syzbot

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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff88813bd1dea0 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x1ec/0xa30 kernel/time/hrtimer.c:1637
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x200 arch/x86/kernel/apic/apic.c:1106
 asm_call_irq_on_stack+0xf/0x20
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0x52/0x90 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:629
 is_atomic kernel/kcsan/core.c:234 [inline]
 should_watch kernel/kcsan/core.c:262 [inline]
 check_access kernel/kcsan/core.c:631 [inline]
 __tsan_read1+0x116/0x180 kernel/kcsan/core.c:839
 strlen+0x1b/0x40 lib/string.c:565
 __sprint_symbol+0x98/0x170 kernel/kallsyms.c:370
 sprint_symbol_no_offset+0x1d/0x30 kernel/kallsyms.c:412
 symbol_string+0x8a/0x190 lib/vsprintf.c:974
 pointer+0x21b/0x7e0 lib/vsprintf.c:2224
 vsnprintf+0x8a1/0xed0 lib/vsprintf.c:2623
 seq_vprintf+0x71/0xd0 fs/seq_file.c:395
 SEQ_printf+0x76/0xb0 kernel/time/timer_list.c:38
 print_timer kernel/time/timer_list.c:49 [inline]
 print_active_timers kernel/time/timer_list.c:91 [inline]
 print_base kernel/time/timer_list.c:112 [inline]
 print_cpu+0x28e/0x690 kernel/time/timer_list.c:123
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:283
 seq_read_iter+0x60b/0x910 fs/seq_file.c:269
 proc_reg_read_iter+0xfc/0x170 fs/proc/inode.c:310
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88813bd1dea0 of 8 bytes by task 11654 on cpu 0:
 print_cpu+0x32e/0x690 kernel/time/timer_list.c:133
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:283
 seq_read_iter+0x60b/0x910 fs/seq_file.c:269
 proc_reg_read_iter+0xfc/0x170 fs/proc/inode.c:310
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11654 Comm: syz-executor.4 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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