syzbot

PM: suspend entry (deep)
Filesystems sync: 0.011 seconds
Freezing user space processes ... 
==================================================================
BUG: KCSAN: data-race in exit_signals / freeze_task

write to 0xffff88812f10f0ac of 4 bytes by task 27080 on cpu 0:
 exit_signals+0xe1/0x4a0 kernel/signal.c:2927
 do_exit+0x194/0x1560 kernel/exit.c:782
 kthread+0x1d8/0x1f0 kernel/kthread.c:315
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88812f10f0ac of 4 bytes by task 27083 on cpu 1:
 freezing_slow_path kernel/freezer.c:39 [inline]
 freezing include/linux/freezer.h:39 [inline]
 freeze_task+0xcb/0x280 kernel/freezer.c:132
 try_to_freeze_tasks+0x138/0x5f0 kernel/power/process.c:53
 freeze_processes+0xbe/0x180 kernel/power/process.c:140
 suspend_freeze_processes kernel/power/power.h:253 [inline]
 suspend_prepare+0x9a/0x2c0 kernel/power/suspend.c:359
 enter_state+0x1fd/0x530 kernel/power/suspend.c:576
 pm_suspend+0x4b/0x130 kernel/power/suspend.c:613
 state_store+0x1f2/0x210 kernel/power/main.c:658
 kobj_attr_store+0x40/0x60 lib/kobject.c:856
 sysfs_kf_write+0xa6/0xc0 fs/sysfs/file.c:139
 kernfs_fop_write_iter+0x1d3/0x2d0 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1319 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00388040 -> 0x00388044

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27083 Comm: syz-executor.4 Tainted: G        W         5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
(elapsed 0.059 seconds) done.
OOM killer disabled.
Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
printk: Suspending console(s) (use no_console_suspend to debug)
ACPI: Preparing to enter system sleep state S3
PM: Saving platform NVS memory
Disabling non-boot CPUs ...
smpboot: CPU 1 is now offline
kvm-clock: cpu 0, msr 4506001, primary cpu clock, resume
ACPI: Low-level resume complete
PM: Restoring platform NVS memory
kvm-guest: stealtime: cpu 0, msr 237c170c0
Enabling non-boot CPUs ...
x86: Booting SMP configuration:
smpboot: Booting Node 0 Processor 1 APIC 0x1
CPU1 is up
ACPI: Waking up from system sleep state S3
OOM killer enabled.
Restarting tasks ... done.
PM: suspend exit