On 7/2/19 7:10 PM, Jens Axboe wrote: > On 7/2/19 6:00 PM, Christoph Hellwig wrote: >> On Tue, Jul 02, 2019 at 12:37:59PM -0600, Jens Axboe wrote: >>>> I couldn't get that to boot in my test systems even with mainline, >>>> but that seems to be do to systemd waiting for some crap not supported >>>> in the config. >>>> >>>> But with my usual test config I've just completed a test run with >>>> KASAN enabled on a VWC=1 driver with no issues, so this keeps puzzling >>>> me. >>> >>> Let me know what you want me to try. I can't reproduce it in qemu, but >>> it's 100% on my laptop. My qemu drives also have VWC=1, so it's not >>> (just) that. >> >> I seriously have no idea unfortunately. It works fine for me both >> on qemu and on a real WD SN720 drive on my laptop. Just for curiosity >> you could try to pad the bio structure and see if bloating it to the >> old size makes any difference. > > No change with the padding, put it in the same place. Still insta crash > before I get to login prompt, or right after I login and run sync. > >> The other things that comes to mind is that when Johannes removed >> BIO_SEG_VALID there also were some unexplainable side effects, >> I'll look into seeing if there was any similarity. > > Do you have a link? > > I'll try and poke a bit here. The issue is a discard request, 4kb, with a bio but no bi_io_vec. The sync is a red herring, apart from the fact that it triggers the ext4 discards. I'm guessing, when you tried to reproduce, that you didn't have discard enabled? -- Jens Axboe
