================================================================== ================================================================== BUG: KASAN: use-after-free in nexthop_flush_dev+0x20b/0x230 net/ipv4/nexthop.c:2381 Read of size 8 at addr ffff88804f94f058 by task syz-executor.4/3779 CPU: 1 PID: 3779 Comm: syz-executor.4 Not tainted 5.19.0-rc2-syzkaller-00148-g12378a5a75e3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 nexthop_flush_dev+0x20b/0x230 net/ipv4/nexthop.c:2381 nh_netdev_event+0x2c6/0x370 net/ipv4/nexthop.c:3574 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] call_netdevice_notifiers net/core/dev.c:1997 [inline] netdev_wait_allrefs_any net/core/dev.c:10227 [inline] netdev_run_todo+0xbc0/0x10f0 net/core/dev.c:10341 tun_detach drivers/net/tun.c:695 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3444 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xaff/0x2a00 kernel/exit.c:795 do_group_exit+0xd2/0x2f0 kernel/exit.c:925 __do_sys_exit_group kernel/exit.c:936 [inline] __se_sys_exit_group kernel/exit.c:934 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934 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+0x46/0xb0 RIP: 0033:0x7f84c4889109 Code: Unable to access opcode bytes at RIP 0x7f84c48890df. RSP: 002b:00007ffceac451b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffceac45360 RCX: 00007f84c4889109 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffceac45360 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f84c48e302e R13: 000000000000001c R14: 0000000000000003 R15: 00007ffceac453a0 Allocated by task 3779: 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:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] nexthop_net_init+0x71/0x140 net/ipv4/nexthop.c:3753 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 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3165 __do_sys_unshare kernel/fork.c:3236 [inline] __se_sys_unshare kernel/fork.c:3234 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3234 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+0x46/0xb0 Freed by task 5299: 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:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1727 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753 slab_free mm/slub.c:3507 [inline] kfree+0xd6/0x4d0 mm/slub.c:4555 nexthop_net_exit_batch+0x245/0x2d0 net/ipv4/nexthop.c:3743 ops_exit_list+0x125/0x170 net/core/net_namespace.c:167 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 The buggy address belongs to the object at ffff88804f94f000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 88 bytes inside of 2048-byte region [ffff88804f94f000, ffff88804f94f800) The buggy address belongs to the physical page: page:ffffea00013e5200 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804f948000 pfn:0x4f948 head:ffffea00013e5200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea00015d1e08 ffffea0001d6f208 ffff888011842000 raw: ffff88804f948000 0000000000080007 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 3779, tgid 3779 (syz-executor.4), ts 133307762081, free_ts 130910027841 prep_new_page mm/page_alloc.c:2456 [inline] get_page_from_freelist+0x1290/0x3b70 mm/page_alloc.c:4198 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5426 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1797 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1942 new_slab mm/slub.c:2002 [inline] ___slab_alloc+0x985/0xd90 mm/slub.c:3002 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3089 slab_alloc_node mm/slub.c:3180 [inline] __kmalloc_node_track_caller+0x2cb/0x360 mm/slub.c:4950 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0xde/0x340 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1426 [inline] nlmsg_new include/net/netlink.h:953 [inline] rtmsg_ifinfo_build_skb+0x72/0x1a0 net/core/rtnetlink.c:3904 rtmsg_ifinfo_event net/core/rtnetlink.c:3940 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3931 [inline] rtnetlink_event+0x123/0x1d0 net/core/rtnetlink.c:6140 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] call_netdevice_notifiers net/core/dev.c:1997 [inline] dev_set_mac_address+0x2d3/0x3d0 net/core/dev.c:8793 dev_set_mac_address_user+0x2d/0x50 net/core/dev.c:8807 do_setlink+0x18c4/0x3bb0 net/core/rtnetlink.c:2735 __rtnl_newlink+0xd6a/0x17e0 net/core/rtnetlink.c:3546 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1371 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1421 free_unref_page_prepare mm/page_alloc.c:3343 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3438 __vunmap+0x85d/0xd30 mm/vmalloc.c:2665 __vfree+0x3c/0xd0 mm/vmalloc.c:2713 vfree+0x5a/0x90 mm/vmalloc.c:2744 kcov_put kernel/kcov.c:421 [inline] kcov_put+0x26/0x40 kernel/kcov.c:417 kcov_close+0xc/0x10 kernel/kcov.c:517 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xaff/0x2a00 kernel/exit.c:795 do_group_exit+0xd2/0x2f0 kernel/exit.c:925 __do_sys_exit_group kernel/exit.c:936 [inline] __se_sys_exit_group kernel/exit.c:934 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934 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+0x46/0xb0 Memory state around the buggy address: ffff88804f94ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804f94ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88804f94f000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804f94f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804f94f100: fb fb fb fb fb fb fb fb 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