Messages in this thread | | | From | Andy Shevchenko <> | Date | Mon, 20 Jun 2022 13:01:28 +0200 | Subject | Re: Boot stall regression from "printk for 5.19" merge |
| |
+Cc: Ilpo, a new maintainer for the driver
On Mon, Jun 20, 2022 at 12:46 PM Marek Behún <kabel@kernel.org> wrote: > > On Mon, 20 Jun 2022 19:13:37 +0900 > Sergey Senozhatsky <senozhatsky@chromium.org> wrote: > > > On (22/06/20 12:02), Marek Behún wrote: > > > > On (22/06/19 20:49), Marek Behún wrote: > > > > [..] > > > > > causes a regression on arm64 (Marvell CN9130-CRB board) where the > > > > > system boot freezes in most cases (and is unusable until restarted by > > > > > watchdog), or, in some cases boots, but the console output gets mangled > > > > > for a while (the serial console spits garbage characters). > > > > > > > > Can you please try disabling console kthreads and see how the boot > > > > process goes? Just `return 0` from printk_activate_kthreads() (I think > > > > this should do the trick). > > > > > > This indeed makes the problem go away... > > > > Oh... OK. Didn't expect that :) > > > > > > > The garbage example: > > > > > > > > > > ... > > > > > [ 0.920951] raid6: using neon recovery algorithm > > > > > [ 0.921228] iommu: Default domain type: Translated > > > > > % > > > > > > > > > > gb@k+cFL/[ 4.954974] DSA: tree 0 setup > > > > > [ 4.955286] cfg80211: Loading compiled-in X.509 certificates for regulatory database > > > > > > > > This is pretty suspicious. I don't see how console kthreads would > > > > corrupt the output. I suspect that something else is going on, some > > > > memory corruption, etc. > > > > > > Maybe multiple threads are writing to serial registers, or something... > > > > That's possible. Console drivers usually should grab port->lock for > > write(), but maybe something is missing in the driver you use. What > > console driver are you using? > > compatible = "snps,dw-apb-uart", so drivers/tty/serial/8250/8250_dw.c > > seems that the function dw8250_serial_out() does not use the spinlock... > > Marek
-- With Best Regards, Andy Shevchenko
| |