    [ 2342.333507] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2342.780926] ath: phy1: Chip reset failed
    [ 2342.784861] ath: phy1: Unable to reset channel, reset status -22
    [ 2343.257319] ath: phy1: DMA failed to stop in 10 ms AR_CR=0xdeadbeef AR_DIAG_SW=0xdeadbeef DMADBG_7=0xdeadbeef
    [ 2343.704989] ath: phy1: Chip reset failed
    [ 2343.708930] ath: phy1: Unable to reset channel, reset status -22
2

Hi,
thank you for attaching kernel log, but would you be so kind and contact us on this matter at our email address, which is tech.support(at)turris.cz and please send us diagnostics, which you can generate in Foris.

3

Hello,
I will even send you the whole router, because I made a warranty claim because of disappearing 2.4ghz wifi card.

Cheers

4

Hello,
thanks for letting me know.

We received your router a few days ago.

It’s repaired and we’re sending it back! :slight_smile:

1 Like
5

Just curious. Did you identify the kernel hang problem in my router? Now it seems to be better than before (working for 12 hours, but still).

6

If I remember correctly it was caused by faulty WiFi card, which was replaced and now it should work w/o any issues.

7

ok. Thanks for clarification :slight_smile: