================================================================== BUG: KCSAN: data-race in pcpu_alloc / pcpu_free_area write to 0xffffffff8455f74c of 4 bytes by task 27845 on cpu 0: pcpu_update_empty_pages mm/percpu.c:559 [inline] pcpu_block_update_hint_free mm/percpu.c:994 [inline] pcpu_free_area+0x50c/0x5a0 mm/percpu.c:1254 free_percpu+0x1d2/0x690 mm/percpu.c:2102 xt_percpu_counter_free+0x5f/0x70 net/netfilter/x_tables.c:1889 cleanup_entry+0x15a/0x180 net/ipv4/netfilter/ip_tables.c:655 __do_replace+0x45e/0x580 net/ipv4/netfilter/ip_tables.c:1084 do_replace net/ipv4/netfilter/ip_tables.c:1139 [inline] do_ipt_set_ctl+0x6ac/0x1630 net/ipv4/netfilter/ip_tables.c:1629 nf_setsockopt+0x1a6/0x1c0 net/netfilter/nf_sockopt.c:101 ip_setsockopt+0x2602/0x2a20 net/ipv4/ip_sockglue.c:1435 tcp_setsockopt+0x8c/0xa0 net/ipv4/tcp.c:3655 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3257 __sys_setsockopt+0x18f/0x200 net/socket.c:2117 __do_sys_setsockopt net/socket.c:2128 [inline] __se_sys_setsockopt net/socket.c:2125 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2125 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff8455f74c of 4 bytes by task 11635 on cpu 1: pcpu_alloc+0xa33/0x1200 mm/percpu.c:1835 __alloc_percpu+0x20/0x30 mm/percpu.c:1907 __percpu_init_rwsem+0x15/0x80 kernel/locking/percpu-rwsem.c:15 alloc_super+0x16d/0x520 fs/super.c:235 sget_fc+0x1cf/0x4e0 fs/super.c:531 vfs_get_super fs/super.c:1135 [inline] get_tree_keyed+0x3f/0x120 fs/super.c:1196 mqueue_get_tree+0x32/0x40 ipc/mqueue.c:427 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498 fc_mount+0x12/0x60 fs/namespace.c:993 mq_create_mount ipc/mqueue.c:470 [inline] mq_init_ns+0x26d/0x310 ipc/mqueue.c:1685 create_ipc_ns ipc/namespace.c:58 [inline] copy_ipcs+0x211/0x360 ipc/namespace.c:84 create_new_namespaces+0x137/0x560 kernel/nsproxy.c:90 copy_namespaces+0x111/0x160 kernel/nsproxy.c:178 copy_process+0x1254/0x2e00 kernel/fork.c:2119 kernel_clone+0x14b/0x680 kernel/fork.c:2503 __do_sys_clone kernel/fork.c:2620 [inline] __se_sys_clone kernel/fork.c:2604 [inline] __x64_sys_clone+0xb4/0xe0 kernel/fork.c:2604 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 11635 Comm: syz-executor.3 Tainted: G W 5.12.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================