==================================================================
BUG: KCSAN: data-race in ondemand_readahead / read_pages

read-write to 0xffff88811529f880 of 4 bytes by task 18266 on cpu 0:
 read_pages+0x23f/0x540 mm/readahead.c:170
 page_cache_ra_unbounded+0x225/0x2e0
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:539 [inline]
 ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
 page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
 filemap_splice_read+0x360/0x920 mm/filemap.c:2870
 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+0x3b9/0x970 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+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88811529f880 of 4 bytes by task 18271 on cpu 1:
 ondemand_readahead+0x2e2/0x6c0 mm/readahead.c:639
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
 page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
 filemap_splice_read+0x360/0x920 mm/filemap.c:2870
 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+0x3b9/0x970 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+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000d -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18271 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00355-g2c8159388952 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================
==================================================================
BUG: KCSAN: data-race in read_pages / read_pages

read-write to 0xffff88811529f880 of 4 bytes by task 18266 on cpu 1:
 read_pages+0x23f/0x540 mm/readahead.c:170
 page_cache_ra_unbounded+0x225/0x2e0
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:539 [inline]
 ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
 page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
 filemap_splice_read+0x360/0x920 mm/filemap.c:2870
 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+0x3b9/0x970 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+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read-write to 0xffff88811529f880 of 4 bytes by task 18271 on cpu 0:
 read_pages+0x23f/0x540 mm/readahead.c:170
 page_cache_ra_unbounded+0x2a4/0x2e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:539 [inline]
 ondemand_readahead+0x549/0x6c0 mm/readahead.c:661
 page_cache_sync_ra+0xe0/0xf0 mm/readahead.c:688
 page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
 filemap_get_pages+0x252/0xfb0 mm/filemap.c:2505
 filemap_splice_read+0x360/0x920 mm/filemap.c:2870
 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+0x3b9/0x970 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+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000a -> 0xffffffef

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18271 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00355-g2c8159388952 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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