==================================================================
BUG: KASAN: use-after-free in skb_copy_bits+0x6f0/0x780 net/core/skbuff.c:2374
Read of size 4 at addr ffff888024e37930 by task kworker/1:20/10693

CPU: 1 PID: 10693 Comm: kworker/1:20 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247
 __kasan_report mm/kasan/report.c:433 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
 skb_copy_bits+0x6f0/0x780 net/core/skbuff.c:2374
 __skb_header_pointer include/linux/skbuff.h:3743 [inline]
 skb_header_pointer include/linux/skbuff.h:3752 [inline]
 do_basic_checks net/netfilter/nf_conntrack_proto_sctp.c:174 [inline]
 nf_conntrack_sctp_packet+0xe34/0x2500 net/netfilter/nf_conntrack_proto_sctp.c:383
 nf_conntrack_handle_packet net/netfilter/nf_conntrack_core.c:1845 [inline]
 nf_conntrack_in+0xfe8/0x15e0 net/netfilter/nf_conntrack_core.c:1918
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xc5/0x1e0 net/netfilter/core.c:619
 nf_hook.constprop.0+0x3ac/0x650 include/linux/netfilter.h:262
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ipv6_rcv+0x9e/0x3c0 net/ipv6/ip6_input.c:297
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5462
 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5576
 process_backlog+0x2a5/0x6c0 net/core/dev.c:6452
 __napi_poll+0xaf/0x440 net/core/dev.c:7020
 napi_poll net/core/dev.c:7087 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7174
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:114 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0xa0/0x180 mm/kasan/generic.c:189
Code: 0f 49 da 49 c1 fb 03 45 85 db 0f 84 cb 00 00 00 45 89 db 4a 8d 14 d8 eb 0d 48 83 c0 08 48 39 d0 0f 84 af 00 00 00 48 83 38 00 <74> ed 48 8d 50 08 eb 09 48 83 c0 01 48 39 d0 74 7a 80 38 00 74 f2
RSP: 0018:ffffc90002bb7bd8 EFLAGS: 00000246
RAX: ffffed100e3359c0 RBX: ffffed100e3359d0 RCX: ffffffff87243239
RDX: ffffed100e3359d0 RSI: 00000000000000c0 RDI: ffff8880719acdc0
RBP: ffffed100e3359b8 R08: 0000000000000001 R09: ffff8880719ace7f
R10: ffffed100e3359cf R11: 0000000000000003 R12: 00000000000000c0
R13: 0000000000000000 R14: 0000000000000a20 R15: 0000000000001000
 memset+0x20/0x40 mm/kasan/shadow.c:44
 memset include/linux/fortify-string.h:209 [inline]
 __alloc_skb+0x119/0x340 net/core/skbuff.c:442
 alloc_skb include/linux/skbuff.h:1126 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:745 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:802 [inline]
 nsim_dev_trap_report_work+0x29a/0xbc0 drivers/net/netdevsim/dev.c:843
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Allocated by task 29206:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:3234 [inline]
 kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3270
 __alloc_skb+0x215/0x340 net/core/skbuff.c:414
 alloc_skb include/linux/skbuff.h:1126 [inline]
 sctp_packet_pack net/sctp/output.c:471 [inline]
 sctp_packet_transmit+0xcca/0x3070 net/sctp/output.c:620
 sctp_packet_transmit_chunk+0x114/0x260 net/sctp/output.c:193
 sctp_outq_flush_data+0xa1a/0x26c0 net/sctp/outqueue.c:1101
 sctp_outq_flush net/sctp/outqueue.c:1207 [inline]
 sctp_outq_uncork+0x178/0x200 net/sctp/outqueue.c:758
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1812 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1195 [inline]
 sctp_do_sm+0x745/0x4ed0 net/sctp/sm_sideeffect.c:1166
 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1054
 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80
 sctp_backlog_rcv+0x19e/0x5b0 net/sctp/input.c:344
 sk_backlog_rcv include/net/sock.h:1030 [inline]
 __release_sock+0x134/0x3b0 net/core/sock.c:2768
 release_sock+0x54/0x1b0 net/core/sock.c:3300
 sctp_wait_for_connect+0x1cb/0x5d0 net/sctp/socket.c:9306
 sctp_sendmsg_to_asoc+0x1828/0x2390 net/sctp/socket.c:1881
 sctp_sendmsg+0x103b/0x1d30 net/sctp/socket.c:2027
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 __sys_sendto+0x21c/0x320 net/socket.c:2036
 __do_sys_sendto net/socket.c:2048 [inline]
 __se_sys_sendto net/socket.c:2044 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 29206:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749
 slab_free mm/slub.c:3513 [inline]
 kmem_cache_free+0xbd/0x5d0 mm/slub.c:3530
 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:700
 __kfree_skb net/core/skbuff.c:757 [inline]
 consume_skb net/core/skbuff.c:912 [inline]
 consume_skb+0xcf/0x160 net/core/skbuff.c:906
 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1503 [inline]
 sctp_chunk_put+0x1c0/0x2d0 net/sctp/sm_make_chunk.c:1530
 sctp_inq_free+0x17f/0x260 net/sctp/inqueue.c:56
 sctp_association_free+0x229/0x7d0 net/sctp/associola.c:348
