Hello, syzbot found the following issue on: HEAD commit: 7b4f2bc91c15 Add linux-next specific files for 20240418 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=15db8e10980000 kernel config: https://syzkaller.appspot.com/x/.config?x=ae644165a243bf62 dashboard link: https://syzkaller.appspot.com/bug?extid=57cc2f20a84cb4346354 compiler: Debian clang version 15.0.6, 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/524a18e6c5be/disk-7b4f2bc9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/029f1b84d653/vmlinux-7b4f2bc9.xz kernel image: https://storage.googleapis.com/syzbot-assets/c02d1542e886/bzImage-7b4f2bc9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+57cc2f20a84cb4346354@xxxxxxxxxxxxxxxxxxxxxxxxx sp0: Synchronizing with TNC ------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc4-next-20240418-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/6662 is trying to acquire lock: ffffffff8e327d60 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1994 [inline] ffffffff8e327d60 (console_owner){....}-{0:0}, at: vprintk_emit+0x3cf/0x770 kernel/printk/printk.c:2344 but task is already holding lock: ffffffff94aa1878 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] ffffffff94aa1878 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x10e/0x320 drivers/tty/serial/serial_core.c:604 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] serial8250_console_write+0x1a8/0x1770 drivers/tty/serial/8250/8250_port.c:3352 console_emit_next_record kernel/printk/printk.c:2928 [inline] console_flush_all+0x867/0xfd0 kernel/printk/printk.c:2994 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3063 vprintk_emit+0x5a6/0x770 kernel/printk/printk.c:2345 _printk+0xd5/0x120 kernel/printk/printk.c:2370 register_console+0x722/0xce0 kernel/printk/printk.c:3596 univ8250_console_init+0x49/0x50 drivers/tty/serial/8250/8250_core.c:723 console_init+0x1b8/0x6f0 kernel/printk/printk.c:3742 start_kernel+0x2d3/0x500 init/main.c:1034 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x147 -> #0 (console_owner){....}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 console_trylock_spinning kernel/printk/printk.c:1994 [inline] vprintk_emit+0x3ec/0x770 kernel/printk/printk.c:2344 _printk+0xd5/0x120 kernel/printk/printk.c:2370 __report_bug lib/bug.c:195 [inline] report_bug+0x346/0x500 lib/bug.c:219 handle_bug+0x3e/0x70 arch/x86/kernel/traps.c:239 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:260 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:605 tnc_init drivers/net/hamradio/6pack.c:531 [inline] sixpack_open+0x790/0xa80 drivers/net/hamradio/6pack.c:628 tty_ldisc_open drivers/tty/tty_ldisc.c:432 [inline] tty_ldisc_reinit+0x2d4/0x4a0 drivers/tty/tty_ldisc.c:661 tty_reopen+0x20b/0x2d0 drivers/tty/tty_io.c:1366 tty_open_by_driver drivers/tty/tty_io.c:2082 [inline] tty_open+0xa26/0xdf0 drivers/tty/tty_io.c:2135 chrdev_open+0x5b0/0x630 fs/char_dev.c:414 do_dentry_open+0x95a/0x1720 fs/open.c:955 do_open fs/namei.c:3650 [inline] path_openat+0x289f/0x3280 fs/namei.c:3807 do_filp_open+0x235/0x490 fs/namei.c:3834 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_openat fs/open.c:1436 [inline] __se_sys_openat fs/open.c:1431 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1431 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** 3 locks held by syz-executor.4/6662: #0: ffff88805f95e1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock_interruptible+0x68/0xc0 drivers/tty/tty_mutex.c:27 #1: ffff88805f95e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:289 [inline] #1: ffff88805f95e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x6c/0xc0 drivers/tty/tty_ldisc.c:313 #2: ffffffff94aa1878 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] #2: ffffffff94aa1878 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x10e/0x320 drivers/tty/serial/serial_core.c:604 stack backtrace: CPU: 0 PID: 6662 Comm: syz-executor.4 Not tainted 6.9.0-rc4-next-20240418-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 console_trylock_spinning kernel/printk/printk.c:1994 [inline] vprintk_emit+0x3ec/0x770 kernel/printk/printk.c:2344 _printk+0xd5/0x120 kernel/printk/printk.c:2370 __report_bug lib/bug.c:195 [inline] report_bug+0x346/0x500 lib/bug.c:219 handle_bug+0x3e/0x70 arch/x86/kernel/traps.c:239 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:260 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 RIP: 0010:uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:605 Code: 74 08 48 89 df e8 a0 9e be fc 48 83 3b 00 74 74 e8 05 4e 59 fc eb 97 e8 fe 4d 59 fc 45 31 e4 eb 08 e8 f4 4d 59 fc 45 31 ed 90 <0f> 0b 90 45 84 e4 74 0a e8 e3 4d 59 fc 45 31 f6 eb 84 e8 d9 4d 59 RSP: 0018:ffffc90009fcf4b8 EFLAGS: 00010046 RAX: ffffffff853d0f92 RBX: dffffc0000000000 RCX: 0000000000040000 RDX: ffffc90013601000 RSI: 000000000001ba5f RDI: 000000000001ba60 RBP: ffff88801f720f48 R08: 0000000000000003 R09: fffff520013f9e74 R10: dffffc0000000000 R11: fffff520013f9e74 R12: 0000000000000000 R13: 0000000000000246 R14: ffff88801f720be8 R15: ffffffff94aa1860 tnc_init drivers/net/hamradio/6pack.c:531 [inline] sixpack_open+0x790/0xa80 drivers/net/hamradio/6pack.c:628 tty_ldisc_open drivers/tty/tty_ldisc.c:432 [inline] tty_ldisc_reinit+0x2d4/0x4a0 drivers/tty/tty_ldisc.c:661 tty_reopen+0x20b/0x2d0 drivers/tty/tty_io.c:1366 tty_open_by_driver drivers/tty/tty_io.c:2082 [inline] tty_open+0xa26/0xdf0 drivers/tty/tty_io.c:2135 chrdev_open+0x5b0/0x630 fs/char_dev.c:414 do_dentry_open+0x95a/0x1720 fs/open.c:955 do_open fs/namei.c:3650 [inline] path_openat+0x289f/0x3280 fs/namei.c:3807 do_filp_open+0x235/0x490 fs/namei.c:3834 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_openat fs/open.c:1436 [inline] __se_sys_openat fs/open.c:1431 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1431 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd50cc7dea9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007fd50d96c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd50cdabf80 RCX: 00007fd50cc7dea9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007fd50ccca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd50cdabf80 R15: 00007ffeacd13b38 </TASK> WARNING: CPU: 0 PID: 6662 at drivers/tty/serial/serial_core.c:605 uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:605 Modules linked in: CPU: 0 PID: 6662 Comm: syz-executor.4 Not tainted 6.9.0-rc4-next-20240418-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:605 Code: 74 08 48 89 df e8 a0 9e be fc 48 83 3b 00 74 74 e8 05 4e 59 fc eb 97 e8 fe 4d 59 fc 45 31 e4 eb 08 e8 f4 4d 59 fc 45 31 ed 90 <0f> 0b 90 45 84 e4 74 0a e8 e3 4d 59 fc 45 31 f6 eb 84 e8 d9 4d 59 RSP: 0018:ffffc90009fcf4b8 EFLAGS: 00010046 RAX: ffffffff853d0f92 RBX: dffffc0000000000 RCX: 0000000000040000 RDX: ffffc90013601000 RSI: 000000000001ba5f RDI: 000000000001ba60 RBP: ffff88801f720f48 R08: 0000000000000003 R09: fffff520013f9e74 R10: dffffc0000000000 R11: fffff520013f9e74 R12: 0000000000000000 R13: 0000000000000246 R14: ffff88801f720be8 R15: ffffffff94aa1860 FS: 00007fd50d96c6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd65b98000 CR3: 0000000011650000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> tnc_init drivers/net/hamradio/6pack.c:531 [inline] sixpack_open+0x790/0xa80 drivers/net/hamradio/6pack.c:628 tty_ldisc_open drivers/tty/tty_ldisc.c:432 [inline] tty_ldisc_reinit+0x2d4/0x4a0 drivers/tty/tty_ldisc.c:661 tty_reopen+0x20b/0x2d0 drivers/tty/tty_io.c:1366 tty_open_by_driver drivers/tty/tty_io.c:2082 [inline] tty_open+0xa26/0xdf0 drivers/tty/tty_io.c:2135 chrdev_open+0x5b0/0x630 fs/char_dev.c:414 do_dentry_open+0x95a/0x1720 fs/open.c:955 do_open fs/namei.c:3650 [inline] path_openat+0x289f/0x3280 fs/namei.c:3807 do_filp_open+0x235/0x490 fs/namei.c:3834 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_openat fs/open.c:1436 [inline] __se_sys_openat fs/open.c:1431 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1431 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd50cc7dea9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007fd50d96c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd50cdabf80 RCX: 00007fd50cc7dea9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007fd50ccca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd50cdabf80 R15: 00007ffeacd13b38 </TASK> --- 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
