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BUG: KCSAN: data-race in __rb_insert_augmented / vm_area_dup

write to 0xffff8881229b4120 of 8 bytes by task 19342 on cpu 0:
 rb_set_parent_color include/linux/rbtree_augmented.h:165 [inline]
 __rb_insert lib/rbtree.c:187 [inline]
 __rb_insert_augmented+0x1e1/0x370 lib/rbtree.c:459
 rb_insert_augmented include/linux/rbtree_augmented.h:50 [inline]
 rb_insert_augmented_cached include/linux/rbtree_augmented.h:60 [inline]
 vma_interval_tree_insert+0x196/0x230 mm/interval_tree.c:23
 __vma_link_file+0xd9/0x110 mm/mmap.c:628
 vma_link+0xab/0x130 mm/mmap.c:654
 mmap_region+0x85e/0xd50 mm/mmap.c:1797
 do_mmap+0x6c8/0xba0 mm/mmap.c:1545
 do_mmap_pgoff include/linux/mm.h:2334 [inline]
 vm_mmap_pgoff+0x12d/0x190 mm/util.c:506
 ksys_mmap_pgoff+0x2d8/0x420 mm/mmap.c:1597
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:99 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:90 [inline]
 __x64_sys_mmap+0x2e/0x40 arch/x86/kernel/sys_x86_64.c:90
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881229b40c8 of 200 bytes by task 19343 on cpu 1:
 vm_area_dup+0x70/0xf0 kernel/fork.c:362
 __split_vma+0x88/0x350 mm/mmap.c:2646
 split_vma+0x73/0xa0 mm/mmap.c:2704
 mprotect_fixup+0x43f/0x510 mm/mprotect.c:413
 do_mprotect_pkey+0x3eb/0x660 mm/mprotect.c:553
 __do_sys_mprotect mm/mprotect.c:578 [inline]
 __se_sys_mprotect mm/mprotect.c:575 [inline]
 __x64_sys_mprotect+0x51/0x70 mm/mprotect.c:575
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19343 Comm: blkid Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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