Kernel 5.15.1 and bcache

[alexjp]

Hi,

Dunno if the category is right, but just a heads up about kernel 5.15.1 and bcache: LKML: Lin Feng: Re: [PATCH] bcache: fix NULL pointer reference in cached_dev_detach_finish

It has a serious nasty bug. If anyone is affected, there is no data loss ( I talk by experience I was affected ) but there is some command line work to recover the filesystem and cache volume ( I was using btrfs ).

Anyway, just a heads up in case anyone is using bcache !

Cheers!

[SGS]

linux-zen-5.15.2.zen1-1  linux-zen-headers-5.15.2.zen1-1

[anon26187667]

Ah, is this why it took a while for 5.15 to land here? I had been wondering, then spotted it was .2 and wondered even more (but not enough to actually look into it yet).

[alexjp]

I haven't tested 5.12.2 yet .... am a little affraid to test it since the source code for the affected driver is still the same ...

[alexjp]

well, in a clear and successful attempt to show the world that I am a stupid idiot jackass.... after I said I wouldn't do it, I did it!

just one boot and reboot did it, didn't even had to login to the user account. so kernel 5.15.2 is still affected.

and this time I didn't even managed to save the data... had to resort to yesterday's backup.

[alexjp]

gonna try with 5.15.3 :
-> kernel/git/stable/linux.git - Linux kernel stable tree

and
-> kernel/git/stable/linux.git - Linux kernel stable tree

seem patched with the fix to the error on the mailing list!

[alexjp]

only a few hours of uptime, but 5.15.3 seems to be good on bcache.

confirmed with linux-xanmod-tt-5.15.3

also .... bcache users can check the bcache-tools of gentoo's patch: https://gitweb.gentoo.org/repo/gentoo.git/plain/sys-fs/bcache-tools/files/1.1/bcache-tools-add-bcache-status.patch

which adds bcache-status, which is very handy !