=============================
WARNING: suspicious RCU usage
6.2.0-rc7-syzkaller-00011-g05ecb680708a #0 Not tainted
-----------------------------
lib/maple_tree.c:852 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.3/11686:
 #0: ffff88802ac69268 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x242/0x2e0 fs/file.c:1046
 #1: ffff88802d598460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x275/0xbb0 fs/read_write.c:580
 #2: ffff88801dc39088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1f3/0x500 fs/kernfs/file.c:325
 #3: ffff8881452543a8 (kn->active#62){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x217/0x500 fs/kernfs/file.c:326
 #4: ffffffff8d60e508 (ksm_thread_mutex){+.+.}-{3:3}, at: run_store+0xfa/0x390 mm/ksm.c:2951
 #5: ffff88802196e198 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
 #5: ffff88802196e198 (&mm->mmap_lock){++++}-{3:3}, at: unmerge_and_remove_all_rmap_items+0x16a/0x8b0 mm/ksm.c:990

stack backtrace:
CPU: 1 PID: 11686 Comm: syz-executor.3 Not tainted 6.2.0-rc7-syzkaller-00011-g05ecb680708a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 mas_root lib/maple_tree.c:852 [inline]
 mas_start lib/maple_tree.c:1357 [inline]
 mas_state_walk lib/maple_tree.c:3838 [inline]
 mas_walk+0x399/0x5b0 lib/maple_tree.c:5046
 mas_find+0x1bb/0x210 lib/maple_tree.c:6012
 vma_find include/linux/mm.h:668 [inline]
 vma_next include/linux/mm.h:677 [inline]
 unmerge_and_remove_all_rmap_items+0x18a/0x8b0 mm/ksm.c:991
 run_store+0x1c9/0x390 mm/ksm.c:2957
 kernfs_fop_write_iter+0x3ac/0x500 fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7b5/0xbb0 fs/read_write.c:584
 ksys_write+0x19b/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8266e8c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8267c10168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8266fabf80 RCX: 00007f8266e8c0f9
RDX: 0000000000000002 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00007f8266ee7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff3a4a9a9f R14: 00007f8267c10300 R15: 0000000000022000
 </TASK>