==================================================================
BUG: KASAN: use-after-free in walk_stackframe+0x11c/0x260 arch/riscv/kernel/stacktrace.c:57
Read of size 8 at addr ffffaf8010f83e70 by task syz-executor.1/2977

CPU: 0 PID: 2977 Comm: syz-executor.1 Not tainted 5.17.0-rc1-syzkaller-00002-g0966d385830d #0
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff8000a228>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:113
[<ffffffff831668cc>] show_stack+0x34/0x40 arch/riscv/kernel/stacktrace.c:119
[<ffffffff831756ba>] __dump_stack lib/dump_stack.c:88 [inline]
[<ffffffff831756ba>] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:106
[<ffffffff8047479e>] print_address_description.constprop.0+0x2a/0x330 mm/kasan/report.c:255
[<ffffffff80474d4c>] __kasan_report mm/kasan/report.c:442 [inline]
[<ffffffff80474d4c>] kasan_report+0x184/0x1e0 mm/kasan/report.c:459
[<ffffffff80475b20>] check_region_inline mm/kasan/generic.c:183 [inline]
[<ffffffff80475b20>] __asan_load8+0x6e/0x96 mm/kasan/generic.c:256
[<ffffffff8000a052>] walk_stackframe+0x11c/0x260 arch/riscv/kernel/stacktrace.c:57
[<ffffffff8000a4a4>] arch_stack_walk+0x2c/0x3c arch/riscv/kernel/stacktrace.c:146
[<ffffffff80162ac8>] stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
[<ffffffff80473abe>] kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38

The buggy address belongs to the page:
page:ffffaf807ab0ecd8 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x91183
flags: 0x9000000000(section=18|node=0|zone=0)
raw: 0000009000000000 0000000000000100 0000000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
raw: 00000000000007ff
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x500dc0(GFP_USER|__GFP_ZERO|__GFP_ACCOUNT), pid 2038, ts 685218377800, free_ts 689471502300
 __set_page_owner+0x48/0x136 mm/page_owner.c:183
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0xd0/0x10a mm/page_alloc.c:2427
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0x8da/0x12d8 mm/page_alloc.c:4165
 __alloc_pages+0x150/0x3b6 mm/page_alloc.c:5389
 alloc_pages+0x132/0x2a6 mm/mempolicy.c:2271
 pmd_alloc_one include/asm-generic/pgalloc.h:126 [inline]
 __pmd_alloc+0x4e/0x4cc mm/memory.c:4877
 pmd_alloc include/linux/mm.h:2243 [inline]
 copy_pmd_range mm/memory.c:1140 [inline]
 copy_pud_range mm/memory.c:1197 [inline]
 copy_p4d_range mm/memory.c:1221 [inline]
 copy_page_range+0x1e20/0x236c mm/memory.c:1294
 dup_mmap kernel/fork.c:612 [inline]
 dup_mm+0xb5c/0xe10 kernel/fork.c:1451
 copy_mm kernel/fork.c:1503 [inline]
 copy_process+0x25da/0x3c34 kernel/fork.c:2164
 kernel_clone+0xee/0x920 kernel/fork.c:2555
 __do_sys_clone+0xf2/0x12e kernel/fork.c:2672
 sys_clone+0x32/0x44 kernel/fork.c:2640
 ret_from_syscall+0x0/0x2
page last free stack trace:
 __reset_page_owner+0x4a/0xea mm/page_owner.c:142
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x29c/0x45e mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x6a/0x31e mm/page_alloc.c:3404
 free_the_page mm/page_alloc.c:706 [inline]
 __free_pages+0xe2/0x112 mm/page_alloc.c:5474
 free_pages.part.0+0xe0/0xf6 mm/page_alloc.c:5485
 free_pages+0xe/0x18 mm/page_alloc.c:5482
 pmd_free include/asm-generic/pgalloc.h:142 [inline]
 free_pmd_range mm/memory.c:266 [inline]
 free_pud_range mm/memory.c:284 [inline]
 free_p4d_range mm/memory.c:318 [inline]
 free_pgd_range+0x8b0/0xc54 mm/memory.c:398
 free_pgtables+0xf2/0x1c8 mm/memory.c:430
 exit_mmap+0x168/0x412 mm/mmap.c:3179
 __mmput kernel/fork.c:1114 [inline]
 mmput+0xee/0x2c2 kernel/fork.c:1135
 exit_mm kernel/exit.c:507 [inline]
 do_exit+0x6f2/0x18fc kernel/exit.c:793
 do_group_exit+0x90/0x17e kernel/exit.c:935
 __do_sys_exit_group kernel/exit.c:946 [inline]
 __wake_up_parent+0x0/0x4a kernel/exit.c:944
 ret_from_syscall+0x0/0x2

Memory state around the buggy address:
 ffffaf8010f83d00: ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00
 ffffaf8010f83d80: ff ff ff ff 00 00 00 00 00 00 00 00 ff ff ff ff
>ffffaf8010f83e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                             ^
 ffffaf8010f83e80: ff ff ff ff ff ff ff ff f1 f1 f1 f1 00 00 00 f3
 ffffaf8010f83f00: f3 f3 f3 f3 00 00 00 00 ff ff ff ff 00 00 00 00
==================================================================