Re: [v4.12-rc1 regression] mount ext4 fs results in kernel crash on PPC64le host

On Thu, Jun 29, 2017 at 1:41 PM, Eryu Guan [off-list ref] wrote:

On Thu, Jun 29, 2017 at 03:16:10AM +1000, Balbir Singh wrote:

quoted

On Wed, Jun 28, 2017 at 6:32 PM, Eryu Guan [off-list ref] wrote:

<snip>

quoted

Thanks for the excellent bug report, I am a little lost on the stack
trace, it shows a bad page access that we think is triggered by the
mmap changes? The patch changed the return type to integrate the call
into trace-cmd. Could you point me to the tests that can help
reproduce the crash. Could you also suggest how long to try the test
cases for?

Sorry, I should have provided it in the first place. It's as simple as
mounting an ext4 filesystem on my test ppc64le host, i.e.

mkdir -p /mnt/ext4
mkfs -t ext4 -F /dev/sda5
mount /dev/sda5 /mnt/ext4

I tried this test a few times with the kernel and could not reproduce it.
Could you please share the config and compiler details, I'll retry with -rc7.

In the meanwhile, does enabling kmemleak, DEBUG_PAGE_ALLOC,
slub/slab debug, list corruption, etc catch anything at the time of the
corruption?

Thanks,
Balbir Singh.