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BUG: KCSAN: data-race in do_nanosleep / prepare_signal

read to 0xffff8880b2c940a4 of 4 bytes by interrupt on cpu 1:
 sig_task_ignored kernel/signal.c:94 [inline]
 sig_ignored kernel/signal.c:119 [inline]
 prepare_signal+0x1f5/0x7a0 kernel/signal.c:956
 send_sigqueue+0xc1/0x4b0 kernel/signal.c:1859
 posix_timer_event kernel/time/posix-timers.c:328 [inline]
 posix_timer_fn+0x10d/0x230 kernel/time/posix-timers.c:354
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline]
 console_unlock+0x8fa/0xb80 kernel/printk/printk.c:2481
 vprintk_emit+0x38f/0x4e0 kernel/printk/printk.c:1996
 vprintk_default+0x31/0x50 kernel/printk/printk.c:2023
 vprintk_func+0x85/0x140 kernel/printk/printk_safe.c:386
 printk+0x69/0x91 kernel/printk/printk.c:2056
 __nla_validate_parse.cold+0x24/0x4f lib/nlattr.c:393
 __nla_parse+0x4c/0x70 lib/nlattr.c:478
 nla_parse_nested_deprecated include/net/netlink.h:1166 [inline]
 tbf_change+0x79/0xe50 net/sched/sch_tbf.c:306
 tbf_init+0x80/0xa1 net/sched/sch_tbf.c:429
 qdisc_create+0x322/0x990 net/sched/sch_api.c:1237
 tc_modify_qdisc+0x288/0x10c0 net/sched/sch_api.c:1652
 rtnetlink_rcv_msg+0x1d3/0x500 net/core/rtnetlink.c:5245
 netlink_rcv_skb+0xb0/0x260 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:5263
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x354/0x430 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x456/0x770 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880b2c940a4 of 4 bytes by task 13216 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_nanosleep+0x14d/0x320 kernel/time/hrtimer.c:1871
 hrtimer_nanosleep+0x191/0x320 kernel/time/hrtimer.c:1924
 __do_sys_nanosleep kernel/time/hrtimer.c:1958 [inline]
 __se_sys_nanosleep kernel/time/hrtimer.c:1945 [inline]
 __x64_sys_nanosleep+0x106/0x150 kernel/time/hrtimer.c:1945
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13216 Comm: syz-executor.0 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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