Hello, syzbot found the following issue on: HEAD commit: 9d004b2f4fea Merge tag 'cxl-for-5.19' of git://git.kernel... git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=155cc833f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=d5ef46f0e355ceff dashboard link: https://syzkaller.appspot.com/bug?extid=21f1723d24cb1430ec52 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1036d59df00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=110f21ddf00000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=142f7fa7f00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=162f7fa7f00000 console output: https://syzkaller.appspot.com/x/log.txt?x=122f7fa7f00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+21f1723d24cb1430ec52@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor149:3643 blocked for more than 143 seconds. Not tainted 5.18.0-syzkaller-10643-g9d004b2f4fea #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor149 state:D stack:27656 pid: 3643 ppid: 3603 flags:0x00004004 Call Trace: <TASK> context_switch kernel/sched/core.c:5116 [inline] __schedule+0xa00/0x4b30 kernel/sched/core.c:6431 schedule+0xd2/0x1f0 kernel/sched/core.c:6503 fuse_wait_on_page_writeback fs/fuse/file.c:449 [inline] fuse_wait_on_page_writeback+0x11e/0x170 fs/fuse/file.c:445 fuse_launder_folio fs/fuse/file.c:2361 [inline] fuse_launder_folio+0xeb/0x130 fs/fuse/file.c:2351 folio_launder mm/truncate.c:614 [inline] invalidate_inode_pages2_range+0x99a/0xde0 mm/truncate.c:680 fuse_finish_open+0x2fd/0x4d0 fs/fuse/file.c:217 fuse_open_common+0x2f0/0x500 fs/fuse/file.c:256 do_dentry_open+0x4a1/0x11f0 fs/open.c:824 do_open fs/namei.c:3477 [inline] path_openat+0x1c71/0x2910 fs/namei.c:3610 do_filp_open+0x1aa/0x400 fs/namei.c:3637 do_sys_openat2+0x16d/0x4c0 fs/open.c:1254 do_sys_open fs/open.c:1270 [inline] __do_sys_open fs/open.c:1278 [inline] __se_sys_open fs/open.c:1274 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1274 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f7b892293c9 RSP: 002b:00007f7b891b92f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007f7b892b84d8 RCX: 00007f7b892293c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000100 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7b892b84d0 R13: 00007ffc24e5c05f R14: 00007f7b8928514c R15: 0030656c69662f2e </TASK> INFO: task syz-executor149:3644 blocked for more than 143 seconds. Not tainted 5.18.0-syzkaller-10643-g9d004b2f4fea #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor149 state:D stack:28224 pid: 3644 ppid: 3603 flags:0x00004004 Call Trace: <TASK> context_switch kernel/sched/core.c:5116 [inline] __schedule+0xa00/0x4b30 kernel/sched/core.c:6431 schedule+0xd2/0x1f0 kernel/sched/core.c:6503 io_schedule+0xba/0x130 kernel/sched/core.c:8618 folio_wait_bit_common+0x4f2/0xa90 mm/filemap.c:1324 __folio_lock mm/filemap.c:1690 [inline] folio_lock include/linux/pagemap.h:942 [inline] folio_lock include/linux/pagemap.h:938 [inline] __filemap_get_folio+0xca5/0xf00 mm/filemap.c:1962 truncate_inode_pages_range+0x37d/0x1530 mm/truncate.c:378 truncate_inode_pages mm/truncate.c:452 [inline] truncate_pagecache+0x63/0x90 mm/truncate.c:753 fuse_finish_open+0x39b/0x4d0 fs/fuse/file.c:213 fuse_open_common+0x2f0/0x500 fs/fuse/file.c:256 do_dentry_open+0x4a1/0x11f0 fs/open.c:824 do_open fs/namei.c:3477 [inline] path_openat+0x1c71/0x2910 fs/namei.c:3610 do_filp_open+0x1aa/0x400 fs/namei.c:3637 do_sys_openat2+0x16d/0x4c0 fs/open.c:1254 do_sys_open fs/open.c:1270 [inline] __do_sys_creat fs/open.c:1346 [inline] __se_sys_creat fs/open.c:1340 [inline] __x64_sys_creat+0xc9/0x120 fs/open.c:1340 