syzbot

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BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff888237c1b8e8 of 8 bytes by interrupt on cpu 0:
 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
 is_atomic kernel/kcsan/core.c:249 [inline]
 should_watch kernel/kcsan/core.c:277 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_unaligned_write8+0x11d/0x180 kernel/kcsan/core.c:1025
 __memcg_slab_post_alloc_hook+0x34f/0x7d0 mm/memcontrol.c:3510
 memcg_slab_post_alloc_hook mm/slub.c:2461 [inline]
 slab_post_alloc_hook mm/slub.c:4580 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_lru_noprof+0x1eb/0x400 mm/slub.c:4917
 __d_alloc+0x37/0x340 fs/dcache.c:1807
 d_alloc_pseudo+0x1e/0x80 fs/dcache.c:1938
 alloc_path_pseudo fs/file_table.c:405 [inline]
 alloc_file_pseudo+0x91/0x190 fs/file_table.c:421
 sock_alloc_file+0x9c/0x1e0 net/socket.c:543
 __sys_socketpair+0x2b7/0x420 net/socket.c:1900
 __do_sys_socketpair net/socket.c:1922 [inline]
 __se_sys_socketpair net/socket.c:1919 [inline]
 __x64_sys_socketpair+0x52/0x60 net/socket.c:1919
 x64_sys_call+0x2de5/0x3020 arch/x86/include/generated/asm/syscalls_64.h:54
 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 0xffff888237c1b8e8 of 8 bytes by task 26911 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: 0x0000011970807a37 -> 0x7fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 26911 Comm: syz.8.6667 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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