================================================================== 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+0x610/0xf90 net/netrom/nr_route.c:692 Read of size 2 at addr ffff88802a34dc32 by task syz.3.10683/12377 CPU: 0 UID: 0 PID: 12377 Comm: syz.3.10683 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 nr_dec_obs net/netrom/nr_route.c:471 [inline] nr_rt_ioctl+0x610/0xf90 net/netrom/nr_route.c:692 sock_do_ioctl+0x101/0x320 net/socket.c:1254 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f59ced9c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f59cfbd0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f59cf016090 RCX: 00007f59ced9c799 RDX: 0000000000000000 RSI: 00000000000089e2 RDI: 0000000000000006 RBP: 00007f59cee32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f59cf016128 R14: 00007f59cf016090 R15: 00007ffd1d91d278 Allocated by task 741: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5383 kmalloc_noprof include/linux/slab.h:950 [inline] nr_add_node+0x25b/0x2630 net/netrom/nr_route.c:146 nr_rt_ioctl+0xe59/0xf90 net/netrom/nr_route.c:651 sock_do_ioctl+0x101/0x320 net/socket.c:1254 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12377: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2692 [inline] slab_free mm/slub.c:6168 [inline] kfree+0x1c1/0x630 mm/slub.c:6486 nr_dec_obs net/netrom/nr_route.c:469 [inline] nr_rt_ioctl+0x363/0xf90 net/netrom/nr_route.c:692 sock_do_ioctl+0x101/0x320 net/socket.c:1254 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802a34dc00 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 50 bytes inside of freed 64-byte region [ffff88802a34dc00, ffff88802a34dc40) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a34d flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fea88c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800200020 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8765372264, free_ts 8355569138 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3296 [inline] allocate_slab+0x77/0x660 mm/slub.c:3485 new_slab mm/slub.c:3543 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7178 __pcs_replace_empty_main+0x2f9/0x5e0 mm/slub.c:-1 alloc_from_pcs mm/slub.c:4720 [inline] slab_alloc_node mm/slub.c:4854 [inline] __do_kmalloc_node mm/slub.c:5262 [inline] __kmalloc_noprof+0x474/0x760 mm/slub.c:5275 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] kobject_get_path+0xc5/0x2f0 lib/kobject.c:161 kobject_uevent_env+0x2a1/0x9e0 lib/kobject_uevent.c:545 device_add+0x557/0xb70 drivers/base/core.c:3670 usb_add_gadget+0x36f/0x650 drivers/usb/gadget/udc/core.c:1421 usb_add_gadget_udc_release+0x19c/0x1f0 drivers/usb/gadget/udc/core.c:1484 dummy_udc_probe+0x6cc/0x7d0 drivers/usb/gadget/udc/dummy_hcd.c:1099 platform_probe+0xf9/0x190 drivers/base/platform.c:1446 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:661 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803 page last free pid 50 tgid 50 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 vfree+0x25a/0x400 mm/vmalloc.c:3479 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3398 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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: ffff88802a34db00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff88802a34db80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88802a34dc00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802a34dc80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88802a34dd00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ==================================================================