On 16/07/2020 23:05, Andres Freund wrote: > Hi, > > While testing the error handling of my uring using postgres branch I > just encountered the situation that io_uring_setup() always fails with > ENOMEN. > > It only does so for the user I did the testing on and not for other > users. During the testing a few io_uring using processes were kill -9'd > and a few core-dumped after abort(). No io_uring using processes are > still alive. > > As the issue only happens to the one uid I suspect that > current_user()->locked_mem got corrupted, perhaps after hitting the > limit for real. Any chance it's using SQPOLL mode? > > Unfortunately I do not see any way to debug this without restarting. It > seems the user wide limit isn't exported anywhere? I found > uids_sysfs_init() while grepping around, but it seems that's just a > leftover. > > This happened on 07a56bb875afbe39dabbf6ba7b83783d166863db / 5.8rc5 + > 16. I left the machine running for now, in case there's something that > can be debugged while running. But I've to restart it in a bit. It took > a while to hit this issue, unfortunately. > -- Pavel Begunkov
