syzbot

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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff888237d1b8e8 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x1ea/0x850 kernel/time/hrtimer.c:2105
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x30 kernel/locking/spinlock.c:198
 unix_stream_data_wait net/unix/af_unix.c:2746 [inline]
 unix_stream_read_generic+0xf88/0x1630 net/unix/af_unix.c:3004
 unix_stream_recvmsg+0xfc/0x130 net/unix/af_unix.c:3169
 sock_recvmsg_nosec net/socket.c:1137 [inline]
 sock_recvmsg+0xf5/0x120 net/socket.c:1159
 ____sys_recvmsg+0xf5/0x280 net/socket.c:2918
 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2960
 __sys_recvmsg net/socket.c:2993 [inline]
 __do_sys_recvmsg net/socket.c:2999 [inline]
 __se_sys_recvmsg net/socket.c:2996 [inline]
 __x64_sys_recvmsg+0xd1/0x160 net/socket.c:2996
 x64_sys_call+0x2b1a/0x3020 arch/x86/include/generated/asm/syscalls_64.h:48
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d1b8e8 of 8 bytes by task 12302 on cpu 0:
 print_cpu+0x2fb/0x670 kernel/time/timer_list.c:129
 timer_list_show+0x107/0x170 kernel/time/timer_list.c:291
 seq_read_iter+0x636/0x940 fs/seq_file.c:273
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x471/0x6c0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 splice_direct_to_actor+0x26e/0x670 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7fffffffffffffff -> 0x0000007270dd2cf2

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12302 Comm: syz.1.2656 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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