syzbot

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BUG: KCSAN: data-race in kimage_alloc_page / zap_other_threads

write to 0xffff8880928ed738 of 8 bytes by task 22939 on cpu 0:
 sigaddset include/linux/signal.h:66 [inline]
 zap_other_threads+0x116/0x1e0 kernel/signal.c:1361
 do_group_exit+0x146/0x180 kernel/exit.c:898
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:914
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:912
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:912
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880928ed738 of 8 bytes by task 22943 on cpu 1:
 sigismember include/linux/signal.h:84 [inline]
 __fatal_signal_pending include/linux/sched/signal.h:363 [inline]
 fatal_signal_pending include/linux/sched/signal.h:368 [inline]
 kimage_alloc_pages kernel/kexec_core.c:303 [inline]
 kimage_alloc_page+0x15d/0x7c0 kernel/kexec_core.c:725
 kimage_load_normal_segment kernel/kexec_core.c:808 [inline]
 kimage_load_segment+0x4d0/0x7f0 kernel/kexec_core.c:925
 do_kexec_load+0x386/0x480 kernel/kexec.c:155
 __do_sys_kexec_load kernel/kexec.c:261 [inline]
 __se_sys_kexec_load+0x148/0x180 kernel/kexec.c:236
 __x64_sys_kexec_load+0x51/0x60 kernel/kexec.c:236
 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: 22943 Comm: syz-executor.5 Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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