[syzbot] KMSAN: uninit-value in n_tty_receive_buf_common (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8b936c96768e kmsan: core: remove the accidentally committe..
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=16469fc5b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e00a8959fdd3f3e8
dashboard link: https://syzkaller.appspot.com/bug?extid=b68d24ad0de64bdba684
compiler: clang version 14.0.0 (g...@github.com:llvm/llvm-project.git 0996585c8e3b3d409494eb5f1cad714b9e1f7fb5), GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=150a1e4db00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11c305bdb00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b68d24...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
BUG: KMSAN: uninit-value in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
BUG: KMSAN: uninit-value in n_tty_receive_buf_standard drivers/tty/n_tty.c:1557 [inline]
BUG: KMSAN: uninit-value in __receive_buf drivers/tty/n_tty.c:1577 [inline]
BUG: KMSAN: uninit-value in n_tty_receive_buf_common+0x1e6c/0x10360 drivers/tty/n_tty.c:1674
variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
n_tty_receive_buf_standard drivers/tty/n_tty.c:1557 [inline]
__receive_buf drivers/tty/n_tty.c:1577 [inline]
n_tty_receive_buf_common+0x1e6c/0x10360 drivers/tty/n_tty.c:1674
n_tty_receive_buf2+0xbe/0xd0 drivers/tty/n_tty.c:1709
tty_ldisc_receive_buf+0x15e/0x390 drivers/tty/tty_buffer.c:471
tty_port_default_receive_buf+0x14b/0x1e0 drivers/tty/tty_port.c:39
receive_buf drivers/tty/tty_buffer.c:491 [inline]
flush_to_ldisc+0x5bf/0xa10 drivers/tty/tty_buffer.c:543
process_one_work+0xdc2/0x1820 kernel/workqueue.c:2298
worker_thread+0x10f1/0x2290 kernel/workqueue.c:2445
kthread+0x721/0x850 kernel/kthread.c:327
ret_from_fork+0x1f/0x30

Uninit was created at:
slab_post_alloc_hook mm/slab.h:524 [inline]
slab_alloc_node mm/slub.c:3251 [inline]
slab_alloc mm/slub.c:3259 [inline]
__kmalloc+0xc3c/0x12d0 mm/slub.c:4437
kmalloc include/linux/slab.h:595 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x4d2/0x900 drivers/tty/tty_buffer.c:275
__tty_insert_flip_char+0xe5/0x3d0 drivers/tty/tty_buffer.c:392
tty_insert_flip_char include/linux/tty_flip.h:36 [inline]
uart_insert_char+0x495/0xb70 drivers/tty/serial/serial_core.c:3139
serial8250_read_char+0x280/0x820 drivers/tty/serial/8250/8250_port.c:1769
serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1784 [inline]
serial8250_handle_irq+0x540/0x980 drivers/tty/serial/8250/8250_port.c:1927
serial8250_default_handle_irq+0x18f/0x370 drivers/tty/serial/8250/8250_port.c:1949
serial8250_interrupt+0x111/0x3f0 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x188/0xc90 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:198 [inline]
handle_irq_event+0x188/0x420 kernel/irq/handle.c:215
handle_edge_irq+0x472/0x13e0 kernel/irq/chip.c:822
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:231 [inline]
__common_interrupt+0xf8/0x360 arch/x86/kernel/irq.c:250
common_interrupt+0xb1/0xd0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x1e/0x40

CPU: 0 PID: 1056 Comm: kworker/u4:5 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
=====================================================


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[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.