syzbot

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BUG: KCSAN: data-race in do_nanosleep / get_task_mm

write to 0xffff8880b4909024 of 4 bytes by task 10797 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_nanosleep+0x121/0x3a0 kernel/time/hrtimer.c:1883
 hrtimer_nanosleep kernel/time/hrtimer.c:1936 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1970 [inline]
 __se_sys_nanosleep+0x20b/0x2a0 kernel/time/hrtimer.c:1957
 __x64_sys_nanosleep+0x2d/0x40 kernel/time/hrtimer.c:1957
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b4909024 of 4 bytes by task 10803 on cpu 1:
 get_task_mm+0x3e/0x90 kernel/fork.c:1209
 proc_pid_status+0x35/0x1350 fs/proc/array.c:408
 proc_single_show+0x84/0x100 fs/proc/base.c:775
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 do_loop_readv_writev fs/read_write.c:742 [inline]
 do_iter_read+0x3d2/0x4b0 fs/read_write.c:784
 vfs_readv fs/read_write.c:902 [inline]
 do_preadv+0x13b/0x230 fs/read_write.c:994
 __do_sys_preadv fs/read_write.c:1044 [inline]
 __se_sys_preadv fs/read_write.c:1039 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1039
 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: 1 PID: 10803 Comm: syz-executor.2 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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