batman_adv: batadv0: Adding interface: syz_tun
batman_adv: batadv0: The MTU of interface syz_tun 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 1532 would solve the problem.
batman_adv: batadv0: Interface activated: syz_tun
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x410/0x560 lib/fault-inject.c:174
 should_failslab+0xa8/0x100 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4638 [inline]
 slab_alloc_node mm/slub.c:4974 [inline]
 __kmalloc_cache_noprof+0xa3/0x600 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 batadv_orig_ifinfo_new+0x99/0x320 net/batman-adv/originator.c:422
 batadv_iv_ogm_update_seqnos net/batman-adv/bat_iv_ogm.c:1412 [inline]
 batadv_iv_ogm_process_per_outif+0x26b/0x25c0 net/batman-adv/bat_iv_ogm.c:1550
 batadv_iv_ogm_process net/batman-adv/bat_iv_ogm.c:1866 [inline]
 batadv_iv_ogm_receive+0xc13/0x1740 net/batman-adv/bat_iv_ogm.c:1974
 batadv_batman_skb_recv+0x4b6/0x870 net/batman-adv/main.c:529
 __netif_receive_skb_one_core net/core/dev.c:6297 [inline]
 __netif_receive_skb net/core/dev.c:6410 [inline]
 netif_receive_skb_internal net/core/dev.c:6496 [inline]
 netif_receive_skb+0x4af/0xbf0 net/core/dev.c:6555
 tun_rx_batched+0x1de/0x790 drivers/net/tun.c:1571
 tun_get_user+0x2be0/0x44d0 drivers/net/tun.c:2045
 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2091
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68b195e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f68b28d4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f68b28d56c0 RCX: 00007f68b195e98e
RDX: 000000000000003a RSI: 0000200000000640 RDI: 00000000000000c8
RBP: 00007f68b28d5050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f68b1c26038 R14: 00007f68b1c25fa0 R15: 00007fff33087da8
 </TASK>
------------[ cut here ]------------
!orig_ifinfo
WARNING: net/batman-adv/bat_iv_ogm.c:1413 at batadv_iv_ogm_update_seqnos net/batman-adv/bat_iv_ogm.c:1413 [inline], CPU#0: syz.0.0/5324
WARNING: net/batman-adv/bat_iv_ogm.c:1413 at batadv_iv_ogm_process_per_outif+0x1fe4/0x25c0 net/batman-adv/bat_iv_ogm.c:1550, CPU#0: syz.0.0/5324
Modules linked in:
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:batadv_iv_ogm_update_seqnos net/batman-adv/bat_iv_ogm.c:1413 [inline]
RIP: 0010:batadv_iv_ogm_process_per_outif+0x1fe4/0x25c0 net/batman-adv/bat_iv_ogm.c:1550
Code: ff ff e8 4f 04 19 f6 49 bc 00 00 00 00 00 fc ff df e9 80 f4 ff ff e8 3b 04 19 f6 90 0f 0b 90 e9 47 e1 ff ff e8 2d 04 19 f6 90 <0f> 0b 90 48 8b bc 24 80 00 00 00 e8 6c df ff ff 48 c7 44 24 50 00
RSP: 0018:ffffc9000dee72a0 EFLAGS: 00010293
RAX: ffffffff8baefaf3 RBX: ffff88805285e400 RCX: ffff888000a84b00
RDX: 0000000000000000 RSI: ffffffff8e41a20e RDI: ffffffff8c6dcd80
RBP: ffffc9000dee7430 R08: ffffffff907a887f R09: 1ffffffff20f510f
R10: dffffc0000000000 R11: fffffbfff20f5110 R12: dffffc0000000000
R13: 0000000001000000 R14: ffff88801245c000 R15: ffff88805285e400
FS:  00007f68b28d56c0(0000) GS:ffff88808c2bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68b1c27da0 CR3: 000000001396b000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 batadv_iv_ogm_process net/batman-adv/bat_iv_ogm.c:1866 [inline]
 batadv_iv_ogm_receive+0xc13/0x1740 net/batman-adv/bat_iv_ogm.c:1974
 batadv_batman_skb_recv+0x4b6/0x870 net/batman-adv/main.c:529
 __netif_receive_skb_one_core net/core/dev.c:6297 [inline]
 __netif_receive_skb net/core/dev.c:6410 [inline]
 netif_receive_skb_internal net/core/dev.c:6496 [inline]
 netif_receive_skb+0x4af/0xbf0 net/core/dev.c:6555
 tun_rx_batched+0x1de/0x790 drivers/net/tun.c:1571
 tun_get_user+0x2be0/0x44d0 drivers/net/tun.c:2045
 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:2091
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68b195e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f68b28d4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f68b28d56c0 RCX: 00007f68b195e98e
RDX: 000000000000003a RSI: 0000200000000640 RDI: 00000000000000c8
RBP: 00007f68b28d5050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f68b1c26038 R14: 00007f68b1c25fa0 R15: 00007fff33087da8
 </TASK>