=============================
WARNING: suspicious RCU usage
6.14.0-rc2-next-20250217-syzkaller #0 Not tainted
-----------------------------
fs/kernfs/mount.c:243 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz.4.1320/10287:
 #0: ffff88802a7f0870 (&fc->uapi_mutex){+.+.}-{4:4}, at: __do_sys_fsconfig fs/fsopen.c:465 [inline]
 #0: ffff88802a7f0870 (&fc->uapi_mutex){+.+.}-{4:4}, at: __se_sys_fsconfig+0x9b2/0xf60 fs/fsopen.c:344
 #1: ffff88814dafe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #1: ffff88814dafe0e0 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x196/0x400 fs/super.c:120
 #2: ffff88801bef7148 (&root->kernfs_rwsem){++++}-{4:4}, at: class_rwsem_read_constructor include/linux/rwsem.h:241 [inline]
 #2: ffff88801bef7148 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_node_dentry+0xc3/0x2d0 fs/kernfs/mount.c:223

stack backtrace:
CPU: 1 UID: 0 PID: 10287 Comm: syz.4.1320 Not tainted 6.14.0-rc2-next-20250217-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x226/0x340 kernel/locking/lockdep.c:6847
 kernfs_node_dentry+0x24b/0x2d0 fs/kernfs/mount.c:243
 cgroup_do_get_tree+0x248/0x390 kernel/cgroup/cgroup.c:2233
 cgroup_get_tree+0xbb/0x230 kernel/cgroup/cgroup.c:2272
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759
 vfs_cmd_create+0xa0/0x1f0 fs/fsopen.c:225
 __do_sys_fsconfig fs/fsopen.c:467 [inline]
 __se_sys_fsconfig+0xa33/0xf60 fs/fsopen.c:344
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f32d3b8cde9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f32d4924038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007f32d3da5fa0 RCX: 00007f32d3b8cde9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007f32d3c0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f32d3da5fa0 R15: 00007ffd65273368
 </TASK>

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