Hello! Massimo B. wrote: > have you been able to modprobe bcache on 4.16.x? > I have asked on IRC and it seemed nobody tried before, just me. > So nobody was able to confirm or confirm against... > > https://github.com/dracutdevs/dracut/issues/393 > At least here I'm not able to modprobe the bcache module from an initramfs. > So I can't boot with that 4.16.x kernel as my root fs is on bcache. Here's another user of bcache on rootfs with kernel 4.16. Upgrading to kernel 4.16 leaves my system unbootable because systemd waits forever for the rootfs device to appear. I already posted to the github issue tho it not seems dracut related. Here's the gist of what I wrote: Inspecting the situation by setting a breakpoint in dracut, I was able to confirm that the bcache module does not initialize in 4.16. It is built right into my kernel, so there's nothing to load as a module. I expect bcache to be visible in /sys/fs/bcache but there's nothing there. The sysfs structure of bcache is completely missing as if I didn't compile my kernel with bcache support at all. It looks similar to Massimos observation having an error message in dmesg about "could not allocate memory", just that - probably due to having bcache built into the kernel instead of loadable module - I don't see any clue of bcache at all in dmesg. Reverting to kernel 4.15 makes my system bootable again. I think there's something very broken with memory allocations in 4.16. I've looked at the kernel changes between 4.15 to 4.16 but due to lack of in-depth knowledge and the vast amount of changes, I found no obvious git log messages concerning memory management. And I don't have a setup to do a proper bisect for this. Looking at the bcache changes from 4.15 to 4.16, I don't see anything suspicious. How could we help investigating this further? I'd really want to jump to 4.16 due to the inode/iversion related changes. I'd be willing to try patches that could solve this. -- Regards, Kai Replies to list-only preferred. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
