syzbot

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BUG: KMSAN: uninit-value in ppp_async_input drivers/net/ppp/ppp_async.c:848 [inline]
BUG: KMSAN: uninit-value in ppp_asynctty_receive+0xcd3/0x2da0 drivers/net/ppp/ppp_async.c:342
 ppp_async_input drivers/net/ppp/ppp_async.c:848 [inline]
 ppp_asynctty_receive+0xcd3/0x2da0 drivers/net/ppp/ppp_async.c:342
 tty_ldisc_receive_buf+0x1f4/0x2c0 drivers/tty/tty_buffer.c:391
 tty_port_default_receive_buf+0xd7/0x1a0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x44c/0xdb0 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4167 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 __do_kmalloc_node mm/slub.c:4340 [inline]
 __kmalloc_noprof+0x95f/0x1310 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:909 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline]
 __tty_buffer_request_room+0x3d4/0x7a0 drivers/tty/tty_buffer.c:273
 __tty_insert_flip_string_flags+0x157/0x6f0 drivers/tty/tty_buffer.c:309
 tty_insert_flip_char include/linux/tty_flip.h:77 [inline]
 uart_insert_char+0x368/0x930 drivers/tty/serial/serial_core.c:3515
 serial8250_read_char+0x1ba/0x670 drivers/tty/serial/8250/8250_port.c:1764
 serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1781 [inline]
 serial8250_handle_irq+0x930/0x1110 drivers/tty/serial/8250/8250_port.c:1945
 serial8250_default_handle_irq+0x116/0x2b0 drivers/tty/serial/8250/8250_port.c:1970
 serial8250_interrupt+0xc8/0x400 drivers/tty/serial/8250/8250_core.c:86
 __handle_irq_event_percpu+0x11c/0xbf0 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0xe0/0x2a0 kernel/irq/handle.c:210
 handle_edge_irq+0x450/0xfd0 kernel/irq/chip.c:831
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:254 [inline]
 call_irq_handler arch/x86/kernel/irq.c:266 [inline]
 __common_interrupt+0x9f/0x220 arch/x86/kernel/irq.c:292
 common_interrupt+0x94/0xb0 arch/x86/kernel/irq.c:285
 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:693

CPU: 1 UID: 0 PID: 3809 Comm: kworker/u8:13 Tainted: G        W           6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: events_unbound flush_to_ldisc
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