====================================================== WARNING: possible circular locking dependency detected 4.17.0-rc6+ #91 Not tainted ------------------------------------------------------ syz-executor7/7098 is trying to acquire lock: 000000001bbad72e (&(&u->lock)->rlock/1){+.+.}, at: sk_diag_dump_icons net/unix/diag.c:82 [inline] 000000001bbad72e (&(&u->lock)->rlock/1){+.+.}, at: sk_diag_fill.isra.5+0xa43/0x10d0 net/unix/diag.c:144 but task is already holding lock: 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline] 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: sk_diag_dump_icons net/unix/diag.c:64 [inline] 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: sk_diag_fill.isra.5+0x94e/0x10d0 net/unix/diag.c:144 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rlock-AF_UNIX){+.+.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 skb_queue_tail+0x26/0x150 net/core/skbuff.c:2900 unix_dgram_sendmsg+0xf77/0x1730 net/unix/af_unix.c:1797 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 ___sys_sendmsg+0x525/0x940 net/socket.c:2117 __sys_sendmmsg+0x3bb/0x6f0 net/socket.c:2205 __compat_sys_sendmmsg net/compat.c:770 [inline] __do_compat_sys_sendmmsg net/compat.c:777 [inline] __se_compat_sys_sendmmsg net/compat.c:774 [inline] __ia32_compat_sys_sendmmsg+0x9f/0x100 net/compat.c:774 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 -> #0 (&(&u->lock)->rlock/1){+.+.}: lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 _raw_spin_lock_nested+0x28/0x40 kernel/locking/spinlock.c:354 sk_diag_dump_icons net/unix/diag.c:82 [inline] sk_diag_fill.isra.5+0xa43/0x10d0 net/unix/diag.c:144 sk_diag_dump net/unix/diag.c:178 [inline] unix_diag_dump+0x35f/0x550 net/unix/diag.c:206 netlink_dump+0x507/0xd20 net/netlink/af_netlink.c:2226 __netlink_dump_start+0x51a/0x780 net/netlink/af_netlink.c:2323 netlink_dump_start include/linux/netlink.h:214 [inline] unix_diag_handler_dump+0x3f4/0x7b0 net/unix/diag.c:307 __sock_diag_cmd net/core/sock_diag.c:230 [inline] sock_diag_rcv_msg+0x2e0/0x3d0 net/core/sock_diag.c:261 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:272 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 sock_write_iter+0x35a/0x5a0 net/socket.c:908 call_write_iter include/linux/fs.h:1784 [inline] do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680 do_iter_write+0x185/0x5f0 fs/read_write.c:959 compat_writev+0x206/0x3f0 fs/read_write.c:1273 do_compat_writev+0x113/0x240 fs/read_write.c:1294 __do_compat_sys_writev fs/read_write.c:1305 [inline] __se_compat_sys_writev fs/read_write.c:1301 [inline] __ia32_compat_sys_writev+0x74/0xb0 fs/read_write.c:1301 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rlock-AF_UNIX); lock(&(&u->lock)->rlock/1); lock(rlock-AF_UNIX); lock(&(&u->lock)->rlock/1); *** DEADLOCK *** 5 locks held by syz-executor7/7098: #0: 00000000239d4904 (sock_diag_mutex){+.+.}, at: sock_diag_rcv+0x1b/0x40 net/core/sock_diag.c:271 #1: 000000003ce9e33d (sock_diag_table_mutex){+.+.}, at: __sock_diag_cmd net/core/sock_diag.c:225 [inline] #1: 000000003ce9e33d (sock_diag_table_mutex){+.+.}, at: sock_diag_rcv_msg+0x169/0x3d0 net/core/sock_diag.c:261 #2: 000000001247f08d (nlk_cb_mutex-SOCK_DIAG){+.+.}, at: netlink_dump+0x98/0xd20 net/netlink/af_netlink.c:2182 #3: 00000000d748d562 (unix_table_lock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline] #3: 00000000d748d562 (unix_table_lock){+.+.}, at: unix_diag_dump+0x10a/0x550 net/unix/diag.c:192 #4: 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline] #4: 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: sk_diag_dump_icons net/unix/diag.c:64 [inline] #4: 0000000007a77f09 (rlock-AF_UNIX){+.+.}, at: sk_diag_fill.isra.5+0x94e/0x10d0 net/unix/diag.c:144 stack backtrace: CPU: 0 PID: 7098 Comm: syz-executor7 Not tainted 4.17.0-rc6+ #91 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_circular_bug.isra.36.