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BUG: KCSAN: data-race in shmem_fallocate / shmem_fault

write to 0xffff888101fed448 of 8 bytes by task 5765 on cpu 0:
 shmem_fallocate+0x245/0x890 mm/shmem.c:3691
 vfs_fallocate+0x368/0x3b0 fs/open.c:338
 madvise_remove mm/madvise.c:1034 [inline]
 madvise_vma_behavior mm/madvise.c:1269 [inline]
 madvise_walk_vmas mm/madvise.c:1511 [inline]
 do_madvise+0x14cc/0x2a60 mm/madvise.c:1698
 __do_sys_madvise mm/madvise.c:1714 [inline]
 __se_sys_madvise mm/madvise.c:1712 [inline]
 __x64_sys_madvise+0x61/0x70 mm/madvise.c:1712
 x64_sys_call+0x23b8/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:29
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101fed448 of 8 bytes by task 5770 on cpu 1:
 shmem_fault+0x9a/0x270 mm/shmem.c:2739
 __do_fault+0xb6/0x200 mm/memory.c:4994
 do_read_fault mm/memory.c:5414 [inline]
 do_fault mm/memory.c:5548 [inline]
 do_pte_missing mm/memory.c:4059 [inline]
 handle_pte_fault mm/memory.c:5893 [inline]
 __handle_mm_fault mm/memory.c:6036 [inline]
 handle_mm_fault+0xead/0x2b30 mm/memory.c:6205
 faultin_page mm/gup.c:1196 [inline]
 __get_user_pages+0xf64/0x2350 mm/gup.c:1491
 populate_vma_page_range mm/gup.c:1929 [inline]
 __mm_populate+0x25d/0x3c0 mm/gup.c:2032
 mm_populate include/linux/mm.h:3377 [inline]
 vm_mmap_pgoff+0x224/0x2d0 mm/util.c:584
 ksys_mmap_pgoff+0xd0/0x340 mm/mmap.c:607
 x64_sys_call+0x1945/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffffc90000e5bca8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5770 Comm: syz.5.506 Not tainted 6.14.0-syzkaller-09584-g7d06015d936c #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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