================================================================== BUG: KASAN: use-after-free in nr_add_node+0x1d78/0x1fc4 net/netrom/nr_route.c:248 Read of size 2 at addr ffff0000c86f3732 by task syz-executor323/4347 CPU: 1 PID: 4347 Comm: syz-executor323 Not tainted 5.15.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x174/0x1e4 mm/kasan/report.c:451 __asan_report_load2_noabort+0x44/0x50 mm/kasan/report_generic.c:307 nr_add_node+0x1d78/0x1fc4 net/netrom/nr_route.c:248 nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651 nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Allocated by task 4338: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x27c/0x47c mm/slub.c:3247 kmalloc include/linux/slab.h:591 [inline] nr_add_node+0x78c/0x1fc4 net/netrom/nr_route.c:146 nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651 nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Freed by task 4347: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x84 mm/kasan/common.c:46 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kfree+0x178/0x410 mm/slub.c:4559 nr_neigh_put+0x154/0x1f4 include/net/netrom.h:142 nr_add_node+0x1290/0x1fc4 net/netrom/nr_route.c:246 nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651 nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 The buggy address belongs to the object at ffff0000c86f3700 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 50 bytes inside of 128-byte region [ffff0000c86f3700, ffff0000c86f3780) The buggy address belongs to the page: page:000000008f95098a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1086f3 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc00033cd4c0 0000000700000007 ffff0000c0002300 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c86f3600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c86f3680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000c86f3700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000c86f3780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000c86f3800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Unable to handle kernel paging request at virtual address 006f80638000021f 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 [006f80638000021f] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 4347 Comm: syz-executor323 Tainted: G B 5.15.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __hlist_del include/linux/list.h:856 [inline] pc : hlist_del_init include/linux/list.h:884 [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:853 [inline] lr : hlist_del_init include/linux/list.h:884 [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 : ffff800020c976d0 x29: ffff800020c976d0 x28: ffff0000c1631200 x27: 000000000000ffff x26: 0000000000000000 x25: 1fffe0001917d143 x24: ffff0000c8be8a1f x23: dfff800000000000 x22: dfff800000000000 x21: 0000000000000000 x20: ab80031c000010fb x19: ffff0000c86f3700 x18: 0000000000000203 x17: 0000000000000000 x16: ffff8000088d5500 x15: 00000000ffffffff x14: ffff0000c8581b40 x13: 0000000000000001 x12: ffff700004192ebc x11: 1ffff00004192ebc x10: 0000000000000004 x9 : ffff80001b8353d0 x8 : 157000638000021f x7 : 0000000000000000 x6 : ffff800010da1714 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800010da1748 x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000 Call trace: __hlist_del include/linux/list.h:853 [inline] hlist_del_init include/linux/list.h:884 [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+0x17e4/0x1fc4 net/netrom/nr_route.c:249 nr_rt_ioctl+0xe58/0x18c8 net/netrom/nr_route.c:651 nr_ioctl+0x14c/0x4b0 net/netrom/af_netrom.c:1253 sock_do_ioctl+0x134/0x2dc net/socket.c:1140 sock_ioctl+0x4f0/0x8ac net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Code: aa1303e0 97c5cabb d343fe88 f9400275 (38766908) ---[ end trace da4c760d27ea920c ]--- ---------------- Code disassembly (best guess): 0: aa1303e0 mov x0, x19 4: 97c5cabb bl 0xffffffffff172af0 8: d343fe88 lsr x8, x20, #3 c: f9400275 ldr x21, [x19] * 10: 38766908 ldrb w8, [x8, x22] <-- trapping instruction