=============================
WARNING: suspicious RCU usage
6.3.0-rc1-syzkaller-gfe15c26ee26e #0 Not tainted
-----------------------------
lib/maple_tree.c:856 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
6 locks held by syz-executor.5/10054:
 #0: ffff0000d9e32ae8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xd8/0x104 fs/file.c:1046
 #1: ffff0000d90f0460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x244/0x914 fs/read_write.c:580
 #2: ffff0000fc8b9088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c8/0x48c fs/kernfs/file.c:325
 #3: ffff0000c10d1da0 (kn->active#55){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1e4/0x48c fs/kernfs/file.c:326
 #4: ffff800015f912c8 (ksm_thread_mutex){+.+.}-{3:3}, at: run_store+0x10c/0xa1c mm/ksm.c:2953
 #5: ffff0000da0537c8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
 #5: ffff0000da0537c8 (&mm->mmap_lock){++++}-{3:3}, at: unmerge_and_remove_all_rmap_items mm/ksm.c:990 [inline]
 #5: ffff0000da0537c8 (&mm->mmap_lock){++++}-{3:3}, at: run_store+0x274/0xa1c mm/ksm.c:2959

stack backtrace:
CPU: 0 PID: 10054 Comm: syz-executor.5 Not tainted 6.3.0-rc1-syzkaller-gfe15c26ee26e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 dump_stack+0x1c/0x28 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x260/0x464 kernel/locking/lockdep.c:6599
 mas_root lib/maple_tree.c:856 [inline]
 mas_start+0x278/0x3c8 lib/maple_tree.c:1357
 mas_state_walk lib/maple_tree.c:3838 [inline]
 mas_walk+0x4c/0x1a4 lib/maple_tree.c:5052
 mas_find+0x1e4/0x228 lib/maple_tree.c:6030
 vma_next include/linux/mm.h:745 [inline]
 unmerge_and_remove_all_rmap_items mm/ksm.c:991 [inline]
 run_store+0x28c/0xa1c mm/ksm.c:2959
 kobj_attr_store+0x6c/0x90 lib/kobject.c:832
 sysfs_kf_write+0x200/0x280 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x610/0x914 fs/read_write.c:584
 ksys_write+0x15c/0x26c fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591