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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 ffffc900010d7550 by task syz-executor.1/8811

CPU: 1 PID: 8811 Comm: syz-executor.1 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:unwind_next_frame+0x950/0x1f90 arch/x86/kernel/unwind_orc.c:469
Code: fc ff df 48 8b 14 24 48 c1 ea 03 80 3c 02 00 0f 85 98 13 00 00 4c 89 c0 49 8b 57 38 48 be 00 00 00 00 00 fc ff df 48 c1 e8 03 <0f> b6 3c 30 49 8d 40 01 49 89 c3 49 c1 eb 03 41 0f b6 34 33 4d 89
RSP: 0018:ffffc90001756fc8 EFLAGS: 00000a03
RAX: 1ffffffff16f28d3 RBX: 1ffff920002eae01 RCX: ffffffff8b7946a1
RDX: ffffc90001757cf0 RSI: dffffc0000000000 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffff8b79469c R09: ffffffff8b7946a0
R10: 000000000007201e R11: 000000000010f52a R12: ffffc900017570e8
R13: ffffc900017570d5 R14: ffffc900017570f0 R15: ffffc900017570a0
 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:494
 slab_post_alloc_hook mm/slab.h:535 [inline]
 slab_alloc_node mm/slab.c:3258 [inline]
 kmem_cache_alloc_node+0x14b/0x580 mm/slab.c:3578
 __alloc_skb+0x71/0x550 net/core/skbuff.c:198
 alloc_skb include/linux/skbuff.h:1084 [inline]
 __ip6_append_data.isra.0+0x2ac7/0x3890 net/ipv6/ip6_output.c:1588
 ip6_append_data+0x1e7/0x330 net/ipv6/ip6_output.c:1757
 rawv6_sendmsg+0x1483/0x38f0 net/ipv6/raw.c:949
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:814
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x331/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmmsg+0x195/0x480 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2522
 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:00007f035a789c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004fd760 RCX: 000000000045cb29
RDX: 0400000000000107 RSI: 0000000020008440 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000903 R14: 00000000004cbe13 R15: 00007f035a78a6d4


Memory state around the buggy address:
 ffffc900010d7400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900010d7480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900010d7500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                    ^
 ffffc900010d7580: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
 ffffc900010d7600: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
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