syzbot

loop0: detected capacity change from 0 to 32768
BUG at fs/jfs/jfs_dmap.c:2933 assert(n < 4)
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kernel BUG at fs/jfs/jfs_dmap.c:2933!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3613 Comm: syz-executor184 Not tainted 6.0.0-syzkaller-06205-gffb39098bf87 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:dbFindLeaf+0x154/0x260 fs/jfs/jfs_dmap.c:2933
Code: fe 83 fb 04 75 89 e8 bb 98 a1 fe 48 c7 c1 80 9b 29 8a ba 75 0b 00 00 48 c7 c6 c0 99 29 8a 48 c7 c7 00 9a 29 8a e8 6b 20 66 06 <0f> 0b e8 95 98 a1 fe 41 83 ef 01 31 ff 8d 04 ad 01 00 00 00 44 89
RSP: 0018:ffffc90003c8f490 EFLAGS: 00010282
RAX: 000000000000002b RBX: 0000000000000004 RCX: 0000000000000000
RDX: ffff8880268b1d80 RSI: ffffffff8160f738 RDI: fffff52000791e84
RBP: 000000000000001c R08: 000000000000002b R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffff888026398010
R13: 0000000000000000 R14: 00000000ffffffff R15: 00000000001cb702
FS:  0000555555e39300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdb8738fd0 CR3: 000000001c9ba000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 dbAllocDmapLev+0xa3/0x2c0 fs/jfs/jfs_dmap.c:1937
 dbAlloc+0x804/0xa70 fs/jfs/jfs_dmap.c:825
 extBalloc fs/jfs/jfs_extent.c:321 [inline]
 extAlloc+0x4e7/0xeb0 fs/jfs/jfs_extent.c:122
 jfs_get_block+0x661/0xa90 fs/jfs/inode.c:248
 __block_write_begin_int+0x3ca/0x1520 fs/buffer.c:2006
 __block_write_begin fs/buffer.c:2056 [inline]
 block_write_begin+0xb5/0x4d0 fs/buffer.c:2117
 jfs_write_begin+0x2d/0xd0 fs/jfs/inode.c:304
 generic_perform_write+0x246/0x560 mm/filemap.c:3738
 __generic_file_write_iter+0x2aa/0x4d0 mm/filemap.c:3866
 generic_file_write_iter+0xdf/0x350 mm/filemap.c:3898
 call_write_iter include/linux/fs.h:2187 [inline]
 do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735
 do_iter_write+0x182/0x700 fs/read_write.c:861
 vfs_writev+0x1aa/0x630 fs/read_write.c:934
 do_writev+0x133/0x2f0 fs/read_write.c:977
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6dda2c8e69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd533663f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f6dda2c8e69
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007f6dda288630 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000f8008000
R13: 0000000000000000 R14: 00080000000000f8 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindLeaf+0x154/0x260 fs/jfs/jfs_dmap.c:2933
Code: fe 83 fb 04 75 89 e8 bb 98 a1 fe 48 c7 c1 80 9b 29 8a ba 75 0b 00 00 48 c7 c6 c0 99 29 8a 48 c7 c7 00 9a 29 8a e8 6b 20 66 06 <0f> 0b e8 95 98 a1 fe 41 83 ef 01 31 ff 8d 04 ad 01 00 00 00 44 89
RSP: 0018:ffffc90003c8f490 EFLAGS: 00010282
RAX: 000000000000002b RBX: 0000000000000004 RCX: 0000000000000000
RDX: ffff8880268b1d80 RSI: ffffffff8160f738 RDI: fffff52000791e84
RBP: 000000000000001c R08: 000000000000002b R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffff888026398010
R13: 0000000000000000 R14: 00000000ffffffff R15: 00000000001cb702
FS:  0000555555e39300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b0f7f5e898 CR3: 000000001c9ba000 CR4: 0000000000350ee0