================================================================== BUG: KASAN: use-after-free in ext4_xattr_delete_inode+0xc1f/0xc30 fs/ext4/xattr.c:2917 Read of size 4 at addr ffff8881d8ae7000 by task syz-executor/547 CPU: 1 PID: 547 Comm: syz-executor Not tainted 5.4.283-syzkaller-04984-ge6ac8beecb16 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 ext4_xattr_delete_inode+0xc1f/0xc30 fs/ext4/xattr.c:2917 ext4_evict_inode+0x1378/0x1ac0 fs/ext4/inode.c:318 evict+0x4ea/0x960 fs/inode.c:610 d_delete_notify include/linux/fsnotify.h:230 [inline] vfs_rmdir+0x24b/0x3c0 fs/namei.c:4040 do_rmdir+0x2c1/0x580 fs/namei.c:4088 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f3115ff71a7 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe7dc35518 EFLAGS: 00000207 ORIG_RAX: 0000000000000107 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007f3115ff71a7 RDX: 0000000000000200 RSI: 00007ffe7dc366c0 RDI: 00000000ffffff9c RBP: 00007f311606564a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffe7dc366c0 R13: 00007f311606564a R14: 000000000000d288 R15: 00007ffe7dc388a0 Allocated by task 427: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] __alloc_skb+0x7a/0x4d0 net/core/skbuff.c:198 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet6_netconf_notify_devconf+0xc9/0x180 net/ipv6/addrconf.c:573 __addrconf_sysctl_register+0x380/0x3e0 net/ipv6/addrconf.c:6974 addrconf_sysctl_register+0x128/0x180 net/ipv6/addrconf.c:7011 ipv6_add_dev+0xb34/0x10a0 net/ipv6/addrconf.c:444 addrconf_notify+0x59b/0xe50 net/ipv6/addrconf.c:3556 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] register_netdevice+0xeef/0x12a0 net/core/dev.c:9221 register_netdev+0x37/0x50 net/core/dev.c:9319 loopback_net_init+0x6f/0x140 drivers/net/loopback.c:214 ops_init+0x1d4/0x4a0 net/core/net_namespace.c:141 setup_net+0x214/0x990 net/core/net_namespace.c:348 copy_net_ns+0x30d/0x510 net/core/net_namespace.c:489 create_new_namespaces+0x47a/0x570 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0x119/0x170 kernel/nsproxy.c:202 ksys_unshare+0x544/0x990 kernel/fork.c:2908 __do_sys_unshare kernel/fork.c:2976 [inline] __se_sys_unshare kernel/fork.c:2974 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:2974 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 427: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096 netlink_broadcast_filtered+0x115f/0x1280 net/netlink/af_netlink.c:1531 netlink_broadcast net/netlink/af_netlink.c:1553 [inline] nlmsg_multicast include/net/netlink.h:968 [inline] nlmsg_notify+0xf7/0x1b0 net/netlink/af_netlink.c:2524 __addrconf_sysctl_register+0x380/0x3e0 net/ipv6/addrconf.c:6974 addrconf_sysctl_register+0x128/0x180 net/ipv6/addrconf.c:7011 ipv6_add_dev+0xb34/0x10a0 net/ipv6/addrconf.c:444 addrconf_notify+0x59b/0xe50 net/ipv6/addrconf.c:3556 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] register_netdevice+0xeef/0x12a0 net/core/dev.c:9221 register_netdev+0x37/0x50 net/core/dev.c:9319 loopback_net_init+0x6f/0x140 drivers/net/loopback.c:214 ops_init+0x1d4/0x4a0 net/core/net_namespace.c:141 setup_net+0x214/0x990 net/core/net_namespace.c:348 copy_net_ns+0x30d/0x510 net/core/net_namespace.c:489 create_new_namespaces+0x47a/0x570 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0x119/0x170 kernel/nsproxy.c:202 ksys_unshare+0x544/0x990 kernel/fork.c:2908 __do_sys_unshare kernel/fork.c:2976 [inline] __se_sys_unshare kernel/fork.c:2974 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:2974 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 The buggy address belongs to the object at ffff8881d8ae7000 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 0 bytes inside of 240-byte region [ffff8881d8ae7000, ffff8881d8ae70f0) The buggy address belongs to the page: page:ffffea000762b9c0 refcount:1 mapcount:0 mapping:ffff8881f1ccc500 index:0x0 flags: 0x8000000000000200(slab) raw: 8000000000000200 dead000000000100 dead000000000122 ffff8881f1ccc500 raw: 0000000000000000 00000000000c000c 00000001ffffffff 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x109/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] __alloc_skb+0x7a/0x4d0 net/core/skbuff.c:198 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet_netconf_notify_devconf+0x156/0x210 net/ipv4/devinet.c:2107 __devinet_sysctl_register+0x232/0x2a0 net/ipv4/devinet.c:2594 devinet_sysctl_register+0x13a/0x1a0 net/ipv4/devinet.c:2628 inetdev_init+0x24e/0x450 net/ipv4/devinet.c:276 inetdev_event+0x205/0x1040 net/ipv4/devinet.c:1531 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] register_netdevice+0xeef/0x12a0 net/core/dev.c:9221 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] free_pcp_prepare mm/page_alloc.c:1233 [inline] free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085 free_unref_page mm/page_alloc.c:3134 [inline] free_the_page mm/page_alloc.c:4953 [inline] __free_pages+0xaf/0x140 mm/page_alloc.c:4961 __free_slab+0x221/0x2e0 mm/slub.c:1774 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 run_ksoftirqd+0x1f/0x30 kernel/softirq.c:603 smpboot_thread_fn+0x545/0x930 kernel/smpboot.c:165 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Memory state around the buggy address: ffff8881d8ae6f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881d8ae6f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881d8ae7000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d8ae7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff8881d8ae7100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================