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BUG: KCSAN: data-race in do_sync_mmap_readahead / do_sync_mmap_readahead

write to 0xffff888104c08980 of 4 bytes by task 27519 on cpu 1:
 do_sync_mmap_readahead+0x32f/0x3b0 mm/filemap.c:3207
 filemap_fault+0x3d3/0xb70 mm/filemap.c:3302
 __do_fault mm/memory.c:4176 [inline]
 do_read_fault mm/memory.c:4530 [inline]
 do_fault mm/memory.c:4659 [inline]
 do_pte_missing mm/memory.c:3647 [inline]
 handle_pte_fault mm/memory.c:4947 [inline]
 __handle_mm_fault mm/memory.c:5089 [inline]
 handle_mm_fault+0x12f4/0x2c60 mm/memory.c:5243
 do_user_addr_fault arch/x86/mm/fault.c:1440 [inline]
 handle_page_fault arch/x86/mm/fault.c:1534 [inline]
 exc_page_fault+0x67e/0x780 arch/x86/mm/fault.c:1590
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 __get_user_4+0x11/0x20 arch/x86/lib/getuser.S:75
 rds_getsockopt+0x5c/0x420 net/rds/af_rds.c:493
 __sys_getsockopt+0x17b/0x1e0 net/socket.c:2318
 __do_sys_getsockopt net/socket.c:2333 [inline]
 __se_sys_getsockopt net/socket.c:2330 [inline]
 __x64_sys_getsockopt+0x66/0x80 net/socket.c:2330
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888104c08980 of 4 bytes by task 27520 on cpu 0:
 do_sync_mmap_readahead+0x32f/0x3b0 mm/filemap.c:3207
 filemap_fault+0x3d3/0xb70 mm/filemap.c:3302
 __do_fault mm/memory.c:4176 [inline]
 do_read_fault mm/memory.c:4530 [inline]
 do_fault mm/memory.c:4659 [inline]
 do_pte_missing mm/memory.c:3647 [inline]
 handle_pte_fault mm/memory.c:4947 [inline]
 __handle_mm_fault mm/memory.c:5089 [inline]
 handle_mm_fault+0x12f4/0x2c60 mm/memory.c:5243
 do_user_addr_fault arch/x86/mm/fault.c:1440 [inline]
 handle_page_fault arch/x86/mm/fault.c:1534 [inline]
 exc_page_fault+0x67e/0x780 arch/x86/mm/fault.c:1590
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 __get_user_4+0x11/0x20 arch/x86/lib/getuser.S:75
 rds_getsockopt+0x5c/0x420 net/rds/af_rds.c:493
 __sys_getsockopt+0x17b/0x1e0 net/socket.c:2318
 __do_sys_getsockopt net/socket.c:2333 [inline]
 __se_sys_getsockopt net/socket.c:2330 [inline]
 __x64_sys_getsockopt+0x66/0x80 net/socket.c:2330
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000020

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27520 Comm: syz-executor.4 Not tainted 6.4.0-syzkaller-01371-g04fc8904d5d1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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