================================================================== BUG: KASAN: slab-use-after-free in nr_dec_obs net/netrom/nr_route.c:471 [inline] BUG: KASAN: slab-use-after-free in nr_rt_ioctl+0x2583/0x29b0 net/netrom/nr_route.c:692 Read of size 4 at addr ffff88802b8eb130 by task syz.1.2098/8284 CPU: 0 UID: 0 PID: 8284 Comm: syz.1.2098 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 nr_dec_obs net/netrom/nr_route.c:471 [inline] nr_rt_ioctl+0x2583/0x29b0 net/netrom/nr_route.c:692 nr_ioctl+0x19a/0x2d0 net/netrom/af_netrom.c:1254 sock_do_ioctl+0x115/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6bedb8eec9 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:00007fff288944e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6bedde5fa0 RCX: 00007f6bedb8eec9 RDX: 0000000000000000 RSI: 00000000000089e2 RDI: 0000000000000004 RBP: 00007f6bedc11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6bedde5fa0 R14: 00007f6bedde5fa0 R15: 0000000000000002 Allocated by task 8284: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kmalloc_noprof include/linux/slab.h:957 [inline] nr_add_node+0xe4e/0x2c00 net/netrom/nr_route.c:146 nr_rt_ioctl+0x11b7/0x29b0 net/netrom/nr_route.c:651 nr_ioctl+0x19a/0x2d0 net/netrom/af_netrom.c:1254 sock_do_ioctl+0x115/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 8284: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2515 [inline] slab_free mm/slub.c:6574 [inline] kfree+0x2b8/0x6d0 mm/slub.c:6781 nr_neigh_put include/net/netrom.h:143 [inline] nr_neigh_put include/net/netrom.h:137 [inline] nr_dec_obs net/netrom/nr_route.c:469 [inline] nr_rt_ioctl+0xbed/0x29b0 net/netrom/nr_route.c:692 nr_ioctl+0x19a/0x2d0 net/netrom/af_netrom.c:1254 sock_do_ioctl+0x115/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802b8eb100 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 48 bytes inside of freed 64-byte region [ffff88802b8eb100, ffff88802b8eb140) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b8eb ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b4428c0 ffffea0000ca1f80 dead000000000003 raw: 0000000000000000 0000000000200020 00000000f5000000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 12, tgid 12 (kworker/u32:0), ts 15695089184, free_ts 15695072509 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3031 [inline] allocate_slab mm/slub.c:3204 [inline] new_slab+0x24a/0x360 mm/slub.c:3258 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4628 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4747 __slab_alloc_node mm/slub.c:4823 [inline] slab_alloc_node mm/slub.c:5234 [inline] __do_kmalloc_node mm/slub.c:5603 [inline] __kmalloc_node_noprof+0x4dd/0x8a0 mm/slub.c:5610 kmalloc_node_noprof include/linux/slab.h:987 [inline] __vmalloc_area_node mm/vmalloc.c:3702 [inline] __vmalloc_node_range_noprof+0x3e5/0x1480 mm/vmalloc.c:3897 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:3960 alloc_thread_stack_node kernel/fork.c:311 [inline] dup_task_struct kernel/fork.c:881 [inline] copy_process+0x2c77/0x76a0 kernel/fork.c:2012 kernel_clone+0xfc/0x930 kernel/fork.c:2609 user_mode_thread+0xc8/0x110 kernel/fork.c:2685 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x170 kernel/umh.c:157 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 page last free pid 12 tgid 12 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 __kasan_populate_vmalloc mm/kasan/shadow.c:401 [inline] kasan_populate_vmalloc+0x160/0x2d0 mm/kasan/shadow.c:435 alloc_vmap_area+0x960/0x29e0 mm/vmalloc.c:2098 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3193 __vmalloc_node_range_noprof+0x271/0x1480 mm/vmalloc.c:3857 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:3960 alloc_thread_stack_node kernel/fork.c:311 [inline] dup_task_struct kernel/fork.c:881 [inline] copy_process+0x2c77/0x76a0 kernel/fork.c:2012 kernel_clone+0xfc/0x930 kernel/fork.c:2609 user_mode_thread+0xc8/0x110 kernel/fork.c:2685 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x170 kernel/umh.c:157 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x672/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88802b8eb000: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88802b8eb080: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff88802b8eb100: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802b8eb180: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ffff88802b8eb200: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================