Hello, syzbot found the following issue on: HEAD commit: e33c4963bf53 Merge tag 'nfsd-6.9-5' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=118f2c08980000 kernel config: https://syzkaller.appspot.com/x/.config?x=19891bd776e81b8b dashboard link: https://syzkaller.appspot.com/bug?extid=dbc44fd848d570fc1526 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-e33c4963.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/af334172fdbc/vmlinux-e33c4963.xz kernel image: https://storage.googleapis.com/syzbot-assets/9c0bfbadd1ab/bzImage-e33c4963.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+dbc44fd848d570fc1526@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ bad 1 @0 page 0 0 WARNING: CPU: 0 PID: 14804 at fs/netfs/buffered_write.c:653 netfs_pages_written_back+0xe02/0x1320 fs/netfs/buffered_write.c:653 Modules linked in: CPU: 0 PID: 14804 Comm: syz-executor.2 Not tainted 6.9.0-rc5-syzkaller-00053-ge33c4963bf53 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:netfs_pages_written_back+0xe02/0x1320 fs/netfs/buffered_write.c:653 Code: 48 c1 ee 03 80 3c 06 00 0f 85 d0 04 00 00 48 8b 44 24 18 4d 89 f0 48 c7 c7 80 54 22 8b 48 8b b0 28 01 00 00 e8 8f 0a 21 ff 90 <0f> 0b 90 90 e9 3c f4 ff ff e8 c0 35 5e ff e8 9b cc 44 ff 31 ff 41 RSP: 0018:ffffc900030a75b8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffffea0001522140 RCX: ffffffff81513b29 RDX: ffff88801e1c2440 RSI: ffffffff81513b36 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: dffffc0000000000 R13: ffff88801fa60040 R14: 0000000000000000 R15: ffff88801fa60138 FS: 0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5ed1b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000eda8fda4 CR3: 00000000468b6000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 00000000872c9164 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> netfs_cleanup_buffered_write+0x7a8/0x9b0 fs/netfs/buffered_write.c:726 netfs_write_terminated+0x3c7/0x910 fs/netfs/output.c:121 netfs_end_writethrough+0x1a6/0x200 fs/netfs/output.c:468 netfs_perform_write+0x1a6c/0x26b0 fs/netfs/buffered_write.c:398 netfs_buffered_write_iter_locked+0x213/0x2c0 fs/netfs/buffered_write.c:454 netfs_file_write_iter+0x1e0/0x470 fs/netfs/buffered_write.c:493 v9fs_file_write_iter+0xa1/0x100 fs/9p/vfs_file.c:407 call_write_iter include/linux/fs.h:2110 [inline] do_iter_readv_writev+0x504/0x780 fs/read_write.c:741 vfs_writev+0x36f/0xdb0 fs/read_write.c:971 do_pwritev+0x1b2/0x260 fs/read_write.c:1072 __do_compat_sys_pwritev2 fs/read_write.c:1218 [inline] __se_compat_sys_pwritev2 fs/read_write.c:1210 [inline] __ia32_compat_sys_pwritev2+0x121/0x1b0 fs/read_write.c:1210 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7300579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f5ed15ac EFLAGS: 00000292 ORIG_RAX: 000000000000017b RAX: ffffffffffffffda RBX: 0000000000000026 RCX: 0000000020000240 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000015 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi --- 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. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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
