syzbot

------------[ cut here ]------------
kernel BUG at [] mm/page_table_check.c:118!
Kernel BUG [#1]
Modules linked in:
CPU: 0 UID: 0 PID: 4695 Comm: syz.1.246 Not tainted syzkaller #0 PREEMPT 
Hardware name: riscv-virtio,qemu (DT)
epc : page_table_check_set+0xa74/0xd30 mm/page_table_check.c:118
 ra : page_table_check_set+0xa74/0xd30 mm/page_table_check.c:118
epc : ffffffff80bfcb7c ra : ffffffff80bfcb7c sp : ffff8f8009ce6f50
 gp : ffffffff89f9df20 tp : ffffaf801ae03500 t0 : ffff8f8009ce7ce0
 t1 : fffff5ef026ad009 t2 : ffffffff86806d68 s0 : ffff8f8009ce6fd0
 s1 : 0000000000000001 a0 : 0000000000000001 a1 : 0000000000000000
 a2 : 0000000000080000 a3 : ffffffff80bfcb7c a4 : ffff8f8004935190
 a5 : 000000000002c190 a6 : 0000000000000003 a7 : ffffaf801356804b
 s2 : 00000000000b4800 s3 : 0000000000000000 s4 : ffffaf8013568000
 s5 : 0000000000000200 s6 : 0000000000000001 s7 : dfffffff00000000
 s8 : 0000000000007fff s9 : ffffffff88825fa0 s10: 0000000000000000
 s11: ffffffff8a0b5d80 t3 : 0000000000000001 t4 : fffff5ef026ad009
 t5 : fffff5ef026ad00a t6 : 0000000000000002 ssp : 0000000000000000
status: 0000000200000120 badaddr: ffffffff80bfcb7c cause: 0000000000000003
[<ffffffff80bfcb7c>] page_table_check_set+0xa74/0xd30 mm/page_table_check.c:118
[<ffffffff80bfd300>] __page_table_check_ptes_set+0x264/0x47c mm/page_table_check.c:212
[<ffffffff80b8b0de>] page_table_check_ptes_set include/linux/page_table_check.h:76 [inline]
[<ffffffff80b8b0de>] set_ptes arch/riscv/include/asm/pgtable.h:640 [inline]
[<ffffffff80b8b0de>] __split_huge_pmd_locked mm/huge_memory.c:3252 [inline]
[<ffffffff80b8b0de>] split_huge_pmd_locked+0x2b0a/0x326c mm/huge_memory.c:3270
[<ffffffff80b8bafa>] __split_huge_pmd+0x2ba/0x3e4 mm/huge_memory.c:3284
[<ffffffff809ab772>] zap_pmd_range mm/memory.c:1929 [inline]
[<ffffffff809ab772>] zap_pud_range mm/memory.c:1978 [inline]
[<ffffffff809ab772>] zap_p4d_range mm/memory.c:1999 [inline]
[<ffffffff809ab772>] unmap_page_range+0x23aa/0x408c mm/memory.c:2020
[<ffffffff809ad592>] unmap_single_vma+0x13e/0x230 mm/memory.c:2062
[<ffffffff809add6a>] zap_page_range_single_batched+0x2da/0x548 mm/memory.c:2140
[<ffffffff80ab726c>] madvise_dontneed_single_vma mm/madvise.c:866 [inline]
[<ffffffff80ab726c>] madvise_dontneed_free mm/madvise.c:958 [inline]
[<ffffffff80ab726c>] madvise_vma_behavior+0x1d34/0x251c mm/madvise.c:1370
[<ffffffff80ab7c8e>] madvise_walk_vmas+0x23a/0x970 mm/madvise.c:1721
[<ffffffff80ab85ae>] madvise_do_behavior+0x1ea/0x5c0 mm/madvise.c:1937
[<ffffffff80ab94c6>] do_madvise+0x18a/0x22c mm/madvise.c:2030
[<ffffffff80ab95f0>] __do_sys_madvise mm/madvise.c:2039 [inline]
[<ffffffff80ab95f0>] __se_sys_madvise mm/madvise.c:2037 [inline]
[<ffffffff80ab95f0>] __riscv_sys_madvise+0x88/0xdc mm/madvise.c:2037
[<ffffffff80078192>] syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112
[<ffffffff86391c0a>] do_trap_ecall_u+0x3d2/0x58c arch/riscv/kernel/traps.c:344
[<ffffffff863bb61e>] handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232
Code: 7097 ff90 80e7 4580 81e3 e004 8097 ff90 80e7 9380 (9002) 8097 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	ff907097          	auipc	ra,0xff907
   4:	458080e7          	jalr	1112(ra) # 0xff907458
   8:	e00481e3          	beqz	s1,0xfffffffffffffe0a
   c:	ff908097          	auipc	ra,0xff908
  10:	938080e7          	jalr	-1736(ra) # 0xff907944
* 14:	9002                	ebreak <-- trapping instruction
  16:	9780                	.short	0x8097