syzbot

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BUG: KMSAN: uninit-value in scan_ordinary drivers/net/ppp/ppp_async.c:751 [inline]
BUG: KMSAN: uninit-value in ppp_async_input drivers/net/ppp/ppp_async.c:851 [inline]
BUG: KMSAN: uninit-value in ppp_asynctty_receive+0x85c/0x2d70 drivers/net/ppp/ppp_async.c:342
 scan_ordinary drivers/net/ppp/ppp_async.c:751 [inline]
 ppp_async_input drivers/net/ppp/ppp_async.c:851 [inline]
 ppp_asynctty_receive+0x85c/0x2d70 drivers/net/ppp/ppp_async.c:342
 tty_ldisc_receive_buf+0x1f7/0x2c0 drivers/tty/tty_buffer.c:398
 tty_port_default_receive_buf+0xd7/0x1a0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:452 [inline]
 flush_to_ldisc+0x43e/0xe40 drivers/tty/tty_buffer.c:502
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb65/0x1e40 kernel/workqueue.c:3385
 worker_thread+0xee4/0x1590 kernel/workqueue.c:3466
 kthread+0x53f/0x600 kernel/kthread.c:436
 ret_from_fork+0x20f/0x8d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4576 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_noprof+0x482/0x1660 mm/slub.c:5307
 kmalloc_noprof include/linux/slab.h:954 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:187 [inline]
 __tty_buffer_request_room+0x3d4/0x7a0 drivers/tty/tty_buffer.c:280
 __tty_insert_flip_string_flags+0x157/0x6e0 drivers/tty/tty_buffer.c:316
 tty_insert_flip_char include/linux/tty_flip.h:77 [inline]
 uart_insert_char+0x368/0x930 drivers/tty/serial/serial_core.c:3431
 serial8250_read_char+0x1ba/0x670 drivers/tty/serial/8250/8250_port.c:1643
 serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1660 [inline]
 serial8250_handle_irq_locked+0x6d4/0xa40 drivers/tty/serial/8250/8250_port.c:1820
 serial8250_handle_irq+0x189/0x710 drivers/tty/serial/8250/8250_port.c:1841
 serial8250_default_handle_irq+0x116/0x350 drivers/tty/serial/8250/8250_port.c:1855
 serial8250_interrupt+0xcb/0x3f0 drivers/tty/serial/8250/8250_core.c:86
 __handle_irq_event_percpu+0x118/0xf30 kernel/irq/handle.c:209
 handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
 handle_irq_event+0xe0/0x2a0 kernel/irq/handle.c:263
 handle_edge_irq+0x2a9/0xaf0 kernel/irq/chip.c:856
 generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
 handle_irq arch/x86/kernel/irq.c:262 [inline]
 call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
 __common_interrupt+0x9d/0x180 arch/x86/kernel/irq.c:333
 common_interrupt+0x94/0xb0 arch/x86/kernel/irq.c:326
 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:688

CPU: 1 UID: 0 PID: 12193 Comm: kworker/u8:21 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: ttyS-serial_8250 flush_to_ldisc
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