[0/2] arm64/kdump: Fix OOPS and OOM issues in kdump kernel

Message

Bhupesh Sharma July 1, 2020, 10:14 p.m. UTC

Prabhakar recently reported a kdump kernel boot failure on ThunderX2
arm64 plaforms (which I was able to reproduce on ampere arm64 machines
as well), (see [1]), which is seen when a corner case is hit on some
arm64 boards when kdump kernel runs with "cgroup_disable=memory" passed
to the kdump kernel (via bootargs) and the crashkernel was originally
allocated from either a ZONE_DMA32 memory or mixture of memory chunks
belonging to both ZONE_DMA and ZONE_DMA32 regions.

While [PATCH 1/2] fixes the OOPS inside mem_cgroup_get_nr_swap_pages()
function, [PATCH 2/2] fixes the OOM seen inside the kdump kernel by
allocating the crashkernel inside ZONE_DMA region only.

[1]. https://marc.info/?l=kexec&m=158954035710703&w=4

Cc: Johannes Weiner <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Vladimir Davydov <[e-mail]>
Cc: James Morse <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Reported-by: Prabhakar Kushwaha <[e-mail]>
Signed-off-by: Bhupesh Sharma <[e-mail]>

Bhupesh Sharma (2):
  mm/memcontrol: Fix OOPS inside mem_cgroup_get_nr_swap_pages()
  arm64: Allocate crashkernel always in ZONE_DMA

 arch/arm64/mm/init.c | 16 ++++++++++++++--
 mm/memcontrol.c      |  9 ++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)