kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 13547 Comm: syz-executor.5 Not tainted 5.4.0-rc6-next-20191108 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2410 [inline]
RIP: 0010:ext4_writepages+0x17fa/0x2f90 fs/ext4/inode.c:2764
Code: ff ff e8 69 90 b0 ff 48 8b 85 30 fe ff ff 48 8b 8d 00 fe ff ff 48 8d 78 10 48 89 fa 48 c1 ea 03 0f b6 89 c2 00 00 00 48 d3 e3 <42> 80 3c 2a 00 0f 85 be 16 00 00 48 89 58 10 48 c7 c0 a8 b9 c4 89
RSP: 0018:ffff88805c11f410 EFLAGS: 00010206
RAX: fffffffffffffff4 RBX: 000000000080f000 RCX: 000000000000000c
RDX: 0000000000000000 RSI: ffffffff8205686d RDI: 0000000000000004
RBP: ffff88805c11f640 R08: 0000000000000000 R09: ffffed1015d26b7d
R10: ffffed1015d26b7c R11: ffff8880ae935be3 R12: ffff888215948000
R13: dffffc0000000000 R14: 00000000000007ff R15: ffff88808c496588
FS:  00007fec35514700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000960004 CR3: 0000000091697000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x2bc/0x3b0 mm/filemap.c:421
 file_write_and_wait_range+0x175/0x210 mm/filemap.c:782
 ext4_sync_file+0x466/0x1590 fs/ext4/fsync.c:153
 vfs_fsync_range+0x141/0x230 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2860 [inline]
 ext4_buffered_write_iter+0x30a/0x460 fs/ext4/file.c:259
 ext4_dio_write_iter fs/ext4/file.c:455 [inline]
 ext4_file_write_iter+0x76f/0x1770 fs/ext4/file.c:545
 call_write_iter include/linux/fs.h:1902 [inline]
 aio_write+0x2f2/0x540 fs/aio.c:1580
 __io_submit_one fs/aio.c:1812 [inline]
 io_submit_one+0x1008/0x2ee0 fs/aio.c:1859
 __do_sys_io_submit fs/aio.c:1918 [inline]
 __se_sys_io_submit fs/aio.c:1888 [inline]
 __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1888
 ? 0xffffffff81000000
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a219
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:00007fec35513c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007fec35513c90 RCX: 000000000045a219
RDX: 0000000020000540 RSI: 00000000200002f1 RDI: 00007fec354f3000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fec355146d4
R13: 00000000004c18fc R14: 00000000004d5500 R15: 0000000000000006
Modules linked in:
---[ end trace 5aa3786596b09971 ]---
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2410 [inline]
RIP: 0010:ext4_writepages+0x17fa/0x2f90 fs/ext4/inode.c:2764
Code: ff ff e8 69 90 b0 ff 48 8b 85 30 fe ff ff 48 8b 8d 00 fe ff ff 48 8d 78 10 48 89 fa 48 c1 ea 03 0f b6 89 c2 00 00 00 48 d3 e3 <42> 80 3c 2a 00 0f 85 be 16 00 00 48 89 58 10 48 c7 c0 a8 b9 c4 89
RSP: 0018:ffff88805c11f410 EFLAGS: 00010206
RAX: fffffffffffffff4 RBX: 000000000080f000 RCX: 000000000000000c
RDX: 0000000000000000 RSI: ffffffff8205686d RDI: 0000000000000004
RBP: ffff88805c11f640 R08: 0000000000000000 R09: ffffed1015d26b7d
R10: ffffed1015d26b7c R11: ffff8880ae935be3 R12: ffff888215948000
R13: dffffc0000000000 R14: 00000000000007ff R15: ffff88808c496588
FS:  00007fec35514700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000091697000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400