syzkaller login: [  130.130210][   T32] audit: type=1400 audit(1583705033.185:41): avc:  denied  { map } for  pid=12068 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
Warning: Permanently added '10.128.0.229' (ECDSA) to the list of known hosts.
executing program
[  138.529603][   T32] audit: type=1400 audit(1583705041.585:42): avc:  denied  { map } for  pid=12080 comm="syz-executor346" path="/root/syz-executor346902697" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
[  138.554311][T12080] =====================================================
[  138.564181][T12080] BUG: KMSAN: uninit-value in __iptunnel_pull_header+0x30c/0xbd0
[  138.571906][T12080] CPU: 1 PID: 12080 Comm: syz-executor346 Not tainted 5.6.0-rc2-syzkaller #0
[  138.580654][T12080] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[  138.590715][T12080] Call Trace:
[  138.594016][T12080]  dump_stack+0x1c9/0x220
[  138.598353][T12080]  kmsan_report+0xf7/0x1e0
[  138.602890][T12080]  __msan_warning+0x58/0xa0
[  138.607421][T12080]  __iptunnel_pull_header+0x30c/0xbd0
[  138.612822][T12080]  gre_rcv+0x15e/0x19c0
[  138.616977][T12080]  ? __local_bh_enable_ip+0x97/0x1d0
[  138.622300][T12080]  ? ipv6_chk_mcast_addr+0x713/0x7d0
[  138.627605][T12080]  ? kmsan_get_metadata+0x11d/0x180
[  138.632805][T12080]  ip6_protocol_deliver_rcu+0x181b/0x22c0
[  138.638596][T12080]  ? kmsan_get_shadow_origin_ptr+0x81/0xb0
[  138.644427][T12080]  ? ipv6_confirm+0x257/0x650
[  138.649170][T12080]  ip6_mc_input+0xdf2/0x1460
[  138.653828][T12080]  ? ip6_input+0x340/0x340
[  138.658256][T12080]  ? ip6_input_finish+0xa0/0xa0
[  138.663134][T12080]  ipv6_rcv+0x683/0x710
[  138.667307][T12080]  ? local_bh_enable+0x40/0x40
[  138.672070][T12080]  netif_receive_skb+0x66b/0xf20
[  138.677026][T12080]  ? __msan_poison_alloca+0xf0/0x120
[  138.682329][T12080]  tun_get_user+0x6aef/0x6f60
[  138.687076][T12080]  ? kmsan_get_metadata+0x11d/0x180
[  138.692279][T12080]  tun_chr_write_iter+0x1f2/0x360
[  138.697311][T12080]  ? tun_chr_read_iter+0x460/0x460
[  138.702444][T12080]  __vfs_write+0xa5a/0xca0
[  138.706972][T12080]  vfs_write+0x44a/0x8f0
[  138.711227][T12080]  ksys_write+0x267/0x450
[  138.715593][T12080]  __ia32_sys_write+0xdb/0x120
[  138.720369][T12080]  ? __se_sys_write+0xb0/0xb0
[  138.725072][T12080]  do_fast_syscall_32+0x3c7/0x6e0
[  138.730125][T12080]  entry_SYSENTER_compat+0x68/0x77
[  138.735238][T12080] RIP: 0023:0xf7fced99
[  138.739330][T12080] Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
[  138.758938][T12080] RSP: 002b:00000000fff5845c EFLAGS: 00000217 ORIG_RAX: 0000000000000004
[  138.767360][T12080] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020002580
[  138.775354][T12080] RDX: 0000000000000fca RSI: 0000000000000036 RDI: 0000000000000004
[  138.783323][T12080] RBP: 0000000000008914 R08: 0000000000000000 R09: 0000000000000000
[  138.791370][T12080] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[  138.799333][T12080] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[  138.807327][T12080] 
[  138.809639][T12080] Uninit was created at:
[  138.813890][T12080]  kmsan_internal_poison_shadow+0x66/0xd0
[  138.819602][T12080]  kmsan_slab_alloc+0x8a/0xe0
[  138.824288][T12080]  __kmalloc_node_track_caller+0xb40/0x1200
[  138.830186][T12080]  __alloc_skb+0x2fd/0xac0
[  138.834766][T12080]  alloc_skb_with_frags+0x18c/0xa70
[  138.839952][T12080]  sock_alloc_send_pskb+0xada/0xc60
[  138.845151][T12080]  tun_get_user+0x10ae/0x6f60
[  138.849828][T12080]  tun_chr_write_iter+0x1f2/0x360
[  138.854843][T12080]  __vfs_write+0xa5a/0xca0
[  138.859251][T12080]  vfs_write+0x44a/0x8f0
[  138.863488][T12080]  ksys_write+0x267/0x450
[  138.867808][T12080]  __ia32_sys_write+0xdb/0x120
[  138.872574][T12080]  do_fast_syscall_32+0x3c7/0x6e0
[  138.877600][T12080]  entry_SYSENTER_compat+0x68/0x77
[  138.882694][T12080] =====================================================
[  138.889645][T12080] Disabling lock debugging due to kernel taint
[  138.896077][T12080] Kernel panic - not syncing: panic_on_warn set ...
