================================================================== BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1787 [inline] BUG: KASAN: use-after-free in exact_lock+0x38/0xd0 block/genhd.c:677 Read of size 8 at addr ffff888100993460 by task syz.0.5587/22605 CPU: 1 PID: 22605 Comm: syz.0.5587 Tainted: G W 5.10.234-syzkaller-00023-g3f5f2283d684 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x179/0x1c0 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+0x38/0xd0 block/genhd.c:677 kobj_lookup+0x294/0x430 drivers/base/map.c:119 get_gendisk+0xf7/0x3d0 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x18c/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_get_by_path+0x25a/0x480 fs/block_dev.c:1690 mount_bdev+0x51/0x370 fs/super.c:1400 vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1057 legacy_get_tree+0xf1/0x190 fs/fs_context.c:593 vfs_get_tree+0x88/0x290 fs/super.c:1572 do_new_mount+0x2ba/0xb30 fs/namespace.c:2917 path_mount+0x56f/0xcb0 fs/namespace.c:3247 do_mount fs/namespace.c:3260 [inline] __do_sys_mount fs/namespace.c:3468 [inline] __se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3445 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3445 do_syscall_64+0x34/0x70 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f21e70b0169 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:00007f21e571a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f21e72c8fa0 RCX: 00007f21e70b0169 RDX: 0000400000000340 RSI: 00004000000000c0 RDI: 00004000000001c0 RBP: 00007f21e71312a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f21e72c8fa0 R15: 00007ffc8e41a2e8 Allocated by task 21792: 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+0xdb/0x110 mm/kasan/common.c:509 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x1aa/0x330 mm/slub.c:4033 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x82/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:822 [inline] xt_alloc_table_info+0x42/0xb0 net/netfilter/x_tables.c:1172 do_replace net/ipv6/netfilter/ip6_tables.c:1145 [inline] do_ip6t_set_ctl+0xb1b/0x1220 net/ipv6/netfilter/ip6_tables.c:1646 nf_setsockopt+0x274/0x2a0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x2789/0x3ea0 net/ipv6/ipv6_sockglue.c:1014 tcp_setsockopt+0x22d/0x3660 net/ipv4/tcp.c:3499 sock_common_setsockopt+0xa2/0xc0 net/core/sock.c:3318 __sys_setsockopt+0x502/0x870 net/socket.c:2146 __do_sys_setsockopt net/socket.c:2157 [inline] __se_sys_setsockopt net/socket.c:2154 [inline] __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2154 do_syscall_64+0x34/0x70 entry_SYSCALL_64_after_hwframe+0x61/0xcb Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x135/0x11f0 kernel/rcu/tree.c:3050 netlink_release+0x13ad/0x17d0 net/netlink/af_netlink.c:796 __sock_release net/socket.c:597 [inline] sock_close+0xdf/0x270 net/socket.c:1286 __fput+0x33d/0x7b0 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x129/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274 do_syscall_64+0x40/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb Second to last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x135/0x11f0 kernel/rcu/tree.c:3050 netlink_release+0x13ad/0x17d0 net/netlink/af_netlink.c:796 __sock_release net/socket.c:597 [inline] sock_release+0x7e/0x140 net/socket.c:625 netlink_kernel_release+0x4d/0x60 net/netlink/af_netlink.c:2089 uevent_net_exit+0xc2/0x200 lib/kobject_uevent.c:814 ops_exit_list net/core/net_namespace.c:185 [inline] cleanup_net+0x66c/0xcb0 net/core/net_namespace.c:609 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/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 ffff888100993000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1120 bytes inside of 2048-byte region [ffff888100993000, ffff888100993800) The buggy address belongs to the page: page:ffffea0004026400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888100993000 pfn:0x100990 head:ffffea0004026400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea00046e6608 ffffea0004960a08 ffff888100042d80 raw: ffff888100993000 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2014977102, 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+0x166/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348 allocate_slab mm/slub.c:1808 [inline] new_slab+0x80/0x400 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x302/0x4b0 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+0x1bd/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] __alloc_disk_node+0x76/0x570 block/genhd.c:1727 brd_alloc+0x146/0x400 drivers/block/brd.c:394 brd_init+0x125/0x474 drivers/block/brd.c:517 do_one_initcall+0x189/0x620 init/main.c:1197 do_initcall_level+0x186/0x304 init/main.c:1270 do_initcalls+0x4e/0x8e init/main.c:1286 do_basic_setup+0x88/0x91 init/main.c:1306 kernel_init_freeable+0x2be/0x3f5 init/main.c:1510 kernel_init+0x11/0x280 init/main.c:1397 page_owner free stack trace missing Memory state around the buggy address: ffff888100993300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888100993380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888100993400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888100993480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888100993500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================