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BUG: KASAN: stack-out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc90002d87b10 by task syz-executor883/5490

CPU: 1 PID: 5490 Comm: syz-executor883 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 csd_lock_record+0xcb/0xe0 kernel/smp.c:118
 flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391
 __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_call_function_single+0xe0/0x120 arch/x86/kernel/smp.c:243
 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
RIP: 0010:slab_alloc mm/slab.c:3309 [inline]
RIP: 0010:kmem_cache_alloc+0x397/0x550 mm/slab.c:3486
Code: 4e 7e 0f 85 f0 fd ff ff e8 15 38 4d ff e9 e6 fd ff ff e8 cc 8f c6 ff 48 83 3d f4 bd 01 08 00 0f 84 39 01 00 00 4c 89 e7 57 9d <0f> 1f 44 00 00 e9 7e fd ff ff 31 d2 be 03 02 00 00 48 c7 c7 d5 aa
RSP: 0018:ffffc90012887a40 EFLAGS: 00000282
RAX: 00000000000016a9 RBX: 0000000000000cc0 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000282
RBP: ffff8880a697f800 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000282
R13: ffff88814d50d500 R14: 0000000000000cc0 R15: 0000000000000000
 sk_prot_alloc+0x5f/0x300 net/core/sock.c:1678
 sk_alloc+0x32/0xbd0 net/core/sock.c:1738
 inet6_create net/ipv6/af_inet6.c:183 [inline]
 inet6_create+0x373/0xf90 net/ipv6/af_inet6.c:110
 __sock_create+0x3ca/0x740 net/socket.c:1428
 inet_ctl_sock_create+0x88/0x1d0 net/ipv4/af_inet.c:1655
 dccp_v6_init_net+0x53/0x80 net/dccp/ipv6.c:1104
 ops_init+0xaf/0x470 net/core/net_namespace.c:151
 setup_net+0x2d8/0x850 net/core/net_namespace.c:341
 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:482
 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x445/0x8e0 kernel/fork.c:2966
 __do_sys_unshare kernel/fork.c:3034 [inline]
 __se_sys_unshare kernel/fork.c:3032 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3032
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4459d9
Code: Bad RIP value.
RSP: 002b:00007fff1631c158 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004459d9
RDX: 0000000000405030 RSI: 0000000000000012 RDI: 0000000040000000
RBP: 0000000000000000 R08: 0000000000000004 R09: 00000000000003e8
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000001ec
R13: 00000000004065a0 R14: 0000000000000000 R15: 0000000000000000


Memory state around the buggy address:
 ffffc90002d87a00: f1 f1 00 00 00 00 00 00 00 00 00 00 00 f3 f3 f3
 ffffc90002d87a80: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffffc90002d87b00: f1 f1 f1 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00
                         ^
 ffffc90002d87b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90002d87c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
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