syzbot

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BUG: KCSAN: data-race in hrtimer_start_range_ns / print_cpu

write to 0xffff888237c1b8e8 of 8 bytes by task 3741 on cpu 0:
 __hrtimer_reprogram kernel/time/hrtimer.c:713 [inline]
 hrtimer_reprogram kernel/time/hrtimer.c:899 [inline]
 hrtimer_start_range_ns+0xc6d/0x10a0 kernel/time/hrtimer.c:1492
 hrtimer_start_expires include/linux/hrtimer.h:234 [inline]
 hrtimer_restart include/linux/hrtimer.h:242 [inline]
 common_hrtimer_rearm+0x85/0x90 kernel/time/posix-timers.c:296
 __posixtimer_deliver_signal kernel/time/posix-timers.c:314 [inline]
 posixtimer_deliver_signal+0x11f/0x300 kernel/time/posix-timers.c:340
 dequeue_signal+0x2ce/0x3a0 kernel/signal.c:660
 get_signal+0x375/0xf20 kernel/signal.c:2917
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x6f/0x820 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c1b8e8 of 8 bytes by task 3728 on cpu 1:
 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: 0x0000000b279447ee -> 0x0000000b27940d7a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3728 Comm: syz.3.66 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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