Hi Arnd, On Thu, May 12, 2022 at 12:20 PM Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> wrote: > > Hi Arnd, > > On Thu, May 12, 2022 at 10:43 AM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > On Thu, May 12, 2022 at 7:41 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > > * Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> [220511 14:16]: > > > > On Thu, May 5, 2022 at 7:08 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > > > > * Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> [220504 10:35]: > > > > > > Hi Tony, all, > > > > > > > > > > > > since kernel 5.18.x (5.17.x doesn't show this behavior), the system > > > > > > stalls as soon as I invoke the following commands (initializing > > > > > > USB-to-CAN converter): > > > > > > > > > > > > slcand -o -s8 -t hw -S 3000000 /dev/ttyUSB0 > > > > > > ip link set slcan0 up > > > > Oh, I missed this part at first and only looked at the backtrace. > > Which CAN driver > > are you using? It's likely a problem in the kernel driver. > > I am using the slcan driver [1]. > > > CONFIG_DMA_API_DEBUG is still likely to pinpoint the bug, but I might also > > just see it by looking at the right source file. > > I'll try to get more debug info with CONFIG_DMA_API_DEBUG. DMA_API_DEBUG showed nothing new. But disabling the CPUfreq driver "solved" the problem. I have tried different governors and got these two groups: ondemand, schedutil - cause the problem conservative, powersave, performance and userspace - don't cause the problem So far, I have only seen the same debug output that I've initially sent and in most cases, the system stalls without the output. Yegor > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/can/slcan.c?h=v5.18-rc6 > > Yegor > > Arnd
