syzbot

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BUG: KCSAN: data-race in call_rcu / mtree_range_walk

write to 0xffff888103779b08 of 8 bytes by task 4312 on cpu 0:
 __call_rcu_common kernel/rcu/tree.c:3081 [inline]
 call_rcu+0x49/0x430 kernel/rcu/tree.c:3202
 ma_free_rcu lib/maple_tree.c:211 [inline]
 mas_topiary_node lib/maple_tree.c:2519 [inline]
 mas_topiary_replace lib/maple_tree.c:2625 [inline]
 mas_wmb_replace+0xff5/0x1510 lib/maple_tree.c:2641
 mas_split lib/maple_tree.c:3368 [inline]
 mas_commit_b_node lib/maple_tree.c:3388 [inline]
 mas_wr_bnode lib/maple_tree.c:4049 [inline]
 mas_wr_store_entry+0x158c/0x2460 lib/maple_tree.c:4090
 mas_store_prealloc+0x6d5/0x960 lib/maple_tree.c:5475
 vma_iter_store_overwrite mm/vma.h:448 [inline]
 vma_iter_store_new+0x1d3/0x210 mm/vma.h:455
 vma_complete+0x12b/0x570 mm/vma.c:323
 __split_vma+0x56c/0x630 mm/vma.c:523
 split_vma mm/vma.c:553 [inline]
 vma_modify+0x105/0x200 mm/vma.c:1579
 vma_modify_flags+0x10a/0x140 mm/vma.c:1605
 mprotect_fixup+0x30f/0x5d0 mm/mprotect.c:658
 do_mprotect_pkey+0x6ce/0x9a0 mm/mprotect.c:832
 __do_sys_mprotect mm/mprotect.c:853 [inline]
 __se_sys_mprotect mm/mprotect.c:850 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:850
 x64_sys_call+0x272f/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103779b08 of 8 bytes by task 4321 on cpu 1:
 mtree_range_walk+0x143/0x460 lib/maple_tree.c:2769
 mas_state_walk lib/maple_tree.c:3605 [inline]
 mas_walk+0x16e/0x320 lib/maple_tree.c:4905
 lock_vma_under_rcu+0xa7/0x340 mm/memory.c:6553
 do_user_addr_fault arch/x86/mm/fault.c:1328 [inline]
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x150/0x6a0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x000000110c22ffff -> 0xffff888103779008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4321 Comm: syz.0.294 Not tainted 6.15.0-rc3-syzkaller-00001-g9d7a0577c9db #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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