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f7b892293c9 RSP: 002b:00007f7b891982f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f7b892b84e8 RCX: 00007f7b892293c9 RDX: 00007f7b892293c9 RSI: 0000000000000000 RDI: 00000000200001c0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7b892b84e0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7b892b84e0 R13: 00007ffc24e5c05f R14: 00007f7b8928514c R15: 0030656c69662f2e </TASK> Showing all locks held in the system: 2 locks held by pr/ttyS0/16: 1 lock held by khungtaskd/29: #0: ffffffff8bd86860 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491 2 locks held by getty/3282: #0: ffff88814bbdf098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc90002cd62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcea/0x1230 drivers/tty/n_tty.c:2075 2 locks held by syz-executor149/3644: #0: ffff888074660460 (sb_writers#9){.+.+}-{0:0}, at: do_open fs/namei.c:3470 [inline] #0: ffff888074660460 (sb_writers#9){.+.+}-{0:0}, at: path_openat+0x1b3c/0x2910 fs/namei.c:3610 #1: ffff888072ef9c50 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:741 [inline] #1: ffff888072ef9c50 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: fuse_open_common+0x35d/0x500 fs/fuse/file.c:243 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 5.18.0-syzkaller-10643-g9d004b2f4fea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xc22/0xf90 kernel/hung_task.c:378 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 16 Comm: pr/ttyS0 Not tainted 5.18.0-syzkaller-10643-g9d004b2f4fea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:io_serial_in+0x83/0xa0 drivers/tty/serial/8250/8250_port.c:461 Code: 53 1a fd 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 16 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 e8 20 10 67 fd eb a6 e8 49 10 67 fd eb e3 RSP: 0018:ffffc90000157ac0 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff84601dcc RDI: ffffffff908cd3a0 RBP: ffffffff908cd360 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: fffffbfff2119abf R14: fffffbfff2119a76 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe2f39f108 CR3: 00000000237d6000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> serial_in drivers/tty/serial/8250/8250.h:115 [inline] wait_for_xmitr+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:2089 serial8250_console_putchar+0x1d/0x60 drivers/tty/serial/8250/8250_port.c:3310 uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1935 serial8250_console_write+0xa57/0xc30 drivers/tty/serial/8250/8250_port.c:3382 call_console_driver kernel/printk/printk.c:2075 [inline] __console_emit_next_record+0x896/0xa60 kernel/printk/printk.c:2916 console_emit_next_record kernel/printk/printk.c:3721 [inline] printk_kthread_func.cold+0x702/0x73d kernel/printk/printk.c:3837 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> ---------------- Code disassembly (best guess): 0: 53 push %rbx 1: 1a fd sbb %ch,%bh 3: 48 8d 7d 40 lea 0x40(%rbp),%rdi 7: 44 89 e1 mov %r12d,%ecx a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 11: fc ff df 14: 48 89 fa mov %rdi,%rdx 17: d3 e3 shl %cl,%ebx 19: 48 c1 ea 03 shr $0x3,%rdx 1d: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 21: 75 16 jne 0x39 23: 66 03 5d 40 add 0x40(%rbp),%bx 27: 89 da mov %ebx,%edx 29: ec in (%dx),%al * 2a: 5b pop %rbx <-- trapping instruction 2b: 0f b6 c0 movzbl %al,%eax 2e: 5d pop %rbp 2f: 41 5c pop %r12 31: c3 retq 32: e8 20 10 67 fd callq 0xfd671057 37: eb a6 jmp 0xffffffdf 39: e8 49 10 67 fd callq 0xfd671087 3e: eb e3 jmp 0x23 --- 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 syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
