[syzbot] [arm?] KASAN: slab-out-of-bounds Read in contpte_clear_young_dirty_ptes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a4be1ad3a6e Revert "vfs: Delete the associated dentry whe..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17c9f9fc980000
kernel config: https://syzkaller.appspot.com/x/.config?x=92af4362e7016e3e
dashboard link: https://syzkaller.appspot.com/bug?extid=7eaa0d7b9fccf21052f1
compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-4a4be1ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0b7af5f8e955/vmlinux-4a4be1ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5b1adcfe75e6/Image-4a4be1ad.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7eaa0d...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in __ptep_get arch/arm64/include/asm/pgtable.h:315 [inline]
BUG: KASAN: slab-out-of-bounds in __clear_young_dirty_ptes arch/arm64/include/asm/pgtable.h:1309 [inline]
BUG: KASAN: slab-out-of-bounds in contpte_clear_young_dirty_ptes+0x104/0x214 arch/arm64/mm/contpte.c:389
Read of size 8 at addr ffff00000bf420b0 by task syz-executor.0/4197

CPU: 0 PID: 4197 Comm: syz-executor.0 Tainted: G W 6.10.0-rc1-syzkaller-00027-g4a4be1ad3a6e #0
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x9c/0x11c arch/arm64/kernel/stacktrace.c:317
show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:324
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xa4/0xf4 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xf4/0x5a4 mm/kasan/report.c:488
kasan_report+0xc8/0x108 mm/kasan/report.c:601
__asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
__ptep_get arch/arm64/include/asm/pgtable.h:315 [inline]
__clear_young_dirty_ptes arch/arm64/include/asm/pgtable.h:1309 [inline]
contpte_clear_young_dirty_ptes+0x104/0x214 arch/arm64/mm/contpte.c:389
clear_young_dirty_ptes arch/arm64/include/asm/pgtable.h:1715 [inline]
madvise_free_pte_range+0xce8/0x10e0 mm/madvise.c:767
walk_pmd_range mm/pagewalk.c:143 [inline]
walk_pud_range mm/pagewalk.c:221 [inline]
walk_p4d_range mm/pagewalk.c:256 [inline]
walk_pgd_range+0x8e8/0x14a4 mm/pagewalk.c:293
__walk_page_range+0x420/0x5e4 mm/pagewalk.c:395
walk_page_range+0x370/0x6f8 mm/pagewalk.c:521
madvise_free_single_vma+0x300/0x5a8 mm/madvise.c:815
madvise_dontneed_free mm/madvise.c:929 [inline]
madvise_vma_behavior+0x30c/0x1028 mm/madvise.c:1046
madvise_walk_vmas+0x114/0x210 mm/madvise.c:1268
do_madvise+0x20c/0x6c4 mm/madvise.c:1464
__do_sys_madvise mm/madvise.c:1481 [inline]
__se_sys_madvise mm/madvise.c:1479 [inline]
__arm64_sys_madvise+0x88/0xdc mm/madvise.c:1479
__invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
invoke_syscall+0x6c/0x25c arch/arm64/kernel/syscall.c:48
el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:133
do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:152
el0_svc+0x50/0x180 arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Allocated by task 1:
kasan_save_stack+0x3c/0x64 mm/kasan/common.c:47
kasan_save_track+0x20/0x3c mm/kasan/common.c:68
kasan_save_alloc_info+0x40/0x54 mm/kasan/generic.c:565
unpoison_slab_object mm/kasan/common.c:312 [inline]
__kasan_slab_alloc+0x8c/0x90 mm/kasan/common.c:338
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3940 [inline]
slab_alloc_node mm/slub.c:4000 [inline]
kmem_cache_alloc_noprof+0x128/0x2e0 mm/slub.c:4007
__kernfs_new_node+0xd0/0x704 fs/kernfs/dir.c:624
kernfs_new_node+0x100/0x1f0 fs/kernfs/dir.c:700
kernfs_create_dir_ns+0x34/0x118 fs/kernfs/dir.c:1061
internal_create_group+0x2a0/0xb80 fs/sysfs/group.c:167
sysfs_create_group+0x18/0x24 fs/sysfs/group.c:206
dpm_sysfs_add+0x80/0x1c4 drivers/base/power/sysfs.c:702
device_add+0x70c/0x12b8 drivers/base/core.c:3681
platform_device_add+0x2d8/0x5f4 drivers/base/platform.c:716
platform_device_register_full+0x390/0x4f8 drivers/base/platform.c:844
einj_init+0x94/0x110 drivers/acpi/apei/einj-core.c:897
do_one_initcall+0x140/0x7bc init/main.c:1267
do_initcall_level init/main.c:1329 [inline]
do_initcalls init/main.c:1345 [inline]
do_basic_setup init/main.c:1364 [inline]
kernel_init_freeable+0x56c/0xbf4 init/main.c:1578
kernel_init+0x24/0x1e0 init/main.c:1467
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

The buggy address belongs to the object at ffff00000bf42000
which belongs to the cache kernfs_node_cache of size 176
The buggy address is located 0 bytes to the right of
allocated 176-byte region [ffff00000bf42000, ffff00000bf420b0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4bf42
flags: 0x1ffc00000000000(node=0|zone=0|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 01ffc00000000000 ffff00000a14d280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000110011 00000001ffffefff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff00000bf41f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff00000bf42000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff00000bf42080: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00
^
ffff00000bf42100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff00000bf42180: 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 00
==================================================================


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