syzbot

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BUG: KCSAN: data-race in ondemand_readahead / ondemand_readahead

read to 0xffff888114884484 of 4 bytes by task 1575 on cpu 1:
 ondemand_readahead+0x15d/0x6b0 mm/readahead.c:581
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:696
 page_cache_sync_readahead include/linux/pagemap.h:1306 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2529
 filemap_splice_read+0x360/0x920 mm/filemap.c:2894
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
 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 0xffff888114884484 of 4 bytes by task 1582 on cpu 0:
 ondemand_readahead+0x30b/0x6b0 mm/readahead.c:648
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:696
 page_cache_sync_readahead include/linux/pagemap.h:1306 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2529
 filemap_splice_read+0x360/0x920 mm/filemap.c:2894
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x00000004 -> 0x00000005

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1582 Comm: syz.3.8866 Tainted: G        W          6.10.0-rc6-syzkaller-00051-g1dfe225e9af5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
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