[moderation] [mm?] KCSAN: data-race in mtree_range_walk / rcu_segcblist_enqueue

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a7bbe7519b6 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=134a2842180000
kernel config: https://syzkaller.appspot.com/x/.config?x=3cd0dc1b46a5bc5c
dashboard link: https://syzkaller.appspot.com/bug?extid=4097ddb5dd88e13f86e9
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/903440c61bef/disk-4a7bbe75.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9655b05e2f2b/vmlinux-4a7bbe75.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4a4529a3d03b/bzImage-4a7bbe75.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4097dd...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mtree_range_walk / rcu_segcblist_enqueue

write to 0xffff888133b2c308 of 8 bytes by task 20936 on cpu 0:
rcu_segcblist_enqueue+0x67/0xa0 kernel/rcu/rcu_segcblist.c:345
__call_rcu_common kernel/rcu/tree.c:2735 [inline]
call_rcu+0x1ba/0x420 kernel/rcu/tree.c:2829
ma_free_rcu lib/maple_tree.c:197 [inline]
mas_free lib/maple_tree.c:1304 [inline]
mas_replace_node+0x2f8/0x430 lib/maple_tree.c:1741
mas_wr_node_store lib/maple_tree.c:3958 [inline]
mas_wr_modify+0x2bc3/0x3c80 lib/maple_tree.c:4191
mas_wr_store_entry+0x250/0x390 lib/maple_tree.c:4231
mas_store_prealloc+0x151/0x2a0 lib/maple_tree.c:5437
vma_iter_store mm/internal.h:1185 [inline]
vma_complete+0x3a7/0x760 mm/mmap.c:532
__split_vma+0x580/0x610 mm/mmap.c:2381
split_vma mm/mmap.c:2407 [inline]
vma_modify+0x152/0x240 mm/mmap.c:2442
vma_modify_flags include/linux/mm.h:3283 [inline]
mprotect_fixup+0x324/0x5c0 mm/mprotect.c:635
do_mprotect_pkey+0x64c/0x930 mm/mprotect.c:809
__do_sys_mprotect mm/mprotect.c:830 [inline]
__se_sys_mprotect mm/mprotect.c:827 [inline]
__x64_sys_mprotect+0x48/0x50 mm/mprotect.c:827
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888133b2c308 of 8 bytes by task 20939 on cpu 1:
mtree_range_walk+0x2a3/0x450 lib/maple_tree.c:2791
mas_state_walk lib/maple_tree.c:3680 [inline]
mas_walk+0x16e/0x320 lib/maple_tree.c:4861
lock_vma_under_rcu+0x84/0x290 mm/memory.c:5602
do_user_addr_fault arch/x86/mm/fault.c:1356 [inline]
handle_page_fault arch/x86/mm/fault.c:1507 [inline]
exc_page_fault+0x165/0x6d0 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20939 Comm: syz-executor.2 Not tainted 6.8.0-rc3-syzkaller-00279-g4a7bbe7519b6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.