==================================================================
BUG: KASAN: use-after-free in do_shrink_slab+0xbe6/0xce0 mm/vmscan.c:785
Read of size 8 at addr ffff88807cbe95b8 by task syz-executor.3/5312

CPU: 1 PID: 5312 Comm: syz-executor.3 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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:284 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:395
 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495
 do_shrink_slab+0xbe6/0xce0 mm/vmscan.c:785
 shrink_slab+0x17c/0x6e0 mm/vmscan.c:1002
 drop_slab_node mm/vmscan.c:1037 [inline]
 drop_slab+0x104/0x280 mm/vmscan.c:1047
 drop_caches_sysctl_handler+0xf6/0x110 fs/drop_caches.c:66
 proc_sys_call_handler+0x49c/0x6d0 fs/proc/proc_sysctl.c:604
 call_write_iter include/linux/fs.h:2190 [inline]
 do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:729
 do_iter_write+0x182/0x700 fs/read_write.c:855
 vfs_iter_write+0x70/0xa0 fs/read_write.c:896
 iter_file_splice_write+0x741/0xc90 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x110/0x180 fs/splice.c:931
 splice_direct_to_actor+0x331/0x8a0 fs/splice.c:886
 do_splice_direct+0x1a7/0x270 fs/splice.c:974
 do_sendfile+0xb19/0x1270 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1303
 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
RIP: 0033:0x7f963ba8a669
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f963b1ff168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f963bbabf80 RCX: 00007f963ba8a669
RDX: 0000000020002080 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007f963bae5560 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000870 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe6cfa0b9f R14: 00007f963b1ff300 R15: 0000000000022000
 </TASK>

Allocated by task 5283:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa1/0xb0 mm/kasan/common.c:380
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:934 [inline]
 __kmalloc+0x54/0xc0 mm/slab_common.c:947
 kmalloc include/linux/slab.h:564 [inline]
 kzalloc include/linux/slab.h:695 [inline]
 ops_init+0xfb/0x470 net/core/net_namespace.c:125
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:326
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:472
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
 copy_process+0x306e/0x71b0 kernel/fork.c:2259
 kernel_clone+0xe7/0x980 kernel/fork.c:2676
 __do_sys_clone+0xba/0x100 kernel/fork.c:2817
 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 5283:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45
 kasan_set_track+0x21/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2a/0x40 mm/kasan/generic.c:511
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1669 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1695
 slab_free mm/slub.c:3599 [inline]
 __kmem_cache_free+0xab/0x3b0 mm/slub.c:3612
 ops_init+0xcd/0x470 net/core/net_namespace.c:140
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:326
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:472
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
 copy_process+0x306e/0x71b0 kernel/fork.c:2259
 kernel_clone+0xe7/0x980 kernel/fork.c:2676
 __do_sys_clone+0xba/0x100 kernel/fork.c:2817
 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 ffff88807cbe9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1464 bytes inside of
 2048-byte region [ffff88807cbe9000, ffff88807cbe9800)

The buggy address belongs to the physical page:
page:ffffea0001f2fa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffffea00011eba00 pfn:0x7cbe8
head:ffffea0001f2fa00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff888011842000 dead000000080008 0000000000000000
raw: ffffea00011eba00 dead000000000002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7, tgid 7 (kworker/0:0), ts 183873284048, free_ts 183782656636
 prep_new_page mm/page_alloc.c:2538 [inline]
 get_page_from_freelist+0x1092/0x2d20 mm/page_alloc.c:4287
 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5546
 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280
 alloc_slab_page mm/slub.c:1739 [inline]
 allocate_slab+0x213/0x300 mm/slub.c:1884
 new_slab mm/slub.c:1937 [inline]
 ___slab_alloc+0xac1/0x1430 mm/slub.c:3119
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3217
 slab_alloc_node mm/slub.c:3302 [inline]
 __kmem_cache_alloc_node+0x18a/0x3d0 mm/slub.c:3375
 __do_kmalloc_node mm/slab_common.c:933 [inline]
 __kmalloc_node_track_caller+0x45/0xc0 mm/slab_common.c:954
 kmalloc_reserve net/core/skbuff.c:362 [inline]
 __alloc_skb+0xd9/0x2f0 net/core/skbuff.c:434
 alloc_skb include/linux/skbuff.h:1258 [inline]
 alloc_skb_with_frags+0x93/0x6c0 net/core/skbuff.c:6022
 sock_alloc_send_pskb+0x7a3/0x930 net/core/sock.c:2719
 sock_alloc_send_skb include/net/sock.h:1889 [inline]
 mld_newpack.isra.0+0x1b9/0x770 net/ipv6/mcast.c:1748
 add_grhead+0x295/0x340 net/ipv6/mcast.c:1851
 add_grec+0x1082/0x1560 net/ipv6/mcast.c:1989
 mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2236
 mld_send_initial_cr net/ipv6/mcast.c:1232 [inline]
 ipv6_mc_dad_complete+0x1d0/0x690 net/ipv6/mcast.c:2247
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1458 [inline]
 free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508
 free_unref_page_prepare mm/page_alloc.c:3386 [inline]
 free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482
 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2532
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x62/0x80 mm/kasan/common.c:302
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:754 [inline]
 slab_alloc_node mm/slub.c:3336 [inline]
 kmem_cache_alloc_node+0x2ff/0x400 mm/slub.c:3381
 __alloc_skb+0x210/0x2f0 net/core/skbuff.c:422
 alloc_skb include/linux/skbuff.h:1258 [inline]
 alloc_skb_with_frags+0x93/0x6c0 net/core/skbuff.c:6022
 sock_alloc_send_pskb+0x7a3/0x930 net/core/sock.c:2719
 sock_alloc_send_skb include/net/sock.h:1889 [inline]
 mld_newpack.isra.0+0x1b9/0x770 net/ipv6/mcast.c:1748
 add_grhead+0x295/0x340 net/ipv6/mcast.c:1851
 add_grec+0x1082/0x1560 net/ipv6/mcast.c:1989
 mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2236
 mld_send_initial_cr net/ipv6/mcast.c:1232 [inline]
 mld_dad_work+0x1d3/0x690 net/ipv6/mcast.c:2262
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289

Memory state around the buggy address:
 ffff88807cbe9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807cbe9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807cbe9580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88807cbe9600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807cbe9680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================