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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 ffffc9000808f970 by task syz-executor.1/28142

CPU: 0 PID: 28142 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x4b/0x80 kernel/locking/spinlock.c:199
Code: c0 10 ff b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d ee 7a c8 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 db 01 63 f9 65 8b 05 44 7a 15 78 85 c0 74 02 5d
RSP: 0018:ffffc90017b46eb8 EFLAGS: 00000286
RAX: 1ffffffff1369fe2 RBX: ffff8880905183c0 RCX: 0000000000000006
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff87ec83ff
RBP: ffff8880ae635e00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880ae635e00
R13: ffff8880542d04c0 R14: 0000000000000000 R15: 0000000000000001
 finish_lock_switch kernel/sched/core.c:3184 [inline]
 finish_task_switch+0x147/0x750 kernel/sched/core.c:3284
 context_switch kernel/sched/core.c:3448 [inline]
 __schedule+0x8bc/0x1e80 kernel/sched/core.c:4169
 preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:4427
 idtentry_exit_cond_resched arch/x86/entry/common.c:645 [inline]
 idtentry_exit_cond_rcu+0xc0/0xf0 arch/x86/entry/common.c:692
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596
RIP: 0010:batadv_hardif_recalc_extra_skbroom+0x100/0x420 net/batman-adv/hard-interface.c:537
Code: 0f 85 ca 02 00 00 48 8b 1b 48 81 fb 60 7a 50 8d 0f 84 1f 01 00 00 e8 0f cc a6 f9 48 8d 7b 10 48 89 f8 48 c1 e8 03 0f b6 04 28 <84> c0 74 06 0f 8e a9 02 00 00 44 0f b6 7b 10 31 ff 44 89 fe e8 27
RSP: 0018:ffffc90017b470e0 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff88809b997800 RCX: ffffc9000470c000
RDX: 0000000000040000 RSI: ffffffff87cd3af1 RDI: ffff88809b997810
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8c5a7a27
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000098
R13: ffff888061134000 R14: 0000000000000000 R15: 0000000000000002
 batadv_hardif_enable_interface+0x92b/0xb10 net/batman-adv/hard-interface.c:798
 batadv_softif_slave_add+0x92/0x150 net/batman-adv/soft-interface.c:892
 do_set_master+0x1c8/0x220 net/core/rtnetlink.c:2476
 __rtnl_newlink+0x132f/0x1730 net/core/rtnetlink.c:3366
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3397
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5460
 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 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:00007f0939891c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000502760 RCX: 000000000045cb29
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a43 R14: 00000000004cd2a1 R15: 00007f09398926d4


Memory state around the buggy address:
 ffffc9000808f800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000808f880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000808f900: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
                                                                ^
 ffffc9000808f980: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000808fa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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