do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589
Unable to handle kernel paging request at virtual address dfff800000000003
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff800000000003] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4574 Comm: syz.3.45 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 02400005 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_mb_get_buddy_page_lock fs/ext4/mballoc.c:1380 [inline]
pc : ext4_mb_init_group+0x14c/0x614 fs/ext4/mballoc.c:1440
lr : ext4_mb_get_buddy_page_lock fs/ext4/mballoc.c:1376 [inline]
lr : ext4_mb_init_group+0xf8/0x614 fs/ext4/mballoc.c:1440
sp : ffff800022916a40
x29: ffff800022916a60 x28: 0000000000000018 x27: 0000000000000004
x26: 0000000000000000 x25: 0000000000000400 x24: ffff0000e1855320
x23: 0000000000000000 x22: ffff0000e1b30000 x21: 1fffe0001982c403
x20: ffff0000cc162018 x19: 0000000000000000 x18: 1fffe00033c2177e
x17: 0000000000000000 x16: ffff8000082de324 x15: 0000000000000002
x14: 0000000000000001 x13: 1ffff00002cd02ea x12: 0000000000080000
x11: 000000000004857d x10: ffff80002bd54000 x9 : dfff800000000000
x8 : 0000000000000003 x7 : ffff8000083151e4 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : ffff80000aa9f758
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
dump_backtrace(regs = 000000004b117381 tsk = 0000000000000000)
Call trace:
 ext4_mb_get_buddy_page_lock fs/ext4/mballoc.c:1380 [inline]
 ext4_mb_init_group+0x14c/0x614 fs/ext4/mballoc.c:1440
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2584 [inline]
 ext4_mb_regular_allocator+0xcf8/0x2b60 fs/ext4/mballoc.c:2791
 ext4_mb_new_blocks+0xb78/0x4244 fs/ext4/mballoc.c:5793
 ext4_alloc_branch fs/ext4/indirect.c:340 [inline]
 ext4_ind_map_blocks+0xcc0/0x1d78 fs/ext4/indirect.c:635
 ext4_map_blocks+0x768/0x160c fs/ext4/inode.c:683
 _ext4_get_block+0x198/0x4dc fs/ext4/inode.c:824
 ext4_get_block+0x4c/0x60 fs/ext4/inode.c:841
 __block_write_begin_int+0x3d8/0x13c0 fs/buffer.c:1991
 __block_write_begin+0x7c/0xa0 fs/buffer.c:2041
 ext4_convert_inline_data_to_extent fs/ext4/ext4_jbd2.h:-1 [inline]
 ext4_try_to_write_inline_data+0x6b8/0x11a0 fs/ext4/inline.c:769
 ext4_write_begin+0x234/0x12d4 fs/ext4/inode.c:1206
 generic_perform_write+0x240/0x508 mm/filemap.c:3862
 ext4_buffered_write_iter+0x2c8/0x528 fs/ext4/file.c:292
 ext4_file_write_iter+0x188/0x1500 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2271 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x3c8/0x7c8 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __arm64_sys_pwrite64+0x178/0x210 fs/read_write.c:706
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589
Code: 9100627c d2d00009 d343ff88 f2fbffe9 (38696908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9100627c 	add	x28, x19, #0x18
   4:	d2d00009 	mov	x9, #0x800000000000        	// #140737488355328
   8:	d343ff88 	lsr	x8, x28, #3
   c:	f2fbffe9 	movk	x9, #0xdfff, lsl #48
* 10:	38696908 	ldrb	w8, [x8, x9] <-- trapping instruction