Re: [PATCH v7 00/70] Introducing the Maple Tree

Yu Zhao
2022-04-16T04:11:01Z

On Fri, Apr 15, 2022 at 7:03 PM Liam Howlett <liam.howlett@oracle.com> wrote:
>
> * Yu Zhao <yuzhao@google.com> [220415 03:11]:
> > On Thu, Apr 14, 2022 at 12:19:11PM -0700, Andrew Morton wrote:
> > > On Thu, 14 Apr 2022 17:15:26 +0000 Liam Howlett <liam.howlett@oracle.com> wrote:
> > >
> > > > > Also I noticed, for the end address to walk_page_range(), Matthew used
> > > > > -1 and you used ULONG_MAX in the maple branch; Andrew used TASK_SIZE
> > > > > below. Having a single value throughout would be great.
> > > >
> > > > I think ULONG_MAX would be best, we should probably change the below to
> > > > ULONG_MAX.
> > >
> > > I switched it to ULONG_MAX/
> > >
> > > > I don't see the code below in mglru-mapletree (62dd11ea8d). Am I on the
> > > > right branch/commit?
> > >
> > > oop, sorry, sleepy guy failed to include all the mglru patches! It
> > > should be fixed now (4e03b8e70232).
> >
> > Hi Liam,
> >
> > Mind taking a look? Thanks.
> >
> > I used
> > 1fe4e0d45c05 (HEAD) mm/vmscan: remove obsolete comment in get_scan_count
> >
> > On aarch64:
> > arch/arm64/kernel/elfcore.c:120:2: error: no member named 'mmap' in 'struct mm_struct'
> > arch/arm64/kernel/elfcore.c:120:2: error: no member named 'vm_next' in 'struct vm_area_struct'
> > arch/arm64/kernel/elfcore.c:130:2: error: no member named 'mmap' in 'struct mm_struct'
> > arch/arm64/kernel/elfcore.c:130:2: error: no member named 'vm_next' in 'struct vm_area_struct'
> > arch/arm64/kernel/elfcore.c:13:23: note: expanded from macro 'for_each_mte_vma'
> > arch/arm64/kernel/elfcore.c:13:45: note: expanded from macro 'for_each_mte_vma'
> > arch/arm64/kernel/elfcore.c:85:2: error: no member named 'mmap' in 'struct mm_struct'
> > arch/arm64/kernel/elfcore.c:85:2: error: no member named 'vm_next' in 'struct vm_area_struct'
> > arch/arm64/kernel/elfcore.c:95:2: error: no member named 'mmap' in 'struct mm_struct'
> > arch/arm64/kernel/elfcore.c:95:2: error: no member named 'vm_next' in 'struct vm_area_struct'
>
> This was fixed in linux-next by commit 3a4f7ef4bed5 [1]. Using the same
> patch fixes this issue, although I will clean up the define prior to
> inclusion in the patches.

Thanks. With that commit, I was able to build and test on aarch64:

==================================================================
BUG: KASAN: invalid-access in mas_destroy+0x10a4/0x126c
Read of size 8 at addr 7bffff8015c1a110 by task CompositorTileW/9966
Pointer tag: [7b], memory tag: [fe]

CPU: 1 PID: 9966 Comm: CompositorTileW Not tainted 5.18.0-rc2-mm1-lockdep+ #2
Call trace:
dump_backtrace+0x1a0/0x200
show_stack+0x24/0x30
dump_stack_lvl+0x7c/0xa0
print_report+0x15c/0x524
kasan_report+0x84/0xb4
kasan_tag_mismatch+0x28/0x3c
__hwasan_tag_mismatch+0x30/0x60
mas_destroy+0x10a4/0x126c
mas_nomem+0x40/0xf4
mas_store_gfp+0x9c/0xfc
do_mas_align_munmap+0x344/0x688
do_mas_munmap+0xf8/0x118
__vm_munmap+0x154/0x1e0
__arm64_sys_munmap+0x44/0x54
el0_svc_common+0xfc/0x1cc
do_el0_svc_compat+0x38/0x5c
el0_svc_compat+0x68/0x118
el0t_32_sync_handler+0xc0/0xf0
el0t_32_sync+0x190/0x194

Allocated by task 9966:
kasan_set_track+0x4c/0x7c
__kasan_slab_alloc+0x84/0xa8
kmem_cache_alloc_bulk+0x300/0x408
mas_alloc_nodes+0x188/0x268
mas_nomem+0x88/0xf4
mas_store_gfp+0x9c/0xfc
do_mas_align_munmap+0x344/0x688
do_mas_munmap+0xf8/0x118
__vm_munmap+0x154/0x1e0
__arm64_sys_munmap+0x44/0x54
el0_svc_common+0xfc/0x1cc
do_el0_svc_compat+0x38/0x5c
el0_svc_compat+0x68/0x118
el0t_32_sync_handler+0xc0/0xf0
el0t_32_sync+0x190/0x194

Freed by task 9966:
kasan_set_track+0x4c/0x7c
kasan_set_free_info+0x2c/0x38
____kasan_slab_free+0x13c/0x184
__kasan_slab_free+0x14/0x24
slab_free_freelist_hook+0x100/0x1ac
kmem_cache_free_bulk+0x230/0x3b0
mas_destroy+0x10d4/0x126c
mas_nomem+0x40/0xf4
mas_store_gfp+0x9c/0xfc
do_mas_align_munmap+0x344/0x688
do_mas_munmap+0xf8/0x118
__vm_munmap+0x154/0x1e0
__arm64_sys_munmap+0x44/0x54
el0_svc_common+0xfc/0x1cc
do_el0_svc_compat+0x38/0x5c
el0_svc_compat+0x68/0x118
el0t_32_sync_handler+0xc0/0xf0
el0t_32_sync+0x190/0x194

The buggy address belongs to the object at ffffff8015c1a100
which belongs to the cache maple_node of size 256
The buggy address is located 16 bytes inside of
256-byte region [ffffff8015c1a100, ffffff8015c1a200)

The buggy address belongs to the physical page:
page:fffffffe00570600 refcount:1 mapcount:0 mapping:0000000000000000
index:0xa8ffff8015c1ad00 pfn:0x95c18
head:fffffffe00570600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x10200(slab|head|zone=0|kasantag=0x0)
raw: 0000000000010200 6cffff8080030850 fffffffe003ec608 dbffff8080016280
raw: a8ffff8015c1ad00 000000000020001e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffffff8015c19f00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
ffffff8015c1a000: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffffff8015c1a100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
^
ffffff8015c1a200: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
ffffff8015c1a300: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
==================================================================