syzbot has found a reproducer for the following issue on: HEAD commit: 40f92e79b0aa Merge tag 'block-6.16-20250710' of git://git... git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=14314d82580000 kernel config: https://syzkaller.appspot.com/x/.config?x=bd2783a0a99d4ed0 dashboard link: https://syzkaller.appspot.com/bug?extid=ad86dcdffd6785f56e03 compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11ce7a8c580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=152fc68c580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f33b9048bb66/disk-40f92e79.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/1194a16e19e9/vmlinux-40f92e79.xz kernel image: https://storage.googleapis.com/syzbot-assets/bd82e554bd44/bzImage-40f92e79.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/ead6dd3b0e30/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17a760f0580000) The issue was bisected to: commit 665575cff098b696995ddaddf4646a4099941f5e Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Date: Fri Feb 28 20:37:22 2025 +0000 filemap: move prefaulting out of hot write path bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1434a3d4580000 final oops: https://syzkaller.appspot.com/x/report.txt?x=1634a3d4580000 console output: https://syzkaller.appspot.com/x/log.txt?x=1234a3d4580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ad86dcdffd6785f56e03@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 665575cff098 ("filemap: move prefaulting out of hot write path") ------------[ cut here ]------------ kernel BUG at fs/ext4/extents.c:2153! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 5856 Comm: syz-executor355 Not tainted 6.16.0-rc5-syzkaller-00193-g40f92e79b0aa #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153 Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 3c 95 b6 ff e9 99 e7 ff ff e8 a2 3d 55 ff 90 0f 0b e8 9a 3d 55 ff 90 <0f> 0b e8 92 3d 55 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c RSP: 0018:ffffc9000437ec60 EFLAGS: 00010293 RAX: ffffffff826af7b6 RBX: 000000000000001d RCX: ffff88802dd18000 RDX: 0000000000000000 RSI: 000000000000001d RDI: 000000000000001d RBP: ffffc9000437ee10 R08: ffff8880738b3ae7 R09: 1ffff1100e71675c R10: dffffc0000000000 R11: ffffed100e71675d R12: 000000000000001d R13: dffffc0000000000 R14: ffff8880721f643c R15: ffff888027204700 FS: 00007fa4a23966c0(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f42dc5c1000 CR3: 000000003299c000 CR4: 00000000003526f0 Call Trace: <TASK> ext4_ext_map_blocks+0x1792/0x6ac0 fs/ext4/extents.c:4404 ext4_map_create_blocks fs/ext4/inode.c:609 [inline] ext4_map_blocks+0x931/0x18d0 fs/ext4/inode.c:813 _ext4_get_block+0x200/0x4c0 fs/ext4/inode.c:892 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:925 ext4_block_write_begin+0x6f8/0x14b0 fs/ext4/inode.c:1178 ext4_write_begin+0xa4f/0x1680 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x449/0xd20 fs/ext4/inode.c:3057 generic_perform_write+0x2c4/0x910 mm/filemap.c:4112 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299 ext4_dio_write_iter fs/ext4/file.c:613 [inline] ext4_file_write_iter+0x182a/0x1bc0 fs/ext4/file.c:721 do_iter_readv_writev+0x56b/0x7f0 fs/read_write.c:-1 vfs_writev+0x31a/0x960 fs/read_write.c:1057 do_pwritev fs/read_write.c:1153 [inline] __do_sys_pwritev2 fs/read_write.c:1211 [inline] __se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa4a23e16f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa4a2396208 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007fa4a2468648 RCX: 00007fa4a23e16f9 RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000007 RBP: 00007fa4a2468640 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000e7b R11: 0000000000000246 R12: 00007fa4a2435620 R13: 0000200000000140 R14: 00002000000001c0 R15: 0000200000000080 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_ext_insert_extent+0x4ab7/0x4af0 fs/ext4/extents.c:2153 Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c a6 e7 ff ff 48 89 df e8 3c 95 b6 ff e9 99 e7 ff ff e8 a2 3d 55 ff 90 0f 0b e8 9a 3d 55 ff 90 <0f> 0b e8 92 3d 55 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c RSP: 0018:ffffc9000437ec60 EFLAGS: 00010293 RAX: ffffffff826af7b6 RBX: 000000000000001d RCX: ffff88802dd18000 RDX: 0000000000000000 RSI: 000000000000001d RDI: 000000000000001d RBP: ffffc9000437ee10 R08: ffff8880738b3ae7 R09: 1ffff1100e71675c R10: dffffc0000000000 R11: ffffed100e71675d R12: 000000000000001d R13: dffffc0000000000 R14: ffff8880721f643c R15: ffff888027204700 FS: 00007fa4a23966c0(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff12275000 CR3: 000000003299c000 CR4: 00000000003526f0 --- 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.
