On Wed, Jun 12, 2024 at 01:25:07PM +0200, Christian Brauner wrote: > I've been trying to reproduce this with pmem yesterday and wasn't able to. > > What's the kernel config and test config that's used? > The kernel config can be found here: https://github.com/tytso/xfstests-bld/blob/master/kernel-build/kernel-configs/config-6.1 Drop it into .config in the build directory of any kernel sources newer than 6.1, and then run "make olddefconfig". This is all automated in the install-kconfig script which I use: https://github.com/tytso/xfstests-bld/blob/master/kernel-build/install-kconfig The VM has 4 CPU's, and 26GiB of memory, and kernel is booted with the boot command line options "memmap=4G!9G memmap=9G!14G", which sets up fake /dev/pmem0 and /dev/pmem1 devices backed by RAM. This is my poor engineer's way of testing DAX without needing to get access to expensive VM's with pmem. :-) I'm assuming this is a timing-dependant bug which is easiest to trigger on fast devices, so a ramdisk might also work. FWIW, I also can see failures relatively frequently using the ext4/nojournal configuration on a SSD-backed cloud block device (GCE's Persistent Disk SSD product). As a result, if you grab my xfstests-bld repo from github, and then run "qemu-xfstests -c ext4/nojournal C 20 generic/085" it should also reproduce. See the Documentation/kvm-quickstart.md for more details. - Ted
