============================= WARNING: suspicious RCU usage 6.16.0-rc4-next-20250702-syzkaller #0 Not tainted ----------------------------- fs/proc/proc_sysctl.c:934 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-executor/5839: #0: ffff88807f900428 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557 #1: ffff88802329ac10 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline] #1: ffff88802329ac10 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: open_last_lookups fs/namei.c:3806 [inline] #1: ffff88802329ac10 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: path_openat+0x8cb/0x3830 fs/namei.c:4043 #2: ffff8880721aa828 (&lockref->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffff8880721aa828 (&lockref->lock){+.+.}-{3:3}, at: d_wait_lookup fs/dcache.c:2537 [inline] #2: ffff8880721aa828 (&lockref->lock){+.+.}-{3:3}, at: d_alloc_parallel+0xbe4/0x15e0 fs/dcache.c:2624 stack backtrace: CPU: 0 UID: 0 PID: 5839 Comm: syz-executor Not tainted 6.16.0-rc4-next-20250702-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 lockdep_rcu_suspicious+0x140/0x1d0 kernel/locking/lockdep.c:6871 proc_sys_compare+0x27d/0x2c0 fs/proc/proc_sysctl.c:934 d_same_name fs/dcache.c:2179 [inline] d_alloc_parallel+0x1060/0x15e0 fs/dcache.c:2637 lookup_open fs/namei.c:3630 [inline] open_last_lookups fs/namei.c:3807 [inline] path_openat+0xa3b/0x3830 fs/namei.c:4043 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1434 do_sys_open fs/open.c:1449 [inline] __do_sys_openat fs/open.c:1465 [inline] __se_sys_openat fs/open.c:1460 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1460 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5fce98d290 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 49 94 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 9c 94 02 00 8b 44 RSP: 002b:00007fff936aacd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007f5fce98d290 RDX: 0000000000080001 RSI: 00007f5fcea2ae65 RDI: 00000000ffffff9c RBP: 00007f5fcea2ae65 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004 R13: 00007fff936aad70 R14: 0000000000000009 R15: 0000000000000000 chnl_net:caif_netlink_parms(): no params data found bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered disabled state bridge_slave_0: entered allmulticast mode bridge_slave_0: entered promiscuous mode bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered disabled state bridge_slave_1: entered allmulticast mode bridge_slave_1: entered promiscuous mode bond0: (slave bond_slave_0): Enslaving as an active interface with an up link bond0: (slave bond_slave_1): Enslaving as an active interface with an up link team0: Port device team_slave_0 added team0: Port device team_slave_1 added batman_adv: batadv0: Adding interface: batadv_slave_0 batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active batman_adv: batadv0: Adding interface: batadv_slave_1 batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active hsr_slave_0: entered promiscuous mode hsr_slave_1: entered promiscuous mode debugfs: 'hsr0' already exists in 'hsr' Cannot create hsr debugfs directory netdevsim netdevsim3 netdevsim0: renamed from eth0 netdevsim netdevsim3 netdevsim1: renamed from eth1 netdevsim netdevsim3 netdevsim2: renamed from eth2 netdevsim netdevsim3 netdevsim3: renamed from eth3 8021q: adding VLAN 0 to HW filter on device bond0 8021q: adding VLAN 0 to HW filter on device team0 8021q: adding VLAN 0 to HW filter on device batadv0 veth0_vlan: entered promiscuous mode veth1_vlan: entered promiscuous mode veth0_macvtap: entered promiscuous mode veth1_macvtap: entered promiscuous mode batman_adv: batadv0: Interface activated: batadv_slave_0 batman_adv: batadv0: Interface activated: batadv_slave_1