================================================================== BUG: KASAN: use-after-free in do_shrink_slab+0xbe6/0xce0 mm/vmscan.c:785 Read of size 8 at addr ffff8880238ca5b8 by task kswapd1/128 CPU: 1 PID: 128 Comm: kswapd1 Not tainted 6.1.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __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+0x175/0x660 mm/vmscan.c:1002 shrink_node_memcgs mm/vmscan.c:6076 [inline] shrink_node+0x93d/0x1f30 mm/vmscan.c:6105 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0x8f5/0x1530 mm/vmscan.c:7084 kswapd+0x707/0xfc0 mm/vmscan.c:7344 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Allocated by task 4208: 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:955 [inline] __kmalloc+0x54/0xc0 mm/slab_common.c:968 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:712 [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+0x306e/0x7190 kernel/fork.c:2256 kernel_clone+0xe7/0x980 kernel/fork.c:2671 __do_sys_clone3+0x1cd/0x2e0 kernel/fork.c:2970 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Freed by task 4208: 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:1724 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] __kmem_cache_free+0xab/0x3b0 mm/slub.c:3674 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+0x306e/0x7190 kernel/fork.c:2256 kernel_clone+0xe7/0x980 kernel/fork.c:2671 __do_sys_clone3+0x1cd/0x2e0 kernel/fork.c:2970 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 The buggy address belongs to the object at ffff8880238ca000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1464 bytes inside of 2048-byte region [ffff8880238ca000, ffff8880238ca800) The buggy address belongs to the physical page: page:ffffea00008e3200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x238c8 head:ffffea00008e3200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842f00 raw: 0000000000000000 0000000000080008 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4208, tgid 4198 (syz-executor.3), ts 191151335632, free_ts 182715966345 prep_new_page mm/page_alloc.c:2538 [inline] get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4287 __alloc_pages_slowpath.constprop.0+0x36b/0x23d0 mm/page_alloc.c:5088 __alloc_pages+0x4a6/0x5a0 mm/page_alloc.c:5567 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280 alloc_slab_page mm/slub.c:1794 [inline] allocate_slab+0x213/0x300 mm/slub.c:1939 new_slab mm/slub.c:1992 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3180 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3279 slab_alloc_node mm/slub.c:3364 [inline] __kmem_cache_alloc_node+0x191/0x3e0 mm/slub.c:3437 __do_kmalloc_node mm/slab_common.c:954 [inline] __kmalloc+0x44/0xc0 mm/slab_common.c:968 kmalloc_array include/linux/slab.h:628 [inline] kcalloc include/linux/slab.h:659 [inline] cache_create_net+0xa3/0x220 net/sunrpc/cache.c:1749 ip_map_cache_create+0x143/0x360 net/sunrpc/svcauth_unix.c:957 sunrpc_init_net+0x139/0x3c0 net/sunrpc/sunrpc_syms.c:42 ops_init+0xaf/0x470 net/core/net_namespace.c:134 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 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:2586 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:737 [inline] slab_alloc_node mm/slub.c:3398 [inline] kmem_cache_alloc_node+0x2fc/0x400 mm/slub.c:3443 __alloc_skb+0x210/0x2f0 net/core/skbuff.c:497 alloc_skb include/linux/skbuff.h:1267 [inline] nlmsg_new include/net/netlink.h:964 [inline] inet_netconf_notify_devconf+0xdd/0x260 net/ipv4/devinet.c:2101 __devinet_sysctl_unregister net/ipv4/devinet.c:2613 [inline] devinet_exit_net+0x1aa/0x280 net/ipv4/devinet.c:2754 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:162 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Memory state around the buggy address: ffff8880238ca480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880238ca500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880238ca580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880238ca600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880238ca680: fb fb 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