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BUG: KCSAN: data-race in vm_area_dup / vma_interval_tree_remove

read to 0xffff8881243de960 of 200 bytes by task 8246 on cpu 1:
 vm_area_dup+0x70/0xf0 kernel/fork.c:359
 dup_mmap kernel/fork.c:541 [inline]
 dup_mm+0x330/0xba0 kernel/fork.c:1361
 copy_mm kernel/fork.c:1417 [inline]
 copy_process+0x36f3/0x3b50 kernel/fork.c:2012
 _do_fork+0xfe/0x6e0 kernel/fork.c:2366
 __do_sys_clone kernel/fork.c:2521 [inline]
 __se_sys_clone kernel/fork.c:2502 [inline]
 __x64_sys_clone+0x12b/0x160 kernel/fork.c:2502
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881243de9b8 of 8 bytes by task 8182 on cpu 0:
 rb_set_parent include/linux/rbtree_augmented.h:159 [inline]
 __rb_erase_augmented include/linux/rbtree_augmented.h:279 [inline]
 rb_erase_augmented include/linux/rbtree_augmented.h:305 [inline]
 rb_erase_augmented_cached include/linux/rbtree_augmented.h:316 [inline]
 vma_interval_tree_remove+0x316/0x8a0 mm/interval_tree.c:23
 __remove_shared_vm_struct+0xad/0xd0 mm/mmap.c:154
 unlink_file_vma+0x69/0x90 mm/mmap.c:169
 free_pgtables+0xbe/0x200 mm/memory.c:382
 exit_mmap+0x151/0x300 mm/mmap.c:3162
 __mmput kernel/fork.c:1079 [inline]
 mmput+0xea/0x280 kernel/fork.c:1100
 exec_mmap fs/exec.c:1048 [inline]
 flush_old_exec+0x655/0xfd0 fs/exec.c:1281
 load_elf_binary+0x69a/0x2ec0 fs/binfmt_elf.c:847
 search_binary_handler fs/exec.c:1659 [inline]
 search_binary_handler+0x127/0x420 fs/exec.c:1636
 exec_binprm fs/exec.c:1702 [inline]
 __do_execve_file.isra.0+0xb76/0x11d0 fs/exec.c:1822
 do_execveat_common fs/exec.c:1868 [inline]
 do_execve fs/exec.c:1885 [inline]
 __do_sys_execve fs/exec.c:1961 [inline]
 __se_sys_execve fs/exec.c:1956 [inline]
 __x64_sys_execve+0x62/0x80 fs/exec.c:1956
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8182 Comm: net.agent Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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