EXT4-fs (loop4): pa ffff888114d36738: logic 64, phys. 192, len 4
EXT4-fs error (device loop4): ext4_mb_release_inode_pa:4894: group 0, free 1, pa_free 3
EXT4-fs (loop4): Remounting filesystem read-only
------------[ cut here ]------------
kernel BUG at fs/ext4/mballoc.c:4867!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 315 Comm: syz.4.5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:ext4_mb_release_inode_pa+0xa73/0xa80 fs/ext4/mballoc.c:4867
Code: e2 07 80 c2 03 38 c2 0f 8c 2c fe ff ff 4c 89 f7 89 cb e8 c0 34 c8 ff 89 d9 e9 1b fe ff ff e8 34 aa 82 ff 0f 0b e8 2d aa 82 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000dbbe940 EFLAGS: 00010283

RAX: ffffffff81eebc13 RBX: 0000000000000100 RCX: 0000000000080000
RDX: ffffc900031e1000 RSI: 0000000000007757 RDI: 0000000000007758
RBP: ffffc9000dbbea90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001b77d44 R12: 1ffff92001b77d40
R13: dffffc0000000000 R14: 0000000000000010 R15: 0000000000000000
FS:  00007f6941b416c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe0daf8f130 CR3: 000000013223a000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_mb_discard_group_preallocations+0xbdb/0xe20 fs/ext4/mballoc.c:5013
 ext4_mb_discard_preallocations fs/ext4/mballoc.c:5582 [inline]
 ext4_mb_discard_preallocations_should_retry+0x15a/0x5e0 fs/ext4/mballoc.c:5603
 ext4_mb_new_blocks+0x2f60/0x4070 fs/ext4/mballoc.c:5806
 ext4_ext_map_blocks+0x16b5/0x60e0 fs/ext4/extents.c:4346
 ext4_map_blocks+0x9d1/0x1a80 fs/ext4/inode.c:681
 _ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:824
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:857
 ext4_block_write_begin+0x59b/0x1240 fs/ext4/inode.c:1126
 ext4_write_begin+0x614/0xfc0 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x3ed/0x880 fs/ext4/inode.c:3003
 generic_perform_write+0x32d/0x740 mm/filemap.c:3915
 ext4_buffered_write_iter+0x38f/0x690 fs/ext4/file.c:285
 ext4_file_write_iter+0x4b2/0x1540 fs/ext4/file.c:-1
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x65a/0xb30 fs/read_write.c:861
 vfs_writev+0x339/0x5f0 fs/read_write.c:934
 do_pwritev fs/read_write.c:1031 [inline]
 __do_sys_pwritev2 fs/read_write.c:1090 [inline]
 __se_sys_pwritev2+0x17d/0x290 fs/read_write.c:1081
 __x64_sys_pwritev2+0xbf/0xd0 fs/read_write.c:1081
 x64_sys_call+0x2d6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6940b9de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6941b41028 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f6940e25fa0 RCX: 00007f6940b9de99
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 000000000000000b
RBP: 00007f6940c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 00000000007ffffe R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6940e26038 R14: 00007f6940e25fa0 R15: 00007ffc405b8bd8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_mb_release_inode_pa+0xa73/0xa80 fs/ext4/mballoc.c:4867
Code: e2 07 80 c2 03 38 c2 0f 8c 2c fe ff ff 4c 89 f7 89 cb e8 c0 34 c8 ff 89 d9 e9 1b fe ff ff e8 34 aa 82 ff 0f 0b e8 2d aa 82 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000dbbe940 EFLAGS: 00010283
RAX: ffffffff81eebc13 RBX: 0000000000000100 RCX: 0000000000080000
RDX: ffffc900031e1000 RSI: 0000000000007757 RDI: 0000000000007758
RBP: ffffc9000dbbea90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001b77d44 R12: 1ffff92001b77d40
R13: dffffc0000000000 R14: 0000000000000010 R15: 0000000000000000
FS:  00007f6941b416c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe0daf8f130 CR3: 000000013223a000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400