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BUG: KCSAN: data-race in copy_mm / rwsem_down_write_slowpath

write to 0xffff8881045adce8 of 8 bytes by task 3621 on cpu 1:
 __rwsem_del_waiter kernel/locking/rwsem.c:372 [inline]
 rwsem_try_write_lock kernel/locking/rwsem.c:685 [inline]
 rwsem_down_write_slowpath+0x661/0xab0 kernel/locking/rwsem.c:1189
 __down_write_common kernel/locking/rwsem.c:1347 [inline]
 __down_write_killable kernel/locking/rwsem.c:1361 [inline]
 down_write_killable+0xaf/0xd0 kernel/locking/rwsem.c:1646
 mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 vm_mmap_pgoff+0xec/0x2d0 mm/util.c:579
 ksys_mmap_pgoff+0xc1/0x310 mm/mmap.c:619
 x64_sys_call+0x23b3/0x2550 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881045adb00 of 1728 bytes by task 3615 on cpu 0:
 dup_mm kernel/fork.c:1537 [inline]
 copy_mm+0xd6/0x340 kernel/fork.c:1595
 copy_process+0x10ad/0x2340 kernel/fork.c:2307
 kernel_clone+0x1c0/0x5f0 kernel/fork.c:2766
 __do_sys_clone kernel/fork.c:2908 [inline]
 __se_sys_clone kernel/fork.c:2892 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2892
 x64_sys_call+0x2479/0x2550 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3615 Comm: syz.3.22 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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