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Date:   Thu, 31 Mar 2022 11:55:47 -0400
From:   Qian Cai <quic_qiancai@quicinc.com>
To:     Muchun Song <songmuchun@bytedance.com>
CC:     <dan.j.williams@intel.com>, <willy@infradead.org>, <jack@suse.cz>,
        <viro@zeniv.linux.org.uk>, <akpm@linux-foundation.org>,
        <apopple@nvidia.com>, <shy828301@gmail.com>,
        <rcampbell@nvidia.com>, <hughd@google.com>,
        <xiyuyang19@fudan.edu.cn>, <kirill.shutemov@linux.intel.com>,
        <zwisler@kernel.org>, <hch@infradead.org>,
        <linux-fsdevel@vger.kernel.org>, <nvdimm@lists.linux.dev>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        <duanxiongchun@bytedance.com>, <smuchun@gmail.com>
Subject: Re: [PATCH v5 0/6] Fix some bugs related to ramp and dax
Message-ID: <YkXPA69iLBDHFtjn@qian>
References: <20220318074529.5261-1-songmuchun@bytedance.com>
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On Fri, Mar 18, 2022 at 03:45:23PM +0800, Muchun Song wrote:
> This series is based on next-20220225.
> 
> Patch 1-2 fix a cache flush bug, because subsequent patches depend on
> those on those changes, there are placed in this series.  Patch 3-4
> are preparation for fixing a dax bug in patch 5.  Patch 6 is code cleanup
> since the previous patch remove the usage of follow_invalidate_pte().

Reverting this series fixed boot crashes.

 KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
 Mem abort info:
   ESR = 0x96000004
   EC = 0x25: DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
   FSC = 0x04: level 0 translation fault
 Data abort info:
   ISV = 0, ISS = 0x00000004
   CM = 0, WnR = 0
 [dfff800000000003] address between user and kernel address ranges
 Internal error: Oops: 96000004 [#1] PREEMPT SMP
 Modules linked in: cdc_ether usbnet ipmi_devintf ipmi_msghandler cppc_cpufreq fuse ip_tables x_tables ipv6 btrfs blake2b_generic libcrc32c xor xor_neon raid6_pq zstd_compress dm_mod nouveau crct10dif_ce drm_ttm_helper mlx5_core ttm drm_dp_helper drm_kms_helper nvme mpt3sas nvme_core xhci_pci raid_class drm xhci_pci_renesas
 CPU: 3 PID: 1707 Comm: systemd-udevd Not tainted 5.17.0-next-20220331-00004-g2d550916a6b9 #51
 pstate: 104000c9 (nzcV daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __lock_acquire
 lr : lock_acquire.part.0
 sp : ffff800030a16fd0
 x29: ffff800030a16fd0 x28: ffffdd876c4e9f90 x27: 0000000000000018
 x26: 0000000000000000 x25: 0000000000000018 x24: 0000000000000000
 x23: ffff08022beacf00 x22: ffffdd8772507660 x21: 0000000000000000
 x20: 0000000000000000 x19: 0000000000000000 x18: ffffdd8772417d2c
 x17: ffffdd876c5bc2e0 x16: 1fffe100457d5b06 x15: 0000000000000094
 x14: 000000000000f1f1 x13: 00000000f3f3f3f3 x12: ffff08022beacf08
 x11: 1ffffbb0ee482fa5 x10: ffffdd8772417d28 x9 : 0000000000000000
 x8 : 0000000000000003 x7 : ffffdd876c4e9f90 x6 : 0000000000000000
 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
 x2 : 0000000000000000 x1 : 0000000000000003 x0 : dfff800000000000
 Call trace:
  __lock_acquire
  lock_acquire.part.0
  lock_acquire
  _raw_spin_lock
  page_vma_mapped_walk
  try_to_migrate_one
  rmap_walk_anon
  try_to_migrate
  __unmap_and_move
  unmap_and_move
  migrate_pages
  migrate_misplaced_page
  do_huge_pmd_numa_page
  __handle_mm_fault
  handle_mm_fault
  do_translation_fault
  do_mem_abort
  el0_da
  el0t_64_sync_handler
  el0t_64_sync
 Code: d65f03c0 d343ff61 d2d00000 f2fbffe0 (38e06820)
 ---[ end trace 0000000000000000 ]---
 Kernel panic - not syncing: Oops: Fatal exception
 SMP: stopping secondary CPUs
 Kernel Offset: 0x5d8763da0000 from 0xffff800008000000
 PHYS_OFFSET: 0x80000000
 CPU features: 0x000,00085c0d,19801c82
 Memory Limit: none
 ---[ end Kernel panic - not syncing: Oops: Fatal exception ]---
> 
> v5:
> - Collect Reviewed-by from Dan Williams.
> - Fix panic reported by kernel test robot <oliver.sang@intel.com>.
> - Remove pmdpp parameter from follow_invalidate_pte() and fold it into follow_pte().
> 
> v4:
> - Fix compilation error on riscv.
> 
> v3:
> - Based on next-20220225.
> 
> v2:
> - Avoid the overly long line in lots of places suggested by Christoph.
> - Fix a compiler warning reported by kernel test robot since pmd_pfn()
>   is not defined when !CONFIG_TRANSPARENT_HUGEPAGE on powerpc architecture.
> - Split a new patch 4 for preparation of fixing the dax bug.
> 
> Muchun Song (6):
>   mm: rmap: fix cache flush on THP pages
>   dax: fix cache flush on PMD-mapped pages
>   mm: rmap: introduce pfn_mkclean_range() to cleans PTEs
>   mm: pvmw: add support for walking devmap pages
>   dax: fix missing writeprotect the pte entry
>   mm: simplify follow_invalidate_pte()
> 
>  fs/dax.c             | 82 +++++-----------------------------------------------
>  include/linux/mm.h   |  3 --
>  include/linux/rmap.h |  3 ++
>  mm/internal.h        | 26 +++++++++++------
>  mm/memory.c          | 81 +++++++++++++++------------------------------------
>  mm/page_vma_mapped.c | 16 +++++-----
>  mm/rmap.c            | 68 +++++++++++++++++++++++++++++++++++--------
>  7 files changed, 114 insertions(+), 165 deletions(-)
> 
> -- 
> 2.11.0
>