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BUG: KASAN: out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc900016f7830 by task syz-executor.5/25883

CPU: 1 PID: 25883 Comm: syz-executor.5 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:insert_header+0x4cf/0xfa0 fs/proc/proc_sysctl.c:237
Code: 89 44 24 20 e8 b2 bc c9 01 48 83 44 24 10 40 48 8b 44 24 10 48 c1 e8 03 80 3c 28 00 0f 85 78 08 00 00 48 8b 44 24 10 4c 8b 38 <4d> 85 ff 0f 84 3b 06 00 00 e8 43 dc 8c ff 48 8b 04 24 48 c1 e8 03
RSP: 0018:ffffc90015d07800 EFLAGS: 00000246
RAX: ffff888045e60440 RBX: ffff8880a19a3860 RCX: ffffc9001a215000
RDX: 1ffff11002b2dc4a RSI: ffff8880901e1650 RDI: ffff88801596e250
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffff9
R13: ffff8880a19a3850 R14: 0000000000000013 R15: ffffffff89084ba0
 __register_sysctl_table+0x65a/0x1090 fs/proc/proc_sysctl.c:1349
 ipv4_sysctl_init_net+0xb5/0x310 net/ipv4/sysctl_net_ipv4.c:1376
 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
 copy_namespaces+0x385/0x470 kernel/nsproxy.c:179
 copy_process+0x2921/0x6b90 kernel/fork.c:2083
 _do_fork+0x12c/0xa70 kernel/fork.c:2425
 __do_sys_clone+0xef/0x150 kernel/fork.c:2581
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007fb180313c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00000000004db5a0 RCX: 000000000045cb29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000048b88100
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000007c R14: 00000000004c34ba R15: 00007fb1803146d4


Memory state around the buggy address:
 ffffc900016f7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900016f7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900016f7800: f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3 00 00 00 00
                                        ^
 ffffc900016f7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900016f7900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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