On 07/11/2020 14:09, Josef wrote: >> I haven't got the first email, is it "kernel NULL pointer dereference" >> as in the subject or just freeze? > > that's weird..probably the size of the attached log file is too big... > here dmesg log file > https://gist.github.com/1Jo1/3d0bcefc18f097265f0dc1ef054a87c0 That's much better with the log, thanks! I'll take a look later > >> - did you locate which test hangs it? If so what it uses? e.g. SQPOLL >> sharing, IOPOLL., etc. > > yes, it uses SQPOLL, without sharing, IPOLL is not enabled, and Async > Flag is enabled > >> - is it send/recvmsg, send/recv you use? any other? > > no the tests which occurs the error use these operations: OP_READ, > OP_WRITE, OP_POLL_ADD, OP_POLL_REMOVE, OP_CLOSE, OP_ACCEPT, OP_TIMEOUT > (OP_READ, OP_WRITE and OP_CLOSE async flag is enabled) > >> - does this happen often? > > yeah quite often > >> - you may try `funcgraph __io_sq_thread -H` or even with `io_sq_thread` >> (funcgraph is from bpftools). Or catch that with some other tools. > > I'm not quite familiar with these tools( kernel debugging in general) > I'll take a look tomorrow -- Pavel Begunkov
