BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1d2c09067 P4D 1d2c09067 PUD 1d547a067 PMD 0 
Oops: 0000 [#1] SMP KASAN
CPU: 0 PID: 3675 Comm: syz-executor.0 Not tainted 5.6.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x42/0x60 kernel/kcov.c:202
Code: 34 24 74 0e 80 e6 01 74 34 80 b8 d4 12 00 00 00 74 2b 8b 90 b0 12 00 00 83 fa 02 75 20 48 8b 88 b8 12 00 00 8b 80 b4 12 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 2e
RSP: 0018:ffff8881d0f8f890 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8881d0f8f980 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff858c7c70 RDI: 0000000000000005
RBP: 0000000000000001 R08: ffff8881c4c43100 R09: ffffed103b646a8c
R10: ffffed103b646a8b R11: ffff8881db23545b R12: ffff8881a8d039c2
R13: ffff8881d0f8f998 R14: ffff8881cf0abb68 R15: ffff8881a8d039c2
FS:  00007f92db508700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001d91e8000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 xa_is_internal include/linux/xarray.h:169 [inline]
 xa_is_node include/linux/xarray.h:1224 [inline]
 xas_start+0xd0/0x530 lib/xarray.c:189
 xas_load+0x28/0x2c0 lib/xarray.c:233
 find_get_entry+0x13d/0x810 mm/filemap.c:1511
 find_lock_entry+0x2e/0x3a0 mm/filemap.c:1562
 shmem_getpage_gfp.isra.0+0x1bf/0x19e0 mm/shmem.c:1771
 shmem_getpage mm/shmem.c:154 [inline]
 shmem_file_read_iter+0x2bd/0xb20 mm/shmem.c:2565
 call_read_iter include/linux/fs.h:1895 [inline]
 new_sync_read+0x418/0x6d0 fs/read_write.c:414
 __vfs_read+0xc9/0x100 fs/read_write.c:427
 vfs_read+0x1ea/0x430 fs/read_write.c:461
 ksys_read+0x127/0x250 fs/read_write.c:587
 do_syscall_64+0xb6/0x5a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f92db507c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f92db5086d4 RCX: 000000000045c849
RDX: 00000000ffffffad RSI: 0000000020003200 RDI: 0000000000000005
RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000087b R14: 00000000004cb31a R15: 000000000076bfac
Modules linked in:
CR2: 0000000000000000
---[ end trace b2d8a6bf495c71a7 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x42/0x60 kernel/kcov.c:202
Code: 34 24 74 0e 80 e6 01 74 34 80 b8 d4 12 00 00 00 74 2b 8b 90 b0 12 00 00 83 fa 02 75 20 48 8b 88 b8 12 00 00 8b 80 b4 12 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 2e
RSP: 0018:ffff8881d0f8f890 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8881d0f8f980 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff858c7c70 RDI: 0000000000000005
RBP: 0000000000000001 R08: ffff8881c4c43100 R09: ffffed103b646a8c
R10: ffffed103b646a8b R11: ffff8881db23545b R12: ffff8881a8d039c2
R13: ffff8881d0f8f998 R14: ffff8881cf0abb68 R15: ffff8881a8d039c2
FS:  00007f92db508700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001d91e8000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400