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BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in queued_spin_trylock include/asm-generic/qspinlock.h:69 [inline]
BUG: KASAN: use-after-free in do_raw_spin_trylock+0x6a/0x180 kernel/locking/spinlock_debug.c:119
Read of size 4 at addr ffff88808a28ccd4 by task syz-executor.0/17585

CPU: 0 PID: 17585 Comm: syz-executor.0 Not tainted 5.0.0+ #105
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_read+0x11/0x20 mm/kasan/common.c:102
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 queued_spin_trylock include/asm-generic/qspinlock.h:69 [inline]
 do_raw_spin_trylock+0x6a/0x180 kernel/locking/spinlock_debug.c:119
 __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline]
 _raw_spin_trylock+0x1c/0x80 kernel/locking/spinlock.c:128
 spin_trylock include/linux/spinlock.h:339 [inline]
 icmp_xmit_lock net/ipv4/icmp.c:219 [inline]
 __icmp_send+0x553/0x1400 net/ipv4/icmp.c:666
 icmp_send include/net/icmp.h:47 [inline]
 ipv4_link_failure+0x31/0x210 net/ipv4/route.c:1190
 dst_link_failure include/net/dst.h:416 [inline]
 arp_error_report+0xd1/0x1c0 net/ipv4/arp.c:297
 neigh_invalidate+0x24b/0x570 net/core/neighbour.c:995
 neigh_timer_handler+0xc35/0xf30 net/core/neighbour.c:1081
 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325
 expire_timers kernel/time/timer.c:1362 [inline]
 __run_timers kernel/time/timer.c:1681 [inline]
 __run_timers kernel/time/timer.c:1649 [inline]
 run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694
 __do_softirq+0x266/0x95a kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:filename_mountpoint+0x25d/0x3c0 fs/namei.c:2722
Code: 14 02 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 1c 01 00 00 45 8b 24 24 31 ff 44 89 e6 e8 58 ea ba ff 45 85 e4 74 62 <e8> ce e8 ba ff e8 49 2a fe ff 4c 89 f7 e8 81 f2 ff ff e8 bc e8 ba
RSP: 0018:ffff8880a857fc30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 1ffff110150aff88 RCX: ffffffff81b57ad4
RDX: 1ffff1100bd8e54c RSI: ffffffff81b57ae2 RDI: ffff88805ec72a60
RBP: ffff8880a857fdc8 R08: ffff88805ec72300 R09: 0000000000000001
R10: 000000000000001c R11: ffff8880ae82de3b R12: 0000000000000000
R13: 0000000000000000 R14: ffff888097790e00 R15: ffff8880a857fe68
 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2745
 ksys_umount+0x167/0xf00 fs/namespace.c:1687
 __do_sys_umount fs/namespace.c:1713 [inline]
 __se_sys_umount fs/namespace.c:1711 [inline]
 __x64_sys_umount+0x54/0x80 fs/namespace.c:1711
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ac57
Code: 44 00 00 b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4d 8e fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d 8e fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe6359ff08 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045ac57
RDX: 0000000000402ea0 RSI: 0000000000000002 RDI: 00007ffe6359ffb0
RBP: 00000000000019e0 R08: 0000000000000000 R09: 000000000000000d
R10: 0000000000000006 R11: 0000000000000202 R12: 00007ffe635a1040
R13: 0000000000bfa940 R14: 0000000000000000 R15: 00007ffe635a1040

Allocated by task 12478:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505
 slab_post_alloc_hook mm/slab.h:436 [inline]
 slab_alloc mm/slab.c:3392 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3554
 getname_flags fs/namei.c:138 [inline]
 getname_flags+0xd6/0x5b0 fs/namei.c:128
 getname+0x1a/0x20 fs/namei.c:209
 do_sys_open+0x2c9/0x5d0 fs/open.c:1057
 __do_sys_open fs/open.c:1081 [inline]
 __se_sys_open fs/open.c:1076 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1076
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 12478:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3764
 putname+0xef/0x130 fs/namei.c:259
 do_sys_open+0x318/0x5d0 fs/open.c:1072
 __do_sys_open fs/open.c:1081 [inline]
 __se_sys_open fs/open.c:1076 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1076
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808a28c780
 which belongs to the cache names_cache of size 4096
The buggy address is located 1364 bytes inside of
 4096-byte region [ffff88808a28c780, ffff88808a28d780)
The buggy address belongs to the page:
page:ffffea000228a300 count:1 mapcount:0 mapping:ffff88812c2d8dc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00025c8908 ffffea0001840a08 ffff88812c2d8dc0
raw: 0000000000000000 ffff88808a28c780 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808a28cb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808a28cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808a28cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88808a28cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808a28cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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