syzbot

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BUG: KCSAN: data-race in copy_mm / dup_mmap

read-write to 0xffff88811a5645f8 of 4 bytes by task 11225 on cpu 1:
 do_raw_write_seqcount_begin include/linux/seqlock.h:431 [inline]
 mm_lock_seqcount_begin include/linux/mmap_lock.h:87 [inline]
 mmap_write_lock_killable include/linux/mmap_lock.h:376 [inline]
 dup_mmap+0xd8/0xf20 mm/mmap.c:1731
 dup_mm kernel/fork.c:1477 [inline]
 copy_mm+0x11a/0x370 kernel/fork.c:1529
 copy_process+0xcf1/0x1fe0 kernel/fork.c:2169
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2599
 __do_sys_clone kernel/fork.c:2742 [inline]
 __se_sys_clone kernel/fork.c:2726 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2726
 x64_sys_call+0x2c59/0x2fb0 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

read to 0xffff88811a564500 of 1408 bytes by task 11223 on cpu 0:
 dup_mm kernel/fork.c:1471 [inline]
 copy_mm+0xe2/0x370 kernel/fork.c:1529
 copy_process+0xcf1/0x1fe0 kernel/fork.c:2169
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2599
 __do_sys_clone kernel/fork.c:2742 [inline]
 __se_sys_clone kernel/fork.c:2726 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2726
 x64_sys_call+0x2c59/0x2fb0 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: 0 UID: 0 PID: 11223 Comm: syz.0.2412 Not tainted 6.16.0-rc1-syzkaller-00236-g8c6bc74c7f89 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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