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1223 check_prev_add kernel/locking/lockdep.c:1863 [inline] check_prevs_add kernel/locking/lockdep.c:1976 [inline] validate_chain kernel/locking/lockdep.c:2417 [inline] __lock_acquire+0x343e/0x5140 kernel/locking/lockdep.c:3431 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 _raw_spin_lock_nested+0x28/0x40 kernel/locking/spinlock.c:354 sk_diag_dump_icons net/unix/diag.c:82 [inline] sk_diag_fill.isra.5+0xa43/0x10d0 net/unix/diag.c:144 sk_diag_dump net/unix/diag.c:178 [inline] unix_diag_dump+0x35f/0x550 net/unix/diag.c:206 netlink_dump+0x507/0xd20 net/netlink/af_netlink.c:2226 __netlink_dump_start+0x51a/0x780 net/netlink/af_netlink.c:2323 netlink_dump_start include/linux/netlink.h:214 [inline] unix_diag_handler_dump+0x3f4/0x7b0 net/unix/diag.c:307 __sock_diag_cmd net/core/sock_diag.c:230 [inline] sock_diag_rcv_msg+0x2e0/0x3d0 net/core/sock_diag.c:261 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:272 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 sock_write_iter+0x35a/0x5a0 net/socket.c:908 call_write_iter include/linux/fs.h:1784 [inline] do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680 do_iter_write+0x185/0x5f0 fs/read_write.c:959 compat_writev+0x206/0x3f0 fs/read_write.c:1273 do_compat_writev+0x113/0x240 fs/read_write.c:1294 __do_compat_sys_writev fs/read_write.c:1305 [inline] __se_compat_sys_writev fs/read_write.c:1301 [inline] __ia32_compat_sys_writev+0x74/0xb0 fs/read_write.c:1301 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f18cb9 RSP: 002b:00000000f5f140ac EFLAGS: 00000282 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 00000000200000c0 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 8740 Comm: syz-executor5 Not tainted 4.17.0-rc6+ #91 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1522 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc_node mm/slab.c:3299 [inline] kmem_cache_alloc_node+0x272/0x780 mm/slab.c:3642 __alloc_skb+0x111/0x780 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:987 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline] netlink_sendmsg+0xb01/0xfa0 net/netlink/af_netlink.c:1876 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 ___sys_sendmsg+0x805/0x940 net/socket.c:2117 __sys_sendmsg+0x115/0x270 net/socket.c:2155 __compat_sys_sendmsg net/compat.c:756 [inline] __do_compat_sys_sendmsg net/compat.c:763 [inline] __se_compat_sys_sendmsg net/compat.c:760 [inline] __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:760 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f48cb9 RSP: 002b:00000000f5f440ac EFLAGS: 00000282 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000200 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 8768 Comm: syz-executor5 Not tainted 4.17.0-rc6+ #91 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1522 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc_node mm/slab.c:3299 [inline] kmem_cache_alloc_node_trace+0x26f/0x770 mm/slab.c:3661 __do_kmalloc_node mm/slab.c:3681 [inline] __kmalloc_node_track_caller+0x33/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.38+0x3a/0xe0 net/core/skbuff.c:137 __alloc_skb+0x14d/0x780 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:987 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline] netlink_sendmsg+0xb01/0xfa0 net/netlink/af_netlink.c:1876 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 ___sys_sendmsg+0x805/0x940 net/socket.c:2117 __sys_sendmsg+0x115/0x270 net/socket.c:2155 __compat_sys_sendmsg net/compat.c:756 [inline] __do_compat_sys_sendmsg net/compat.c:763 [inline] __se_compat_sys_sendmsg net/compat.c:760 [inline] __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:760 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f48cb9 RSP: 002b:00000000f5f440ac EFLAGS: 00000282 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000200 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 8806 Comm: syz-executor1 Not tainted 4.17.0-rc6+ #91 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1522 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc_node mm/slab.c:3299 [inline] kmem_cache_alloc_node+0x272/0x780 mm/slab.c:3642 __alloc_skb+0x111/0x780 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:987 [inline] pfkey_sendmsg+0x250/0x1050 net/key/af_key.c:3670 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 ___sys_sendmsg+0x805/0x940 net/socket.c:2117 __sys_sendmsg+0x115/0x270 net/socket.c:2155 __compat_sys_sendmsg net/compat.c:756 [inline] __do_compat_sys_sendmsg net/compat.c:763 [inline] __se_compat_sys_sendmsg net/compat.c:760 [inline] __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:760 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394