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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 ffffc90004ef7830 by task modprobe/22840

CPU: 0 PID: 22840 Comm: modprobe 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:qlink_free mm/kasan/quarantine.c:151 [inline]
RIP: 0010:qlist_free_all+0xfc/0x140 mm/kasan/quarantine.c:167
Code: 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 4c 8b 70 18 e9 40 ff ff ff e8 c3 27 c6 ff 48 83 3d eb 55 01 08 00 74 36 4c 89 ff 57 9d <0f> 1f 44 00 00 4d 85 e4 75 9e 49 c7 45 08 00 00 00 00 49 c7 45 00
RSP: 0000:ffffc900180f7c48 EFLAGS: 00000282
RAX: 0000000000000f29 RBX: ffff88808eb9c000 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000282
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88809ebd4500
R13: ffffc900180f7c80 R14: ffff8880aa000900 R15: 0000000000000282
 quarantine_reduce+0x17e/0x200 mm/kasan/quarantine.c:260
 __kasan_kmalloc.constprop.0+0x9e/0xd0 mm/kasan/common.c:475
 slab_post_alloc_hook mm/slab.h:535 [inline]
 slab_alloc mm/slab.c:3316 [inline]
 kmem_cache_alloc+0x148/0x550 mm/slab.c:3486
 ptlock_alloc+0x1d/0x70 mm/memory.c:5016
 ptlock_init include/linux/mm.h:2151 [inline]
 pgtable_pte_page_ctor include/linux/mm.h:2178 [inline]
 __pte_alloc_one include/asm-generic/pgalloc.h:66 [inline]
 pte_alloc_one+0x68/0x190 arch/x86/mm/pgtable.c:33
 do_fault_around mm/memory.c:3815 [inline]
 do_read_fault mm/memory.c:3855 [inline]
 do_fault mm/memory.c:3988 [inline]
 handle_pte_fault mm/memory.c:4228 [inline]
 __handle_mm_fault mm/memory.c:4360 [inline]
 handle_mm_fault+0x3bd1/0x43f0 mm/memory.c:4397
 do_user_addr_fault+0x5a2/0xd00 arch/x86/mm/fault.c:1295
 handle_page_fault arch/x86/mm/fault.c:1365 [inline]
 exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0033:0x7f6f125fec20
Code: Bad RIP value.
RSP: 002b:00007fffbbd082e0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000


Memory state around the buggy address:
 ffffc90004ef7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004ef7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004ef7800: f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3 00 00 00 00
                                     ^
 ffffc90004ef7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004ef7900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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