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BUG: KCSAN: data-race in read_pages / read_pages

write to 0xffff8881072dde84 of 4 bytes by task 6696 on cpu 1:
 read_pages+0x284/0x530 mm/readahead.c:172
 page_cache_ra_unbounded+0x2aa/0x2e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:546 [inline]
 ondemand_readahead+0x524/0x690 mm/readahead.c:668
 page_cache_sync_ra+0x27e/0x2a0 mm/readahead.c:695
 page_cache_sync_readahead include/linux/pagemap.h:1293 [inline]
 filemap_get_pages+0x251/0xe90 mm/filemap.c:2556
 filemap_read+0x214/0x680 mm/filemap.c:2652
 generic_file_read_iter+0x78/0x330 mm/filemap.c:2831
 ext4_file_read_iter+0x1d8/0x2a0
 call_read_iter include/linux/fs.h:1950 [inline]
 copy_splice_read+0x26b/0x4b0 fs/splice.c:364
 vfs_splice_read fs/splice.c:992 [inline]
 splice_direct_to_actor+0x2aa/0x690 fs/splice.c:1069
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 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

read to 0xffff8881072dde84 of 4 bytes by task 6688 on cpu 0:
 read_pages+0x259/0x530 mm/readahead.c:171
 page_cache_ra_unbounded+0x2aa/0x2e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:546 [inline]
 ondemand_readahead+0x524/0x690 mm/readahead.c:668
 page_cache_async_ra+0x94/0xa0 mm/readahead.c:717
 filemap_readahead mm/filemap.c:2531 [inline]
 filemap_get_pages+0x386/0xe90 mm/filemap.c:2572
 filemap_read+0x214/0x680 mm/filemap.c:2652
 generic_file_read_iter+0x78/0x330 mm/filemap.c:2831
 ext4_file_read_iter+0x1d8/0x2a0
 call_read_iter include/linux/fs.h:1950 [inline]
 copy_splice_read+0x26b/0x4b0 fs/splice.c:364
 vfs_splice_read fs/splice.c:992 [inline]
 splice_direct_to_actor+0x2aa/0x690 fs/splice.c:1069
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 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: 0x0000000f -> 0x00000009

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6688 Comm: syz-executor.2 Not tainted 6.6.0-rc6-syzkaller-00039-g06dc10eae55b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
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