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BUG: KCSAN: data-race in ondemand_readahead / ondemand_readahead

write to 0xffff888145ce4978 of 8 bytes by task 16064 on cpu 1:
 ondemand_readahead+0x566/0x690 mm/readahead.c:606
 page_cache_async_ra+0x94/0xa0 mm/readahead.c:717
 do_async_mmap_readahead mm/filemap.c:3178 [inline]
 filemap_fault+0x3da/0xc30 mm/filemap.c:3232
 __do_fault mm/memory.c:4266 [inline]
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4763 [inline]
 do_pte_missing mm/memory.c:3731 [inline]
 handle_pte_fault mm/memory.c:5039 [inline]
 __handle_mm_fault mm/memory.c:5180 [inline]
 handle_mm_fault+0x13bd/0x2dd0 mm/memory.c:5345
 do_user_addr_fault arch/x86/mm/fault.c:1415 [inline]
 handle_page_fault arch/x86/mm/fault.c:1507 [inline]
 exc_page_fault+0x2f7/0x6d0 arch/x86/mm/fault.c:1563
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 fault_in_readable+0xf8/0x1b0
 fault_in_iov_iter_readable+0x152/0x190 lib/iov_iter.c:94
 generic_perform_write+0x106/0x410 mm/filemap.c:3917
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x297/0xe10
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x48a/0x790 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888145ce4978 of 8 bytes by task 16061 on cpu 0:
 ondemand_readahead+0x13a/0x690 mm/readahead.c:580
 page_cache_async_ra+0x94/0xa0 mm/readahead.c:717
 do_async_mmap_readahead mm/filemap.c:3178 [inline]
 filemap_fault+0x3da/0xc30 mm/filemap.c:3232
 __do_fault mm/memory.c:4266 [inline]
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4763 [inline]
 do_pte_missing mm/memory.c:3731 [inline]
 handle_pte_fault mm/memory.c:5039 [inline]
 __handle_mm_fault mm/memory.c:5180 [inline]
 handle_mm_fault+0x13bd/0x2dd0 mm/memory.c:5345
 do_user_addr_fault arch/x86/mm/fault.c:1415 [inline]
 handle_page_fault arch/x86/mm/fault.c:1507 [inline]
 exc_page_fault+0x2f7/0x6d0 arch/x86/mm/fault.c:1563
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 rep_movs_alternative+0x30/0x70 arch/x86/lib/copy_user_64.S:50
 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:127 [inline]
 _copy_from_user+0x80/0xd0 lib/usercopy.c:23
 copy_from_user include/linux/uaccess.h:183 [inline]
 copy_msghdr_from_user+0x54/0x2a0 net/socket.c:2516
 recvmsg_copy_msghdr net/socket.c:2771 [inline]
 ___sys_recvmsg net/socket.c:2843 [inline]
 do_recvmmsg+0x290/0x720 net/socket.c:2941
 __sys_recvmmsg net/socket.c:3020 [inline]
 __do_sys_recvmmsg net/socket.c:3043 [inline]
 __se_sys_recvmmsg net/socket.c:3036 [inline]
 __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:3036
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000059 -> 0x000000000000005a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16061 Comm: syz-executor.1 Not tainted 6.7.0-rc8-syzkaller-00174-g95c8a35f1c01 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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