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BUG: KASAN: stack-out-of-bounds in csd_lock_record+0xd2/0xe0 kernel/smp.c:119
Read of size 8 at addr ffffc90004bb7578 by task syz-executor.3/3497

CPU: 1 PID: 3497 Comm: syz-executor.3 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+0xd2/0xe0 kernel/smp.c:119
 flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391
 __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline]
 sysvec_call_function_single+0x4f/0x120 arch/x86/kernel/smp.c:243
 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:credit_entropy_bits.constprop.0+0x12e/0x4b0 drivers/char/random.c:698
Code: fd 4c 8b 25 44 ad 21 06 48 ba 00 00 00 00 00 fc ff df 4c 89 e0 48 c1 e8 03 0f b6 14 10 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 <84> d2 0f 85 43 03 00 00 41 8b 04 24 45 8d 7d fe 41 89 ee 41 89 dc
RSP: 0018:ffffc90000da8c68 EFLAGS: 00000206
RAX: 0000000000000003 RBX: 00000000000062d6 RCX: ffffffff83f836cc
RDX: 0000000000000000 RSI: ffffffff83f836d5 RDI: 0000000000000005
RBP: 0000000000000010 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff88a1f280
R13: 0000000000008000 R14: 1ffff920001b5197 R15: 0000000000000000
 add_timer_randomness+0x1c5/0x240 drivers/char/random.c:1198
 add_disk_randomness+0xbe/0x3f0 drivers/char/random.c:1327
 scsi_end_request+0x718/0x8b0 drivers/scsi/scsi_lib.c:561
 scsi_io_completion+0x1df/0x1310 drivers/scsi/scsi_lib.c:933
 scsi_softirq_done+0x327/0x3c0 drivers/scsi/scsi_lib.c:1459
 blk_done_softirq+0x2db/0x430 block/blk-mq.c:593
 __do_softirq+0x34c/0xa60 kernel/softirq.c:292
 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]
 do_softirq_own_stack+0x111/0x170 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:387 [inline]
 __irq_exit_rcu kernel/softirq.c:417 [inline]
 irq_exit_rcu+0x229/0x270 kernel/softirq.c:429
 common_interrupt+0xa1/0x220 arch/x86/kernel/irq.c:239
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:587
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:ffffc90004b77888 EFLAGS: 00000286
RAX: 1ffffffff1369fe2 RBX: ffff88804c452440 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff87ec83ff
RBP: ffff8880ae735e00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880ae735e00
R13: ffff88808cf00480 R14: ffff8880a6f86f80 R15: 0000000000000402
 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_common+0x45/0xc0 kernel/sched/core.c:4325
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:40
 try_to_wake_up+0xb37/0x1360 kernel/sched/core.c:2661
 wake_up_process kernel/sched/core.c:2725 [inline]
 wake_up_q+0x96/0x100 kernel/sched/core.c:500
 futex_wake+0x3e9/0x490 kernel/futex.c:1642
 do_futex+0x322/0x1a60 kernel/futex.c:3816
 __do_sys_futex kernel/futex.c:3872 [inline]
 __se_sys_futex kernel/futex.c:3840 [inline]
 __x64_sys_futex+0x378/0x4e0 kernel/futex.c:3840
 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:00007f7db0685cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000078bf08 RCX: 000000000045cb29
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 000000000078bf0c
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffd5287d77f R14: 00007f7db06869c0 R15: 000000000078bf0c


Memory state around the buggy address:
 ffffc90004bb7400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004bb7480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004bb7500: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3
                                                                ^
 ffffc90004bb7580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004bb7600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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