KCSAN: data-race in filemap_read / filemap

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in filemap_read / filemap_read (6) prio:low fs	6	584	82d	439d	0/29	auto-obsoleted due to no activity on 2026/07/26 07:52
upstream	KCSAN: data-race in filemap_read / filemap_read fs	6	832	1010d	1849d	0/29	auto-obsoleted due to no activity on 2023/12/20 06:43
upstream	KCSAN: data-race in filemap_read / filemap_read (2) fs	6	2	979d	982d	0/29	auto-obsoleted due to no activity on 2024/01/26 23:06
upstream	KCSAN: data-race in filemap_read / filemap_read (3) fs	6	4	886d	921d	0/29	auto-obsoleted due to no activity on 2024/04/29 01:22
upstream	KCSAN: data-race in filemap_read / filemap_read (4) fs	6	1	787d	787d	0/29	auto-obsoleted due to no activity on 2024/08/06 15:23

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BUG: KCSAN: data-race in filemap_read / filemap_read

read to 0xffff8881034b75e8 of 8 bytes by task 16625 on cpu 1:
 filemap_read+0x85/0x8d0 mm/filemap.c:2675
 generic_file_read_iter+0x78/0x330 mm/filemap.c:2893
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x390/0x5d0 fs/splice.c:363
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x28e/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

write to 0xffff8881034b75e8 of 8 bytes by task 16630 on cpu 0:
 filemap_read+0x842/0x8d0 mm/filemap.c:2774
 generic_file_read_iter+0x78/0x330 mm/filemap.c:2893
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x390/0x5d0 fs/splice.c:363
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x28e/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: 0x0000000000000323 -> 0x0000000000000324

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16630 Comm: syz.5.4778 Not tainted 6.14.0-syzkaller-03576-g1e1ba8d23dae #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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