Hi,

On Tue, Aug 28, 2018 at 09:20:34PM +1000, Nicholas Piggin wrote:

Similarly to the previous patch, this tries to optimise dirty/accessed
bits in ptes to avoid access costs of hardware setting them.

This patch results in silent nios2 boot failures, silent meaning that
the boot stalls.

...
Unpacking initramfs...
Freeing initrd memory: 2168K
workingset: timestamp_bits=30 max_order=15 bucket_order=0
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
random: fast init done
random: crng init done

[no further activity until the qemu session is aborted]

Reverting the patch fixes the problem. Bisect log is attached.

Guenter

---
# bad: [387ac6229ecf6e012649d4fc409c5352655a4cf0] Add linux-next specific files for 20180905
# good: [57361846b52bc686112da6ca5368d11210796804] Linux 4.19-rc2
git bisect start 'HEAD' 'v4.19-rc2'
# good: [668570e8389bb076bea9b7531553e1362f5abd11] Merge remote-tracking branch 'net-next/master'
git bisect good 668570e8389bb076bea9b7531553e1362f5abd11
# good: [7f2f69ebf0bcf3e9bcff7d560ba92cee960a66a6] Merge remote-tracking branch 'battery/for-next'
git bisect good 7f2f69ebf0bcf3e9bcff7d560ba92cee960a66a6
# good: [c31458d3e03e3a2edeaab225a22eaf68c07c8290] Merge remote-tracking branch 'rpmsg/for-next'
git bisect good c31458d3e03e3a2edeaab225a22eaf68c07c8290
# good: [e0f43dcbe9af8ac72f39fe92c5d0ee1883546427] Merge remote-tracking branch 'nvdimm/libnvdimm-for-next'
git bisect good e0f43dcbe9af8ac72f39fe92c5d0ee1883546427
# bad: [f509e2c0f3cd11df238f0f1b5ba013fe726decdf] of: ignore sub-page memory regions
git bisect bad f509e2c0f3cd11df238f0f1b5ba013fe726decdf
# good: [2f7eebf30b87534f7e4c3982307579d9adc782a5] ocfs2: fix clusters leak in ocfs2_defrag_extent()
git bisect good 2f7eebf30b87534f7e4c3982307579d9adc782a5
# good: [119eb88c9dd23e305939ad748237100078e304a8] mm/swapfile.c: call free_swap_slot() in __swap_entry_free()
git bisect good 119eb88c9dd23e305939ad748237100078e304a8
# good: [21d64d37adf3ab20b4c3a1951018e84bf815c887] mm: remove vm_insert_pfn()
git bisect good 21d64d37adf3ab20b4c3a1951018e84bf815c887
# good: [90cd1a69010844e9dbfc43279d681d798812b962] cramfs: convert to use vmf_insert_mixed
git bisect good 90cd1a69010844e9dbfc43279d681d798812b962
# good: [c7dd91289b4bb4c400a8a71953511991815f8e6f] mm/cow: optimise pte dirty/accessed bits handling in fork
git bisect good c7dd91289b4bb4c400a8a71953511991815f8e6f
# bad: [87d74ae75700a39effcb8c9ed8a8445e719ac369] hexagon: switch to NO_BOOTMEM
git bisect bad 87d74ae75700a39effcb8c9ed8a8445e719ac369
# bad: [3d1d5b26ac5b4d4193dc618a50cd88de1fb0d360] mm: optimise pte dirty/accessed bit setting by demand based pte insertion
git bisect bad 3d1d5b26ac5b4d4193dc618a50cd88de1fb0d360
# first bad commit: [3d1d5b26ac5b4d4193dc618a50cd88de1fb0d360] mm: optimise pte dirty/accessed bit setting by demand based pte insertion