[moderation] [mm?] KCSAN: data-race in mas_state_walk / mas_wr_store_entry

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5bc1018675ec Merge tag 'pci-v6.15-fixes-3' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17ed9d74580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fc7049672597c030
dashboard link: https://syzkaller.appspot.com/bug?extid=ff9c72a9eb3dc1c87021
compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
CC: [Liam.H...@oracle.com ak...@linux-foundation.org ja...@google.com linux-...@vger.kernel.org linu...@kvack.org lorenzo...@oracle.com pfal...@suse.de vba...@suse.cz]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b07ed9969a13/disk-5bc10186.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3abab03798d3/vmlinux-5bc10186.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8fca26b1845c/bzImage-5bc10186.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ff9c72...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mas_state_walk / mas_wr_store_entry

write to 0xffff88810445d260 of 8 bytes by task 5171 on cpu 0:
mas_wr_slot_store lib/maple_tree.c:3895 [inline]
mas_wr_store_entry+0x15cc/0x2b60 lib/maple_tree.c:4080
mas_store_prealloc+0x74d/0x9e0 lib/maple_tree.c:5475
vma_iter_store_overwrite mm/vma.h:448 [inline]
commit_merge+0x66e/0x6f0 mm/vma.c:709
vma_expand+0x1d0/0x370 mm/vma.c:1114
vma_merge_new_range+0x296/0x310 mm/vma.c:1052
__mmap_region mm/vma.c:2514 [inline]
mmap_region+0x7e6/0x1470 mm/vma.c:2597
do_mmap+0x9de/0xc20 mm/mmap.c:561
vm_mmap_pgoff+0x17a/0x2e0 mm/util.c:579
ksys_mmap_pgoff+0xc2/0x310 mm/mmap.c:607
x64_sys_call+0x1602/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:10
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810445d260 of 8 bytes by task 5175 on cpu 1:
mtree_range_walk lib/maple_tree.c:2777 [inline]
mas_state_walk+0x2f5/0x650 lib/maple_tree.c:3605
mas_walk+0x30/0x120 lib/maple_tree.c:4905
lock_vma_under_rcu+0xa2/0x2f0 mm/memory.c:6553
do_user_addr_fault+0x233/0x1090 arch/x86/mm/fault.c:1328
handle_page_fault arch/x86/mm/fault.c:1480 [inline]
exc_page_fault+0x54/0xc0 arch/x86/mm/fault.c:1538
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x00007f4fe2444fff -> 0x00007f4fe2423fff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5175 Comm: syz.2.556 Not tainted 6.15.0-rc3-syzkaller-00342-g5bc1018675ec #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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