Hello, syzbot found the following issue on: HEAD commit: 17712b7ea075 Merge tag 'io_uring-6.11-20240802' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10bc6e75980000 kernel config: https://syzkaller.appspot.com/x/.config?x=9d6059ad10dde6fd dashboard link: https://syzkaller.appspot.com/bug?extid=290abdcd4f509377a0eb compiler: Debian clang version 15.0.6, 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: https://storage.googleapis.com/syzbot-assets/8ab4fb08b298/disk-17712b7e.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/22441c38ffc1/vmlinux-17712b7e.xz kernel image: https://storage.googleapis.com/syzbot-assets/faf4575a6197/bzImage-17712b7e.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+290abdcd4f509377a0eb@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: uninit-value in n_tty_lookahead_flow_ctrl+0x2cd/0x300 drivers/tty/n_tty.c:1516 n_tty_lookahead_flow_ctrl+0x2cd/0x300 drivers/tty/n_tty.c:1516 tty_port_default_lookahead_buf+0x144/0x210 drivers/tty/tty_port.c:59 lookahead_bufs drivers/tty/tty_buffer.c:428 [inline] flush_to_ldisc+0x8ec/0xdb0 drivers/tty/tty_buffer.c:498 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312 worker_thread+0xea5/0x1520 kernel/workqueue.c:3390 kthread+0x3dd/0x540 kernel/kthread.c:389 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Uninit was created at: slab_post_alloc_hook mm/slub.c:3994 [inline] slab_alloc_node mm/slub.c:4037 [inline] __do_kmalloc_node mm/slub.c:4157 [inline] __kmalloc_noprof+0x661/0xf30 mm/slub.c:4170 kmalloc_noprof include/linux/slab.h:685 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline] __tty_buffer_request_room+0x36e/0x6d0 drivers/tty/tty_buffer.c:273 __tty_insert_flip_string_flags+0x140/0x570 drivers/tty/tty_buffer.c:309 tty_insert_flip_char include/linux/tty_flip.h:77 [inline] uart_insert_char+0x39e/0xa10 drivers/tty/serial/serial_core.c:3560 serial8250_read_char+0x1a7/0x5d0 drivers/tty/serial/8250/8250_port.c:1743 serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1760 [inline] serial8250_handle_irq+0x77a/0xb80 drivers/tty/serial/8250/8250_port.c:1924 serial8250_default_handle_irq+0x120/0x2b0 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xc5/0x360 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x118/0xca0 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+0x340/0xfb0 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0x97/0x1f0 arch/x86/kernel/irq.c:285 common_interrupt+0x8f/0xa0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:693 CPU: 0 UID: 0 PID: 3456 Comm: kworker/u8:20 Not tainted 6.11.0-rc1-syzkaller-00272-g17712b7ea075 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 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 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
