Message-ID: <67f94057.050a0220.2c5fcf.0001.GAE@google.com>
Date: Fri, 11 Apr 2025 09:16:23 -0700
From: syzbot <syzbot+ad86dcdffd6785f56e03@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] kernel BUG in ext4_ext_insert_extent (2)

Hello,

syzbot found the following issue on:

HEAD commit:    0af2f6be1b42 Linux 6.15-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17198c04580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f175b153b655dbb3
dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1d71d1bf77d/disk-0af2f6be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7f1638f065da/vmlinux-0af2f6be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9b3e49834705/bzImage-0af2f6be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad86dcdffd6785f56e03@...kaller.appspotmail.com

EXT4-fs error (device loop3): mb_free_blocks:1945: group 0, inode 19: block 289:freeing already freed block (bit 18); block bitmap corrupt.
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2151!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6611 Comm: syz.3.178 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:ext4_ext_insert_extent+0x317c/0x4610 fs/ext4/extents.c:2151
Code: 8b 74 24 60 e8 c5 ab ff ff 48 89 04 24 e9 2c da ff ff e8 97 40 4c ff 41 8d 9c 1c 00 80 ff ff e9 be ee ff ff e8 85 40 4c ff 90 <0f> 0b e8 7d 40 4c ff 44 01 e3 e9 1f f1 ff ff e8 70 40 4c ff 01 dd
RSP: 0018:ffffc900049ff0f0 EFLAGS: 00010287
RAX: 000000000004b428 RBX: ffff88807e54ec30 RCX: ffffc9000c50b000
RDX: 0000000000080000 RSI: ffffffff826efc8b RDI: 0000000000000004
RBP: ffff88804d74c418 R08: 0000000000000004 R09: 0000000000000028
R10: 0000000000000028 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000028 R14: 0000000000000054 R15: ffff888053f4dc18
FS:  00007fe2885d66c0(0000) GS:ffff8881249b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3080cff8 CR3: 000000005ea0a000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_ext_map_blocks+0x205b/0x5d60 fs/ext4/extents.c:4400
 ext4_map_create_blocks fs/ext4/inode.c:519 [inline]
 ext4_map_blocks+0x45b/0x1390 fs/ext4/inode.c:705
 _ext4_get_block+0x24e/0x5a0 fs/ext4/inode.c:784
 ext4_get_block_unwritten+0x29/0x110 fs/ext4/inode.c:817
 ext4_block_write_begin+0x3fb/0xf40 fs/ext4/inode.c:1066
 ext4_write_begin+0x670/0x11f0 fs/ext4/inode.c:1221
 ext4_da_write_begin+0x29d/0x990 fs/ext4/inode.c:2931
 generic_perform_write+0x3d0/0x930 mm/filemap.c:4102
 ext4_buffered_write_iter+0x119/0x440 fs/ext4/file.c:299
 ext4_file_write_iter+0xa4c/0x1d10 fs/ext4/file.c:718
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x5bd/0x1180 fs/read_write.c:684
 ksys_write+0x12a/0x240 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe28778d169
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe2885d6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe2879a5fa0 RCX: 00007fe28778d169
RDX: 000000000000fcb8 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007fe28780e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe2879a5fa0 R15: 00007ffee8100088
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_insert_extent+0x317c/0x4610 fs/ext4/extents.c:2151
Code: 8b 74 24 60 e8 c5 ab ff ff 48 89 04 24 e9 2c da ff ff e8 97 40 4c ff 41 8d 9c 1c 00 80 ff ff e9 be ee ff ff e8 85 40 4c ff 90 <0f> 0b e8 7d 40 4c ff 44 01 e3 e9 1f f1 ff ff e8 70 40 4c ff 01 dd
RSP: 0018:ffffc900049ff0f0 EFLAGS: 00010287
RAX: 000000000004b428 RBX: ffff88807e54ec30 RCX: ffffc9000c50b000
RDX: 0000000000080000 RSI: ffffffff826efc8b RDI: 0000000000000004
RBP: ffff88804d74c418 R08: 0000000000000004 R09: 0000000000000028
R10: 0000000000000028 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000028 R14: 0000000000000054 R15: ffff888053f4dc18
FS:  00007fe2885d66c0(0000) GS:ffff8881249b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb70b406378 CR3: 000000005ea0a000 CR4: 0000000000350ef0


---
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