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BUG: KCSAN: data-race in mas_state_walk / mas_wmb_replace

write to 0xffff88810481f600 of 8 bytes by task 5142 on cpu 0:
 mas_set_parent lib/maple_tree.c:523 [inline]
 mas_adopt_children lib/maple_tree.c:1535 [inline]
 mas_topiary_replace lib/maple_tree.c:2360 [inline]
 mas_wmb_replace+0x919/0x1610 lib/maple_tree.c:2433
 mas_split lib/maple_tree.c:3052 [inline]
 mas_commit_b_node lib/maple_tree.c:3072 [inline]
 mas_wr_bnode lib/maple_tree.c:3739 [inline]
 mas_wr_store_entry+0x16b6/0x2ed0 lib/maple_tree.c:3771
 mas_store_prealloc+0x72e/0xa70 lib/maple_tree.c:5169
 vma_iter_store_overwrite mm/vma.h:607 [inline]
 vma_iter_store_new mm/vma.h:614 [inline]
 vma_complete+0x3c7/0x850 mm/vma.c:356
 __split_vma+0x593/0x640 mm/vma.c:566
 vms_gather_munmap_vmas+0x184/0x850 mm/vma.c:1408
 do_vmi_align_munmap+0x1e1/0x400 mm/vma.c:1576
 do_vmi_munmap+0x1da/0x220 mm/vma.c:1633
 do_munmap+0x8d/0xc0 mm/mmap.c:1066
 mremap_to+0x1a3/0x440 mm/mremap.c:1378
 do_mremap mm/mremap.c:1941 [inline]
 __do_sys_mremap mm/mremap.c:1997 [inline]
 __se_sys_mremap+0x667/0xb50 mm/mremap.c:1965
 __x64_sys_mremap+0x67/0x80 mm/mremap.c:1965
 x64_sys_call+0x29db/0x3020 arch/x86/include/generated/asm/syscalls_64.h:26
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810481f600 of 8 bytes by task 5141 on cpu 1:
 ma_dead_node lib/maple_tree.c:572 [inline]
 mtree_range_walk lib/maple_tree.c:2580 [inline]
 mas_state_walk+0x485/0x650 lib/maple_tree.c:3298
 mas_walk+0x60/0x150 lib/maple_tree.c:4599
 lock_vma_under_rcu+0xc9/0x210 mm/mmap_lock.c:304
 do_user_addr_fault+0x232/0x1050 arch/x86/mm/fault.c:1325
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0xffff88810481fb16 -> 0xffff888104e20716

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5141 Comm: syz.0.437 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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