================================================================== BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1787 [inline] BUG: KASAN: use-after-free in exact_lock+0x38/0xc0 block/genhd.c:677 Read of size 8 at addr ffff8881009ec460 by task syz.1.4681/17876 CPU: 1 PID: 17876 Comm: syz.1.4681 Tainted: G W 5.10.236-syzkaller-00012-gab07aeb2c93d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309 get_disk_and_module block/genhd.c:1787 [inline] exact_lock+0x38/0xc0 block/genhd.c:677 kobj_lookup+0x298/0x430 drivers/base/map.c:119 get_gendisk+0xe9/0x340 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_open+0x208/0x430 fs/block_dev.c:1770 do_dentry_open+0x793/0x1090 fs/open.c:819 vfs_open+0x73/0x80 fs/open.c:942 do_open fs/namei.c:3391 [inline] path_openat+0x27ad/0x3160 fs/namei.c:3509 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217 do_sys_open fs/open.c:1233 [inline] __do_sys_creat fs/open.c:1309 [inline] __se_sys_creat fs/open.c:1303 [inline] __x64_sys_creat+0x8e/0xb0 fs/open.c:1303 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f86a73b2969 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f86a5a1b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f86a75d9fa0 RCX: 00007f86a73b2969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0 RBP: 00007f86a7434ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f86a75d9fa0 R15: 00007fff33f6cb98 Allocated by task 16190: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x1a7/0x330 mm/slub.c:4033 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:664 [inline] __register_sysctl_table+0xeb/0x1250 fs/proc/proc_sysctl.c:1319 register_net_sysctl+0x2c/0x40 net/sysctl_net.c:121 __addrconf_sysctl_register+0x26e/0x3d0 net/ipv6/addrconf.c:7049 addrconf_sysctl_register+0x147/0x1a0 net/ipv6/addrconf.c:7096 ipv6_add_dev+0xbaf/0x10a0 net/ipv6/addrconf.c:448 addrconf_notify+0x582/0xe90 net/ipv6/addrconf.c:3567 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2054 [inline] call_netdevice_notifiers_extack net/core/dev.c:2066 [inline] call_netdevice_notifiers+0x111/0x190 net/core/dev.c:2080 register_netdevice+0x1043/0x13c0 net/core/dev.c:10086 register_netdev+0x3e/0x50 net/core/dev.c:10179 vti6_init_net+0x2c0/0x380 net/ipv6/ip6_vti.c:1160 ops_init+0x1ba/0x4a0 net/core/net_namespace.c:144 setup_net+0x36d/0xb50 net/core/net_namespace.c:345 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3080 __do_sys_unshare kernel/fork.c:3148 [inline] __se_sys_unshare kernel/fork.c:3146 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3146 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 kvfree_call_rcu+0x10c/0x620 kernel/rcu/tree.c:3535 drop_sysctl_table+0x2ef/0x410 fs/proc/proc_sysctl.c:1680 unregister_sysctl_table+0x75/0x120 fs/proc/proc_sysctl.c:1718 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:127 __addrconf_sysctl_unregister net/ipv6/addrconf.c:7078 [inline] addrconf_sysctl_unregister net/ipv6/addrconf.c:7106 [inline] addrconf_ifdown+0x1507/0x1800 net/ipv6/addrconf.c:3936 addrconf_notify+0x3bd/0xe90 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2054 [inline] call_netdevice_notifiers_extack net/core/dev.c:2066 [inline] call_netdevice_notifiers net/core/dev.c:2080 [inline] unregister_netdevice_many+0xf8b/0x1980 net/core/dev.c:10766 vti6_exit_batch_net+0x26a/0x2b0 net/ipv6/ip6_vti.c:1186 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff8881009ec000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1120 bytes inside of 2048-byte region [ffff8881009ec000, ffff8881009ec800) The buggy address belongs to the page: page:ffffea0004027a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8881009e9000 pfn:0x1009e8 head:ffffea0004027a00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea0004a02c08 ffffea0004d19e08 ffff888100042d80 raw: ffff8881009e9000 0000000000080006 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 1, ts 2069216483, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5349 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972 kmem_cache_alloc_node_trace include/linux/slab.h:440 [inline] kmalloc_node include/linux/slab.h:570 [inline] kzalloc_node include/linux/slab.h:675 [inline] bdi_alloc+0x4e/0x110 mm/backing-dev.c:746 blk_alloc_queue+0x103/0x610 block/blk-core.c:535 brd_alloc+0xfe/0x3e0 drivers/block/brd.c:383 brd_init+0x125/0x468 drivers/block/brd.c:517 do_one_initcall+0x187/0x510 init/main.c:1197 do_initcall_level+0x16f/0x2cf init/main.c:1270 do_initcalls+0x50/0x92 init/main.c:1286 do_basic_setup+0x88/0x8f init/main.c:1306 kernel_init_freeable+0x287/0x3be init/main.c:1510 page_owner free stack trace missing Memory state around the buggy address: ffff8881009ec300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881009ec380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881009ec400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881009ec480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881009ec500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================