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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 ffffc900049c7978 by task systemd-udevd/3877

CPU: 1 PID: 3877 Comm: systemd-udevd 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
 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:lock_acquire+0x270/0xad0 kernel/locking/lockdep.c:4962
Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 f8 06 00 00 48 83 3d 6d c1 5a 08 00 0f 84 a6 05 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 10 48 c7
RSP: 0018:ffffc90001277980 EFLAGS: 00000282
RAX: 1ffffffff1369fe0 RBX: ffff8880a479e1c0 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: e668264dc84383e6 RDI: 0000000000000282
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c5a7a27
R10: fffffbfff18b4f44 R11: 0000000000000000 R12: 0000000000000002
R13: ffffffff89bc3040 R14: 0000000000000000 R15: ffff8880a479e1c0
 rcu_lock_acquire include/linux/rcupdate.h:241 [inline]
 rcu_read_lock include/linux/rcupdate.h:634 [inline]
 dput+0x74/0xbc0 fs/dcache.c:864
 path_put fs/namei.c:496 [inline]
 terminate_walk+0x3e8/0x570 fs/namei.c:597
 path_lookupat+0x25a/0x830 fs/namei.c:2350
 filename_lookup+0x19f/0x560 fs/namei.c:2366
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x14e/0x390 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3161 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f51bb4ed335
Code: Bad RIP value.
RSP: 002b:00007ffd57e38fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000006
RAX: ffffffffffffffda RBX: 000055cce00b41d0 RCX: 00007f51bb4ed335
RDX: 00007ffd57e38ff0 RSI: 00007ffd57e38ff0 RDI: 000055cce00b31d0
RBP: 00007ffd57e390b0 R08: 00007f51bb7ac178 R09: 0000000000001010
R10: 0000000000000020 R11: 0000000000000246 R12: 000055cce00b31d0
R13: 000055cce00b31d8 R14: 000055cce00b3195 R15: 000055cce00b3198


Memory state around the buggy address:
 ffffc900049c7800: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
 ffffc900049c7880: 00 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 00
>ffffc900049c7900: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
                                                                ^
 ffffc900049c7980: 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
 ffffc900049c7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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