 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:940 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1324 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1195 [inline]
 sctp_do_sm+0x3665/0x4ed0 net/sctp/sm_sideeffect.c:1166
 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1054
 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80
 sctp_backlog_rcv+0x19e/0x5b0 net/sctp/input.c:344
 sk_backlog_rcv include/net/sock.h:1030 [inline]
 __release_sock+0x134/0x3b0 net/core/sock.c:2768
 release_sock+0x54/0x1b0 net/core/sock.c:3300
 sctp_wait_for_connect+0x1cb/0x5d0 net/sctp/socket.c:9306
 sctp_sendmsg_to_asoc+0x1828/0x2390 net/sctp/socket.c:1881
 sctp_sendmsg+0x103b/0x1d30 net/sctp/socket.c:2027
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 __sys_sendto+0x21c/0x320 net/socket.c:2036
 __do_sys_sendto net/socket.c:2048 [inline]
 __se_sys_sendto net/socket.c:2044 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888024e378c0
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 112 bytes inside of
 232-byte region [ffff888024e378c0, ffff888024e379a8)
The buggy address belongs to the page:
page:ffffea0000938dc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24e37
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff8881447ce140
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 29206, ts 616865390957, free_ts 614461187178
 prep_new_page mm/page_alloc.c:2418 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369
 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191
 alloc_slab_page mm/slub.c:1793 [inline]
 allocate_slab mm/slub.c:1930 [inline]
 new_slab+0x32d/0x4a0 mm/slub.c:1993
 ___slab_alloc+0x918/0xfe0 mm/slub.c:3022
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3109
 slab_alloc_node mm/slub.c:3200 [inline]
 slab_alloc mm/slub.c:3242 [inline]
 kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3247
 skb_clone+0x170/0x3c0 net/core/skbuff.c:1521
 sctp_ulpevent_make_rcvmsg+0x2aa/0xb40 net/sctp/ulpevent.c:701
 sctp_ulpq_tail_data+0xa6/0xec0 net/sctp/ulpqueue.c:93
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1454 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1195 [inline]
 sctp_do_sm+0x389b/0x4ed0 net/sctp/sm_sideeffect.c:1166
 sctp_assoc_bh_rcv+0x386/0x6c0 net/sctp/associola.c:1054
 sctp_inq_push+0x1da/0x270 net/sctp/inqueue.c:80
 sctp_backlog_rcv+0x19e/0x5b0 net/sctp/input.c:344
 sk_backlog_rcv include/net/sock.h:1030 [inline]
 __release_sock+0x134/0x3b0 net/core/sock.c:2768
 release_sock+0x54/0x1b0 net/core/sock.c:3300
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1338 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389
 free_unref_page_prepare mm/page_alloc.c:3309 [inline]
 free_unref_page_list+0x1a9/0xfa0 mm/page_alloc.c:3425
 release_pages+0x3f4/0x1480 mm/swap.c:980
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:242 [inline]
 tlb_flush_mmu mm/mmu_gather.c:249 [inline]
 tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:340
 exit_mmap+0x1ea/0x630 mm/mmap.c:3172
 __mmput+0x122/0x4b0 kernel/fork.c:1113
 mmput+0x56/0x60 kernel/fork.c:1134
 exit_mm kernel/exit.c:507 [inline]
 do_exit+0xb27/0x2b40 kernel/exit.c:819
 do_group_exit+0x125/0x310 kernel/exit.c:929
 get_signal+0x47d/0x2220 kernel/signal.c:2852
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Memory state around the buggy address:
 ffff888024e37800: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
 ffff888024e37880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff888024e37900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888024e37980: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff888024e37a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	0f 49 da             	cmovns %edx,%ebx
   3:	49 c1 fb 03          	sar    $0x3,%r11
   7:	45 85 db             	test   %r11d,%r11d
   a:	0f 84 cb 00 00 00    	je     0xdb
  10:	45 89 db             	mov    %r11d,%r11d
  13:	4a 8d 14 d8          	lea    (%rax,%r11,8),%rdx
  17:	eb 0d                	jmp    0x26
  19:	48 83 c0 08          	add    $0x8,%rax
  1d:	48 39 d0             	cmp    %rdx,%rax
  20:	0f 84 af 00 00 00    	je     0xd5
  26:	48 83 38 00          	cmpq   $0x0,(%rax)
* 2a:	74 ed                	je     0x19 <-- trapping instruction
  2c:	48 8d 50 08          	lea    0x8(%rax),%rdx
  30:	eb 09                	jmp    0x3b
  32:	48 83 c0 01          	add    $0x1,%rax
  36:	48 39 d0             	cmp    %rdx,%rax
  39:	74 7a                	je     0xb5
  3b:	80 38 00             	cmpb   $0x0,(%rax)
  3e:	74 f2                	je     0x32