[  138.902787][T12080] CPU: 1 PID: 12080 Comm: syz-executor346 Tainted: G    B             5.6.0-rc2-syzkaller #0
[  138.913017][T12080] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[  138.923070][T12080] Call Trace:
[  138.926367][T12080]  dump_stack+0x1c9/0x220
[  138.930703][T12080]  panic+0x3d5/0xc3e
[  138.934642][T12080]  kmsan_report+0x1df/0x1e0
[  138.939449][T12080]  __msan_warning+0x58/0xa0
[  138.943956][T12080]  __iptunnel_pull_header+0x30c/0xbd0
[  138.949359][T12080]  gre_rcv+0x15e/0x19c0
[  138.953535][T12080]  ? __local_bh_enable_ip+0x97/0x1d0
[  138.958931][T12080]  ? ipv6_chk_mcast_addr+0x713/0x7d0
[  138.964268][T12080]  ? kmsan_get_metadata+0x11d/0x180
[  138.969474][T12080]  ip6_protocol_deliver_rcu+0x181b/0x22c0
[  138.975195][T12080]  ? kmsan_get_shadow_origin_ptr+0x81/0xb0
[  138.981349][T12080]  ? ipv6_confirm+0x257/0x650
[  138.986056][T12080]  ip6_mc_input+0xdf2/0x1460
[  138.990657][T12080]  ? ip6_input+0x340/0x340
[  138.995070][T12080]  ? ip6_input_finish+0xa0/0xa0
[  138.999912][T12080]  ipv6_rcv+0x683/0x710
[  139.004075][T12080]  ? local_bh_enable+0x40/0x40
[  139.008836][T12080]  netif_receive_skb+0x66b/0xf20
[  139.013770][T12080]  ? __msan_poison_alloca+0xf0/0x120
[  139.019060][T12080]  tun_get_user+0x6aef/0x6f60
[  139.023776][T12080]  ? kmsan_get_metadata+0x11d/0x180
[  139.028975][T12080]  tun_chr_write_iter+0x1f2/0x360
[  139.034004][T12080]  ? tun_chr_read_iter+0x460/0x460
[  139.040076][T12080]  __vfs_write+0xa5a/0xca0
[  139.044511][T12080]  vfs_write+0x44a/0x8f0
[  139.048764][T12080]  ksys_write+0x267/0x450
[  139.053105][T12080]  __ia32_sys_write+0xdb/0x120
[  139.057871][T12080]  ? __se_sys_write+0xb0/0xb0
[  139.062539][T12080]  do_fast_syscall_32+0x3c7/0x6e0
[  139.067571][T12080]  entry_SYSENTER_compat+0x68/0x77
[  139.072686][T12080] RIP: 0023:0xf7fced99
[  139.076759][T12080] Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
[  139.096359][T12080] RSP: 002b:00000000fff5845c EFLAGS: 00000217 ORIG_RAX: 0000000000000004
[  139.104891][T12080] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020002580
[  139.112977][T12080] RDX: 0000000000000fca RSI: 0000000000000036 RDI: 0000000000000004
[  139.120946][T12080] RBP: 0000000000008914 R08: 0000000000000000 R09: 0000000000000000
[  139.128918][T12080] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[  139.136896][T12080] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[  139.146677][T12080] Kernel Offset: 0x26400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[  139.158303][T12080] Rebooting in 86400 seconds..