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BUG: KCSAN: data-race in ondemand_readahead / ondemand_readahead

read to 0xffff88811092c384 of 4 bytes by task 27565 on cpu 0:
 ondemand_readahead+0x15d/0x6b0 mm/readahead.c:581
 page_cache_async_ra+0x94/0xa0 mm/readahead.c:718
 filemap_readahead mm/filemap.c:2504 [inline]
 filemap_get_pages+0x398/0xfb0 mm/filemap.c:2545
 filemap_read+0x21c/0x690 mm/filemap.c:2625
 generic_file_read_iter+0x78/0x340 mm/filemap.c:2806
 ext4_file_read_iter+0x1d8/0x2a0
 do_iter_readv_writev+0x339/0x3e0
 vfs_readv+0x1e5/0x660 fs/read_write.c:932
 do_preadv fs/read_write.c:1049 [inline]
 __do_sys_preadv fs/read_write.c:1099 [inline]
 __se_sys_preadv fs/read_write.c:1094 [inline]
 __x64_sys_preadv+0x100/0x1c0 fs/read_write.c:1094
 x64_sys_call+0x1d82/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:296
 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

write to 0xffff88811092c384 of 4 bytes by task 27568 on cpu 1:
 ondemand_readahead+0x354/0x6b0
 page_cache_async_ra+0x94/0xa0 mm/readahead.c:718
 do_async_mmap_readahead mm/filemap.c:3203 [inline]
 filemap_fault+0x2d3/0xa60 mm/filemap.c:3299
 __do_fault+0xb6/0x200 mm/memory.c:4562
 do_read_fault mm/memory.c:4926 [inline]
 do_fault mm/memory.c:5056 [inline]
 do_pte_missing mm/memory.c:3903 [inline]
 handle_pte_fault mm/memory.c:5380 [inline]
 __handle_mm_fault mm/memory.c:5523 [inline]
 handle_mm_fault+0xdeb/0x2a80 mm/memory.c:5688
 faultin_page mm/gup.c:1290 [inline]
 __get_user_pages+0x49d/0xf10 mm/gup.c:1589
 populate_vma_page_range mm/gup.c:2029 [inline]
 __mm_populate+0x25b/0x3b0 mm/gup.c:2132
 mm_populate include/linux/mm.h:3464 [inline]
 __do_sys_mlockall mm/mlock.c:777 [inline]
 __se_sys_mlockall+0x2c5/0x370 mm/mlock.c:753
 __x64_sys_mlockall+0x1f/0x30 mm/mlock.c:753
 x64_sys_call+0x2a79/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:152
 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

value changed: 0x00000020 -> 0x00000040

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27568 Comm: syz-executor.0 Tainted: G        W          6.10.0-rc2-syzkaller-00010-g2ab795141095 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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