============================= [ BUG: Invalid wait context ] syzkaller #0 Tainted: G L ----------------------------- syz.4.1733/12064 is trying to lock: ffff888057de52a0 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819 other info that might help us debug this: context-{2:2} 3 locks held by syz.4.1733/12064: #0: ffff88803ee50f60 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline] #0: ffff88803ee50f60 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x20/0x50 net/ipv4/tcp.c:1454 #1: ffffffff8e7e6fe0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffffff8e7e6fe0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #1: ffffffff8e7e6fe0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline] #1: ffffffff8e7e6fe0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x2090 arch/x86/kernel/unwind_orc.c:495 #2: ffff888057de57e8 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline] #2: ffff888057de57e8 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline] #2: ffff888057de57e8 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x245/0xe80 arch/x86/kvm/xen.c:1817 stack backtrace: CPU: 1 UID: 0 PID: 12064 Comm: syz.4.1733 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_lock_invalid_wait_context kernel/locking/lockdep.c:4830 [inline] check_wait_context kernel/locking/lockdep.c:4902 [inline] __lock_acquire+0xfa4/0x2630 kernel/locking/lockdep.c:5187 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline] _raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:240 kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819 xen_timer_callback+0x1db/0x2a0 arch/x86/kvm/xen.c:140 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x142/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 bb 2d 2e 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 86 0c f7 0e 0f 82 a4 02 00 00 8b 35 0e 40 f7 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d 2d 2e 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc90005b4f4e0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8df2a4d9 RDI: ffffffff8c1bf200 RBP: ffffffff8e7e6fe0 R08: 00000000b7862b3d R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_node_noprof+0x25a/0x6f0 mm/slub.c:4950 kmalloc_reserve+0x148/0x350 net/core/skbuff.c:613 __alloc_skb+0x185/0x710 net/core/skbuff.c:713 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x34/0x660 net/ipv4/tcp.c:935 tcp_sendmsg_locked+0x13cd/0x4500 net/ipv4/tcp.c:1260 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1455 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:866 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x446/0x4b0 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2268 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3d7b39c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3d7c24d028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f3d7b616090 RCX: 00007f3d7b39c819 RDX: ffffffffffffff94 RSI: 0000200000000000 RDI: 0000000000000005 RBP: 00007f3d7b432c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0400000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3d7b616128 R14: 00007f3d7b616090 R15: 00007ffdefe76de8 ---------------- Code disassembly (best guess): 0: 05 bb 2d 2e 12 add $0x122e2dbb,%eax 5: 83 f8 07 cmp $0x7,%eax 8: 0f 87 d9 02 00 00 ja 0x2e7 e: 48 0f a3 05 86 0c f7 bt %rax,0xef70c86(%rip) # 0xef70c9c 15: 0e 16: 0f 82 a4 02 00 00 jb 0x2c0 1c: 8b 35 0e 40 f7 0e mov 0xef7400e(%rip),%esi # 0xef74030 22: 85 f6 test %esi,%esi 24: 0f 85 bf 00 00 00 jne 0xe9 * 2a: 48 8b 44 24 30 mov 0x30(%rsp),%rax <-- trapping instruction 2f: 65 48 2b 05 5d 2d 2e sub %gs:0x122e2d5d(%rip),%rax # 0x122e2d94 36: 12 37: 0f 85 ed 02 00 00 jne 0x32a 3d: 48 rex.W 3e: 83 .byte 0x83 3f: c4 .byte 0xc4