================================================================== BUG: KASAN: use-after-free in nr_add_node+0x1fc4/0x2120 net/netrom/nr_route.c:248 Read of size 2 at addr ffff0000cc6fc232 by task syz.0.10372/15844 CPU: 0 PID: 15844 Comm: syz.0.10372 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0x100 mm/kasan/report.c:524 __asan_report_load2_noabort+0x2c/0x38 mm/kasan/report_generic.c:349 nr_add_node+0x1fc4/0x2120 net/netrom/nr_route.c:248 nr_rt_ioctl+0x9f8/0xb80 net/netrom/nr_route.c:651 nr_ioctl+0x1c4/0x4e4 net/netrom/af_netrom.c:1254 sock_do_ioctl+0xf8/0x240 net/socket.c:1204 sock_ioctl+0x5c4/0x840 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Allocated by task 15840: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] nr_add_node+0x730/0x2120 net/netrom/nr_route.c:146 nr_rt_ioctl+0x9f8/0xb80 net/netrom/nr_route.c:651 nr_ioctl+0x1c4/0x4e4 net/netrom/af_netrom.c:1254 sock_do_ioctl+0xf8/0x240 net/socket.c:1204 sock_ioctl+0x5c4/0x840 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Freed by task 15844: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_free_info+0x3c/0x60 mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:236 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1ec mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xc0/0x224 mm/slub.c:3700 kfree+0xd0/0x1ac mm/slab_common.c:988 nr_neigh_put+0x144/0x1cc include/net/netrom.h:143 nr_add_node+0x17a4/0x2120 net/netrom/nr_route.c:246 nr_rt_ioctl+0x9f8/0xb80 net/netrom/nr_route.c:651 nr_ioctl+0x1c4/0x4e4 net/netrom/af_netrom.c:1254 sock_do_ioctl+0xf8/0x240 net/socket.c:1204 sock_ioctl+0x5c4/0x840 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000cc6fc200 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 50 bytes inside of 128-byte region [ffff0000cc6fc200, ffff0000cc6fc280) The buggy address belongs to the physical page: page:000000003e598c8f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10c6fc flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc000361ae40 dead000000000003 ffff0000c0002300 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000cc6fc100: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ffff0000cc6fc180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000cc6fc200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000cc6fc280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000cc6fc300: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Unable to handle kernel paging request at virtual address e0d2408bc00007bc KASAN: maybe wild-memory-access in range [0x0696045e00003de0-0x0696045e00003de7] Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [e0d2408bc00007bc] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 15844 Comm: syz.0.10372 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 pstate: 02400005 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : __hlist_del include/linux/list.h:884 [inline] pc : hlist_del_init include/linux/list.h:912 [inline] pc : __nr_remove_neigh net/netrom/nr_route.c:298 [inline] pc : nr_remove_neigh+0x6c/0xec net/netrom/nr_route.c:308 lr : __hlist_del include/linux/list.h:881 [inline] lr : hlist_del_init include/linux/list.h:912 [inline] lr : __nr_remove_neigh net/netrom/nr_route.c:298 [inline] lr : nr_remove_neigh+0x64/0xec net/netrom/nr_route.c:308 sp : ffff800023c97810 x29: ffff800023c97810 x28: 0000000000010001 x27: 1fffe0001b011343 x26: ffff0000d8089a50 x25: 0000000000000000 x24: ffff0000d8089a1f x23: 1fffe0001b011348 x22: dfff800000000000 x21: 0000000000000000 x20: 0696045e00003de4 x19: ffff0000cc6fc200 x18: 0000000000000000 x17: 0000000000000000 x16: ffff8000082e7648 x15: 0000000000000000 x14: 00000000ffffffff x13: 0000000000000001 x12: ffff700004792ee8 x11: 1ffff00004792ee8 x10: 0000000000000004 x9 : ffff80001c327a10 x8 : 00d2c08bc00007bc x7 : 0000000000000001 x6 : ffff800010ac9680 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800010ac96b4 x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000 Call trace: __hlist_del include/linux/list.h:881 [inline] hlist_del_init include/linux/list.h:912 [inline] __nr_remove_neigh net/netrom/nr_route.c:298 [inline] nr_remove_neigh+0x6c/0xec net/netrom/nr_route.c:308 nr_add_node+0x197c/0x2120 net/netrom/nr_route.c:249 nr_rt_ioctl+0x9f8/0xb80 net/netrom/nr_route.c:651 nr_ioctl+0x1c4/0x4e4 net/netrom/af_netrom.c:1254 sock_do_ioctl+0xf8/0x240 net/socket.c:1204 sock_ioctl+0x5c4/0x840 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Code: aa1303e0 97d4996a d343fe88 f9400275 (38766908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: aa1303e0 mov x0, x19 4: 97d4996a bl 0xffffffffff5265ac 8: d343fe88 lsr x8, x20, #3 c: f9400275 ldr x21, [x19] * 10: 38766908 ldrb w8, [x8, x22] <-- trapping instruction