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BUG: KCSAN: data-race in shmem_fallocate / shmem_fault

write to 0xffff888118775fe8 of 8 bytes by task 10710 on cpu 1:
 shmem_fallocate+0x22e/0x860 mm/shmem.c:3668
 vfs_fallocate+0x368/0x3b0 fs/open.c:338
 madvise_remove mm/madvise.c:1025 [inline]
 madvise_vma_behavior mm/madvise.c:1260 [inline]
 madvise_walk_vmas mm/madvise.c:1502 [inline]
 do_madvise+0x14da/0x2ad0 mm/madvise.c:1689
 __do_sys_madvise mm/madvise.c:1705 [inline]
 __se_sys_madvise mm/madvise.c:1703 [inline]
 __x64_sys_madvise+0x61/0x70 mm/madvise.c:1703
 x64_sys_call+0x23ab/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:29
 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 0xffff888118775fe8 of 8 bytes by task 10728 on cpu 0:
 shmem_fault+0x97/0x250 mm/shmem.c:2716
 __do_fault+0xb6/0x200 mm/memory.c:4977
 do_read_fault mm/memory.c:5392 [inline]
 do_fault mm/memory.c:5526 [inline]
 do_pte_missing mm/memory.c:4047 [inline]
 handle_pte_fault mm/memory.c:5889 [inline]
 __handle_mm_fault mm/memory.c:6032 [inline]
 handle_mm_fault+0xe98/0x2ac0 mm/memory.c:6201
 faultin_page mm/gup.c:1196 [inline]
 __get_user_pages+0xf6a/0x2350 mm/gup.c:1491
 __get_user_pages_locked mm/gup.c:1757 [inline]
 get_dump_page+0xb8/0x1b0 mm/gup.c:2275
 dump_user_range+0xc6/0x550 fs/coredump.c:943
 elf_core_dump+0x1d17/0x1ea0 fs/binfmt_elf.c:2129
 do_coredump+0x17fe/0x1f40 fs/coredump.c:758
 get_signal+0xd4f/0x1000 kernel/signal.c:3021
 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]
 irqentry_exit_to_user_mode+0xa7/0x120 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x0000000000000000 -> 0xffffc90003b47ca8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 10728 Comm: syz.8.17723 Not tainted 6.14.0-rc2-syzkaller-00185-g128c8f96eb86 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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