==================================================================
BUG: KASAN: use-after-free in do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774
Read of size 8 at addr ffff8880689a85b8 by task kswapd1/127

CPU: 0 PID: 127 Comm: kswapd1 Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433
 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
 do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774
 shrink_slab+0x17c/0x6f0 mm/vmscan.c:991
 shrink_node_memcgs mm/vmscan.c:3182 [inline]
 shrink_node+0x8c9/0x1e80 mm/vmscan.c:3304
 kswapd_shrink_node mm/vmscan.c:4086 [inline]
 balance_pgdat+0x8ef/0x1580 mm/vmscan.c:4277
 kswapd+0x79b/0xf80 mm/vmscan.c:4537
 kthread+0x2e4/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Allocated by task 8468:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:437 [inline]
 ____kasan_kmalloc mm/kasan/common.c:516 [inline]
 ____kasan_kmalloc mm/kasan/common.c:475 [inline]
 __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:525
 kasan_kmalloc include/linux/kasan.h:234 [inline]
 __do_kmalloc mm/slab.c:3686 [inline]
 __kmalloc+0x1f9/0x4a0 mm/slab.c:3695
 kmalloc include/linux/slab.h:605 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 ops_init+0xfb/0x470 net/core/net_namespace.c:124
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
 copy_process+0x304d/0x7090 kernel/fork.c:2257
 kernel_clone+0xe7/0xab0 kernel/fork.c:2671
 __do_sys_clone+0xba/0x100 kernel/fork.c:2805
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 8468:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:367 [inline]
 ____kasan_slab_free+0x13d/0x1a0 mm/kasan/common.c:329
 kasan_slab_free include/linux/kasan.h:200 [inline]
 __cache_free mm/slab.c:3418 [inline]
 kfree+0x173/0x390 mm/slab.c:3786
 ops_init+0xcd/0x470 net/core/net_namespace.c:139
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
 copy_process+0x304d/0x7090 kernel/fork.c:2257
 kernel_clone+0xe7/0xab0 kernel/fork.c:2671
 __do_sys_clone+0xba/0x100 kernel/fork.c:2805
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff8880689a8000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1464 bytes inside of
 2048-byte region [ffff8880689a8000, ffff8880689a8800)

The buggy address belongs to the physical page:
page:ffffea0001a26a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x689a8
flags: 0x4fff00000000200(slab|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000200 ffffea0001218dc8 ffffea0001a26a48 ffff888011840800
raw: 0000000000000000 ffff8880689a8000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x40cc0(GFP_KERNEL|__GFP_COMP), pid 8468, tgid 8467 (syz-executor.2), ts 321585958401, free_ts 321187233556
 prep_new_page mm/page_alloc.c:2532 [inline]
 get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283
 __alloc_pages_slowpath.constprop.0+0x34d/0x2300 mm/page_alloc.c:5084
 __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
 __alloc_pages_node include/linux/gfp.h:243 [inline]
 kmem_getpages mm/slab.c:1363 [inline]
 cache_grow_begin+0x75/0x360 mm/slab.c:2569
 fallback_alloc+0x1e2/0x2d0 mm/slab.c:3112
 __do_cache_alloc mm/slab.c:3253 [inline]
 slab_alloc mm/slab.c:3287 [inline]
 __do_kmalloc mm/slab.c:3684 [inline]
 __kmalloc+0x2da/0x4a0 mm/slab.c:3695
 kmalloc include/linux/slab.h:605 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 ops_init+0xfb/0x470 net/core/net_namespace.c:124
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
 copy_process+0x304d/0x7090 kernel/fork.c:2257
 kernel_clone+0xe7/0xab0 kernel/fork.c:2671
 __do_sys_clone+0xba/0x100 kernel/fork.c:2805
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1449 [inline]
 free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499
 free_unref_page_prepare mm/page_alloc.c:3380 [inline]
 free_unref_page+0x19/0x4d0 mm/page_alloc.c:3476
 slab_destroy mm/slab.c:1615 [inline]
 slabs_destroy+0x89/0xc0 mm/slab.c:1635
 __cache_free_alien mm/slab.c:774 [inline]
 cache_free_alien mm/slab.c:790 [inline]
 ___cache_free+0x200/0x3d0 mm/slab.c:3445
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x4f/0x1b0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 ____kasan_kmalloc mm/kasan/common.c:482 [inline]
 __kasan_kmalloc+0xba/0xd0 mm/kasan/common.c:525
 kasan_kmalloc include/linux/kasan.h:234 [inline]
 kmem_cache_alloc_node_trace+0x1f6/0x570 mm/slab.c:3603
 __do_kmalloc_node mm/slab.c:3623 [inline]
 __kmalloc_node+0x38/0x60 mm/slab.c:3631
 kmalloc_array_node include/linux/slab.h:695 [inline]
 kcalloc_node include/linux/slab.h:700 [inline]
 memcg_alloc_slab_cgroups+0xea/0x1e0 mm/memcontrol.c:2830
 account_slab mm/slab.h:630 [inline]
 kmem_getpages mm/slab.c:1371 [inline]
 cache_grow_begin+0x2e3/0x360 mm/slab.c:2569
 fallback_alloc+0x1e2/0x2d0 mm/slab.c:3112
 slab_alloc_node mm/slab.c:3225 [inline]
 kmem_cache_alloc_node_trace+0x176/0x570 mm/slab.c:3601
 __do_kmalloc_node mm/slab.c:3623 [inline]
 __kmalloc_node+0x38/0x60 mm/slab.c:3631
 kmalloc_node include/linux/slab.h:623 [inline]
 kvmalloc_node+0x3f/0x1b0 mm/util.c:613
 kvmalloc include/linux/slab.h:750 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x7f7/0x1280 fs/seq_file.c:210

Memory state around the buggy address:
 ffff8880689a8480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880689a8500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880689a8580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8880689a8600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880689a8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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