KCSAN: data-race in page_cache_sync_ra / page_cache_sync

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in page_cache_sync_ra / page_cache_sync_ra fs mm				3	210d	238d	0/28	auto-obsoleted due to no activity on 2024/10/09 07:18

loop0: detected capacity change from 0 to 2048
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BUG: KCSAN: data-race in page_cache_sync_ra / page_cache_sync_ra

write to 0xffff888104492c9c of 4 bytes by task 7938 on cpu 1:
 page_cache_sync_ra+0x540/0x680 mm/readahead.c:-1
 filemap_get_pages+0x2ba/0x11b0 mm/filemap.c:2602
 filemap_splice_read+0x35a/0x930 mm/filemap.c:2992
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xd9/0x150 fs/splice.c:1227
 do_sendfile+0x40a/0x690 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
 x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104492c9c of 4 bytes by task 7932 on cpu 0:
 page_cache_ra_order mm/readahead.c:533 [inline]
 page_cache_sync_ra+0x59c/0x680 mm/readahead.c:621
 filemap_get_pages+0x2ba/0x11b0 mm/filemap.c:2602
 filemap_splice_read+0x35a/0x930 mm/filemap.c:2992
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xd9/0x150 fs/splice.c:1227
 do_sendfile+0x40a/0x690 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
 x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000f -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7932 Comm: syz.0.1155 Not tainted 6.14.0-syzkaller-09584-g7d06015d936c #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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