syzbot

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BUG: KCSAN: data-race in __filemap_add_folio / file_write_and_wait_range

read-write to 0xffff888107916778 of 8 bytes by task 11449 on cpu 1:
 __filemap_add_folio+0x439/0x710 mm/filemap.c:918
 filemap_add_folio+0x9c/0x1b0 mm/filemap.c:970
 page_cache_ra_unbounded+0x148/0x2e0 mm/readahead.c:252
 do_page_cache_ra mm/readahead.c:303 [inline]
 page_cache_ra_order mm/readahead.c:547 [inline]
 ondemand_readahead+0x542/0x6b0 mm/readahead.c:669
 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_splice_read+0x360/0x920 mm/filemap.c:2894
 ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
 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/0x960 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

read to 0xffff888107916778 of 8 bytes by task 11444 on cpu 0:
 mapping_needs_writeback mm/filemap.c:635 [inline]
 file_write_and_wait_range+0x6d/0x170 mm/filemap.c:787
 ext4_sync_file+0x134/0x6c0 fs/ext4/fsync.c:158
 vfs_fsync_range+0x122/0x140 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2794 [inline]
 ext4_buffered_write_iter+0x338/0x380 fs/ext4/file.c:305
 ext4_file_write_iter+0x29f/0xe30
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x960 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: 0x0000000000000038 -> 0x0000000000000040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11444 Comm: syz-executor.2 Not tainted 6.10.0-rc3-syzkaller-00249-gb5beaa44747b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
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