Hello, syzbot found the following issue on: HEAD commit: ee9a43b7cfe2 Merge tag 'net-6.11-rc3' of git://git.kernel... git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=1655c15d980000 kernel config: https://syzkaller.appspot.com/x/.config?x=9358cc4a2e37fd30 dashboard link: https://syzkaller.appspot.com/bug?extid=1ad8bac5af24d01e2cbd compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15a8fbc9980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17bc726d980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/e6062f24de48/disk-ee9a43b7.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/5d3ec6153dbd/vmlinux-ee9a43b7.xz kernel image: https://storage.googleapis.com/syzbot-assets/98dbabb91d02/bzImage-ee9a43b7.xz mounted in repro #1: https://storage.googleapis.com/syzbot-assets/4dd4c0acf870/mount_0.gz mounted in repro #2: https://storage.googleapis.com/syzbot-assets/ca52271baf46/mount_1.gz The issue was bisected to: commit 1f6bc02f18489b9c9ea39b068d0695fb0e4567e9 Author: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx> Date: Fri Dec 15 11:19:50 2023 +0000 ext4: fallback to complex scan if aligned scan doesn't work bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=118a3d11980000 final oops: https://syzkaller.appspot.com/x/report.txt?x=138a3d11980000 console output: https://syzkaller.appspot.com/x/log.txt?x=158a3d11980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1ad8bac5af24d01e2cbd@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 1f6bc02f1848 ("ext4: fallback to complex scan if aligned scan doesn't work") EXT4-fs: Ignoring removed oldalloc option EXT4-fs (loop0): re-mounted 00000000-0000-0000-0000-000000000000 r/w. Quota mode: none. Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 UID: 0 PID: 5224 Comm: syz-executor196 Not tainted 6.11.0-rc2-syzkaller-00111-gee9a43b7cfe2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:ext4_mb_regular_allocator+0x1687/0x3b80 fs/ext4/mballoc.c:2932 Code: 16 00 00 8b 1a bf 40 00 00 00 89 de e8 e2 ab 38 ff 48 83 fb 3f 0f 87 9f 19 00 00 e8 93 a7 38 ff 89 d9 49 d3 ec 4c 89 f8 31 d2 <49> f7 f4 48 89 d3 31 ff 48 89 d6 e8 59 ac 38 ff 83 bc 24 64 01 00 RSP: 0018:ffffc9000341e740 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 0000000000000004 RCX: 0000000000000004 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000040 RBP: ffffc9000341e9f0 R08: ffffffff825acf3e R09: ffffffff825bea62 R10: 0000000000000005 R11: ffff8880282b1e00 R12: 0000000000000000 R13: 0000000000000003 R14: ffff8880663270e0 R15: 0000000000000001 FS: 0000555592670380(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe13f0d000 CR3: 0000000025072000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ext4_mb_new_blocks+0x10a8/0x4e30 fs/ext4/mballoc.c:6219 ext4_ext_map_blocks+0x1c74/0x77b0 fs/ext4/extents.c:4318 ext4_map_blocks+0xa5e/0x1d20 fs/ext4/inode.c:652 _ext4_get_block+0x239/0x6b0 fs/ext4/inode.c:794 ext4_get_block_unwritten+0x2f/0x100 fs/ext4/inode.c:827 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2125 ext4_try_to_write_inline_data+0x7ed/0x1360 fs/ext4/inline.c:739 ext4_write_begin+0x2a0/0x10e0 fs/ext4/inode.c:1172 ext4_da_write_begin+0x300/0xa70 fs/ext4/inode.c:2943 generic_perform_write+0x399/0x840 mm/filemap.c:4019 ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299 ext4_file_write_iter+0x1de/0x1a10 do_iter_readv_writev+0x60a/0x890 vfs_writev+0x37c/0xbb0 fs/read_write.c:971 do_pwritev fs/read_write.c:1072 [inline] __do_sys_pwritev2 fs/read_write.c:1131 [inline] __se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1122 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb9c91a61d9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe13f0c6c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007fb9c91ef095 RCX: 00007fb9c91a61d9 RDX: 000000000000000f RSI: 00000000200002c0 RDI: 0000000000000004 RBP: 0031656c69662f2e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000a12 R11: 0000000000000246 R12: 70756f7267647362 R13: 7461785f72657375 R14: 431bde82d7b634db R15: 00007fb9c91ef03b </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_mb_regular_allocator+0x1687/0x3b80 fs/ext4/mballoc.c:2932 Code: 16 00 00 8b 1a bf 40 00 00 00 89 de e8 e2 ab 38 ff 48 83 fb 3f 0f 87 9f 19 00 00 e8 93 a7 38 ff 89 d9 49 d3 ec 4c 89 f8 31 d2 <49> f7 f4 48 89 d3 31 ff 48 89 d6 e8 59 ac 38 ff 83 bc 24 64 01 00 RSP: 0018:ffffc9000341e740 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 0000000000000004 RCX: 0000000000000004 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000040 RBP: ffffc9000341e9f0 R08: ffffffff825acf3e R09: ffffffff825bea62 R10: 0000000000000005 R11: ffff8880282b1e00 R12: 0000000000000000 R13: 0000000000000003 R14: ffff8880663270e0 R15: 0000000000000001 FS: 0000555592670380(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe13f0d000 CR3: 0000000025072000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 00 00 add %al,(%rax) 2: 8b 1a mov (%rdx),%ebx 4: bf 40 00 00 00 mov $0x40,%edi 9: 89 de mov %ebx,%esi b: e8 e2 ab 38 ff call 0xff38abf2 10: 48 83 fb 3f cmp $0x3f,%rbx 14: 0f 87 9f 19 00 00 ja 0x19b9 1a: e8 93 a7 38 ff call 0xff38a7b2 1f: 89 d9 mov %ebx,%ecx 21: 49 d3 ec shr %cl,%r12 24: 4c 89 f8 mov %r15,%rax 27: 31 d2 xor %edx,%edx * 29: 49 f7 f4 div %r12 <-- trapping instruction 2c: 48 89 d3 mov %rdx,%rbx 2f: 31 ff xor %edi,%edi 31: 48 89 d6 mov %rdx,%rsi 34: e8 59 ac 38 ff call 0xff38ac92 39: 83 .byte 0x83 3a: bc 24 64 01 00 mov $0x16424,%esp --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
