syzbot

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BUG: KCSAN: data-race in serial8250_do_startup / serial8250_handle_irq

write to 0xffffffff88c1a7a6 of 1 bytes by task 25644 on cpu 1:
 serial8250_do_startup+0x165c/0x1ea0 drivers/tty/serial/8250/8250_port.c:2456
 serial8250_startup+0x40/0x50 drivers/tty/serial/8250/8250_port.c:2478
 uart_port_startup drivers/tty/serial/serial_core.c:323 [inline]
 uart_startup+0x481/0x9b0 drivers/tty/serial/serial_core.c:367
 uart_port_activate+0x66/0xb0 drivers/tty/serial/serial_core.c:2010
 tty_port_open+0x160/0x1f0 drivers/tty/tty_port.c:784
 uart_open+0x30/0x40 drivers/tty/serial/serial_core.c:1990
 tty_open+0x3d4/0xb00 drivers/tty/tty_io.c:2146
 chrdev_open+0x2f9/0x370 fs/char_dev.c:414
 do_dentry_open+0x621/0xa20 fs/open.c:945
 vfs_open+0x38/0x1f0 fs/open.c:1075
 do_open fs/namei.c:3828 [inline]
 path_openat+0x1ac2/0x1fa0 fs/namei.c:3987
 do_filp_open+0x107/0x230 fs/namei.c:4014
 do_sys_openat2+0xab/0x120 fs/open.c:1402
 do_sys_open fs/open.c:1417 [inline]
 __do_sys_openat fs/open.c:1433 [inline]
 __se_sys_openat fs/open.c:1428 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1428
 x64_sys_call+0x2b30/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88c1a7a6 of 1 bytes by interrupt on cpu 0:
 serial8250_handle_irq+0x3c8/0x620 drivers/tty/serial/8250/8250_port.c:1947
 serial8250_default_handle_irq+0x94/0x130 drivers/tty/serial/8250/8250_port.c:1969
 serial8250_interrupt+0x5d/0x120 drivers/tty/serial/8250/8250_core.c:86
 __handle_irq_event_percpu+0x95/0x490 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:210
 handle_edge_irq+0x16d/0x5b0 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+0x58/0xe0 arch/x86/kernel/irq.c:285
 common_interrupt+0x7c/0x90 arch/x86/kernel/irq.c:278
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 __tlb_remove_folio_pages_size mm/mmu_gather.c:179 [inline]
 __tlb_remove_folio_pages+0x30/0x210 mm/mmu_gather.c:208
 zap_present_folio_ptes mm/memory.c:1531 [inline]
 zap_present_ptes mm/memory.c:1585 [inline]
 zap_pte_range mm/memory.c:1627 [inline]
 zap_pmd_range mm/memory.c:1753 [inline]
 zap_pud_range mm/memory.c:1782 [inline]
 zap_p4d_range mm/memory.c:1803 [inline]
 unmap_page_range+0x1185/0x2380 mm/memory.c:1824
 unmap_single_vma+0x142/0x1d0 mm/memory.c:1870
 unmap_vmas+0x18d/0x2b0 mm/memory.c:1914
 exit_mmap+0x18a/0x680 mm/mmap.c:1668
 __mmput+0x28/0x1d0 kernel/fork.c:1353
 mmput+0x4c/0x60 kernel/fork.c:1375
 exit_mm+0xe4/0x190 kernel/exit.c:570
 do_exit+0x55e/0x17f0 kernel/exit.c:925
 do_group_exit+0x102/0x150 kernel/exit.c:1087
 get_signal+0xeb9/0x1000 kernel/signal.c:3017
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x62/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x05

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 25637 Comm: syz.4.18156 Not tainted 6.13.0-rc3-syzkaller-00082-gbaaa2567a712 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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