syzbot

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BUG: KCSAN: data-race in copy_mm / mmap_region

read-write to 0xffff8881042c3470 of 4 bytes by task 20460 on cpu 0:
 __mmap_new_vma mm/vma.c:2498 [inline]
 __mmap_region mm/vma.c:2669 [inline]
 mmap_region+0x112b/0x1630 mm/vma.c:2739
 do_mmap+0x9b3/0xbe0 mm/mmap.c:558
 vm_mmap_pgoff+0x17a/0x2e0 mm/util.c:580
 ksys_mmap_pgoff+0x268/0x310 mm/mmap.c:604
 x64_sys_call+0x14a3/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881042c33c0 of 1408 bytes by task 20462 on cpu 1:
 dup_mm kernel/fork.c:1479 [inline]
 copy_mm+0xe2/0x370 kernel/fork.c:1537
 copy_process+0xd08/0x2000 kernel/fork.c:2175
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2605
 __do_sys_clone kernel/fork.c:2748 [inline]
 __se_sys_clone kernel/fork.c:2732 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2732
 x64_sys_call+0x119c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 20462 Comm: syz.3.5645 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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lo speed is unknown, defaulting to 1000
lo speed is unknown, defaulting to 1000
lo speed is unknown, defaulting to 1000