https://bugzilla.kernel.org/show_bug.cgi?id=201685 --- Comment #69 from Theodore Tso (tytso@xxxxxxx) --- Hi Jimmy, how certain are you that e1333462e3 is stable for you? i.e., how long have you been running with that kernel and how quickly do your other git bisect bad build fail for you? And I assume you have run a forced fsck (ideally while 4.18 is booted) on the file system before installing each kernel that you were bisect testing, right? Otherwise it's possible that a previous bad kernel had left the file system corrupted, and so a particular kernel stumbled on a corruption, but it wasn't actually *caused* by that kernel. The reason why I'm asking these question is that based on your bisect, it would *appear* that the problem was introduced by an RCU change. If you look at the output of "git log --oneline e1333462e3..cd23ac8ddb7" all of the changes are RCU related. That's a bit surprising, since given that only some users are seeing this problem. If there was a regression was introduced in the RCU subsystem, I would have expected a large number of people would have been complaining, with many more bugs than just in ext4. And there is some evidence that your file system has gotten corrupted. The warnings you report here: [12421.017028] EXT4-fs warning (device dm-4): kmmpd:191: kmmpd being stopped since filesystem has been remounted as readonly. [12434.457445] EXT4-fs warning (device dm-4): ext4_multi_mount_protect:325: MMP interval 42 higher than expected, please wait. Are caused by the MMP feature being enabled on your kernel. It's not enabled by default, and unless you have relatively exotic hardware (e.g., dual-attached SCSI disks that can be reached by two servers for failover) there is no reason to turn on the MMP feature. You can disable it via: "tune2fs -O ^mmp /dev/dm-4". (And you can enable it via "tune2fs -O mmp /dev/dm-4".) So apparently while you were running your tests, the superblock had at least one bit (the MMP feature bit) flipped by a rogue kernel. -- You are receiving this mail because: You are watching the assignee of the bug.
