Hello, syzbot found the following issue on: HEAD commit: d3fa86b1a7b4 Merge tag 'net-6.7-rc3' of git://git.kernel.o.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=10c3bcd8e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=e32016b84cf917ca dashboard link: https://syzkaller.appspot.com/bug?extid=0015c7d1e68e7f61621d 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=12abdea4e80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=173b1c94e80000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c785fb3c059b/disk-d3fa86b1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/142addbb8256/vmlinux-d3fa86b1.xz kernel image: https://storage.googleapis.com/syzbot-assets/8e6d7e1c7b24/bzImage-d3fa86b1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0015c7d1e68e7f61621d@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: uninit-value in n_tty_lookahead_flow_ctrl+0x2cd/0x2f0 drivers/tty/n_tty.c:1516 n_tty_lookahead_flow_ctrl+0x2cd/0x2f0 drivers/tty/n_tty.c:1516 tty_port_default_lookahead_buf+0x142/0x200 drivers/tty/tty_port.c:59 lookahead_bufs drivers/tty/tty_buffer.c:427 [inline] flush_to_ldisc+0x906/0xdc0 drivers/tty/tty_buffer.c:497 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2703 worker_thread+0xf45/0x1490 kernel/workqueue.c:2784 kthread+0x3ed/0x540 kernel/kthread.c:388 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc+0x121/0x3c0 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:179 [inline] __tty_buffer_request_room+0x36e/0x6c0 drivers/tty/tty_buffer.c:272 __tty_insert_flip_string_flags+0x140/0x560 drivers/tty/tty_buffer.c:308 tty_insert_flip_char include/linux/tty_flip.h:77 [inline] uart_insert_char+0x39e/0xa00 drivers/tty/serial/serial_core.c:3494 serial8250_read_char+0x1a2/0x5d0 drivers/tty/serial/8250/8250_port.c:1760 serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1777 [inline] serial8250_handle_irq+0x77b/0xb30 drivers/tty/serial/8250/8250_port.c:1937 serial8250_default_handle_irq+0x11a/0x2a0 drivers/tty/serial/8250/8250_port.c:1962 serial8250_interrupt+0xc0/0x350 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x113/0xc90 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xef/0x2c0 kernel/irq/handle.c:210 handle_edge_irq+0x341/0xf90 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x94/0x1f0 arch/x86/kernel/irq.c:257 common_interrupt+0x89/0xa0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:636 CPU: 0 PID: 1031 Comm: kworker/u4:7 Not tainted 6.7.0-rc2-syzkaller-00095-gd3fa86b1a7b4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Workqueue: events_unbound flush_to_ldisc ===================================================== --- 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 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
