================================================================== BUG: KASAN: use-after-free in ax25_release+0x4c8/0x814 net/ax25/af_ax25.c:1061 Read of size 8 at addr ffff0000d0b83008 by task syz.2.347/4960 CPU: 1 PID: 4960 Comm: syz.2.347 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 Call trace: dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 print_address_description+0x78/0x30c mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xec/0x15c mm/kasan/report.c:451 __asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309 ax25_release+0x4c8/0x814 net/ax25/af_ax25.c:1061 __sock_release net/socket.c:649 [inline] sock_close+0xb4/0x1f8 net/socket.c:1336 __fput+0x1c0/0x7f8 fs/file_table.c:311 ____fput+0x20/0x30 fs/file_table.c:339 task_work_run+0x12c/0x1e0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x24b4/0x3128 arch/arm64/kernel/signal.c:949 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Allocated by task 4961: 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 mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb0/0xf0 mm/kasan/common.c:522 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x274/0x3fc mm/slub.c:3247 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:735 [inline] ax25_dev_device_up+0x5c/0x540 net/ax25/ax25_dev.c:55 ax25_device_event+0x504/0x590 net/ax25/af_ax25.c:139 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2049 [inline] call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] __dev_notify_flags+0x250/0x46c net/core/dev.c:-1 dev_change_flags+0xc8/0x154 net/core/dev.c:8929 dev_ifsioc+0x504/0xef4 net/core/dev_ioctl.c:324 dev_ioctl+0x4d0/0xc94 net/core/dev_ioctl.c:587 sock_do_ioctl+0x18c/0x240 net/socket.c:1154 sock_ioctl+0x5c8/0x87c 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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Freed by task 4961: 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+0x128/0x1e8 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kfree+0x170/0x40c mm/slub.c:4559 ax25_dev_put include/net/ax25.h:302 [inline] ax25_dev_device_down+0x468/0x67c net/ax25/ax25_dev.c:-1 ax25_device_event+0x538/0x590 net/ax25/af_ax25.c:144 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2049 [inline] call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] __dev_notify_flags+0x250/0x46c net/core/dev.c:-1 dev_change_flags+0xc8/0x154 net/core/dev.c:8929 dev_ifsioc+0x504/0xef4 net/core/dev_ioctl.c:324 dev_ioctl+0x4d0/0xc94 net/core/dev_ioctl.c:587 sock_do_ioctl+0x18c/0x240 net/socket.c:1154 sock_ioctl+0x5c8/0x87c 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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Last potentially related work creation: kasan_save_stack+0x38/0x68 mm/kasan/common.c:38 kasan_record_aux_stack+0xcc/0x114 mm/kasan/generic.c:348 kvfree_call_rcu+0xb8/0x66c kernel/rcu/tree.c:3600 ip_ma_put+0x118/0x1bc net/ipv4/igmp.c:171 __ip_mc_dec_group+0x52c/0x604 net/ipv4/igmp.c:1697 ip_mc_dec_group include/linux/igmp.h:135 [inline] ip_mc_down+0x2e4/0x3e0 net/ipv4/igmp.c:1752 inetdev_event+0x228/0x127c net/ipv4/devinet.c:1598 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2049 [inline] call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] dev_close_many+0x2cc/0x440 net/core/dev.c:1650 unregister_netdevice_many+0x3d4/0x17d0 net/core/dev.c:11110 __rtnl_newlink net/core/rtnetlink.c:3555 [inline] rtnl_newlink+0x11e8/0x1404 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9d4/0xd04 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2507 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x624/0x8b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x6e8/0x9cc net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x61c/0x920 net/socket.c:2436 ___sys_sendmsg+0x1d0/0x240 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg net/socket.c:2526 [inline] __arm64_sys_sendmsg+0x1a8/0x254 net/socket.c:2526 __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Second to last potentially related work creation: kasan_save_stack+0x38/0x68 mm/kasan/common.c:38 kasan_record_aux_stack+0xcc/0x114 mm/kasan/generic.c:348 insert_work+0x64/0x388 kernel/workqueue.c:1366 __queue_work+0xb30/0x1054 kernel/workqueue.c:1532 queue_work_on+0xc4/0x17c kernel/workqueue.c:1559 queue_work include/linux/workqueue.h:512 [inline] netdevice_queue_work drivers/infiniband/core/roce_gid_mgmt.c:659 [inline] netdevice_event+0x6ac/0x79c drivers/infiniband/core/roce_gid_mgmt.c:802 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2049 [inline] call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] __dev_notify_flags+0x250/0x46c net/core/dev.c:-1 dev_change_flags+0xc8/0x154 net/core/dev.c:8929 do_setlink+0xa20/0x3088 net/core/rtnetlink.c:2779 __rtnl_newlink net/core/rtnetlink.c:3450 [inline] rtnl_newlink+0x10d0/0x1404 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9d4/0xd04 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2507 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x624/0x8b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x6e8/0x9cc net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] __sys_sendto+0x2e8/0x3d8 net/socket.c:2063 __do_sys_sendto net/socket.c:2075 [inline] __se_sys_sendto net/socket.c:2071 [inline] __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2071 __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/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 ffff0000d0b83000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 8 bytes inside of 256-byte region [ffff0000d0b83000, ffff0000d0b83100) The buggy address belongs to the page: page:0000000039bb44d5 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110b82 head:0000000039bb44d5 order:1 compound_mapcount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0002480 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d0b82f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d0b82f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000d0b83000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d0b83080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d0b83100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Unable to handle kernel paging request at virtual address 0060038800001909 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 [0060038800001909] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 4960 Comm: syz.2.347 Tainted: G B 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : __lse_atomic_fetch_sub_release arch/arm64/include/asm/atomic_lse.h:161 [inline] pc : arch_atomic_fetch_sub_release arch/arm64/include/asm/atomic.h:51 [inline] pc : atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:168 [inline] pc : __refcount_dec include/linux/refcount.h:338 [inline] pc : refcount_dec include/linux/refcount.h:359 [inline] pc : dev_put include/linux/netdevice.h:4197 [inline] pc : ax25_release+0x4f4/0x814 net/ax25/af_ax25.c:1061 lr : __lse_atomic_fetch_sub_release arch/arm64/include/asm/atomic_lse.h:161 [inline] lr : arch_atomic_fetch_sub_release arch/arm64/include/asm/atomic.h:51 [inline] lr : atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:168 [inline] lr : __refcount_dec include/linux/refcount.h:338 [inline] lr : refcount_dec include/linux/refcount.h:359 [inline] lr : dev_put include/linux/netdevice.h:4197 [inline] lr : ax25_release+0x4ec/0x814 net/ax25/af_ax25.c:1061 sp : ffff800020a37a00 x29: ffff800020a37a20 x28: dfff800000000000 x27: ffff0000ca1c7080 x26: ffff0000d0063828 x25: 0000000000000002 x24: 00000000ffffffff x23: 9760038800001909 x22: ffff0000d0b83000 x21: ffff0000de7d6018 x20: ffff0000ca1c7000 x19: 1fffe0001a00c705 x18: 1fffe0003421cd96 x17: 1fffe0003421cd96 x16: ffff8000111bc798 x15: ffff8000088e1f08 x14: ffff80000f68abb8 x13: ffff800008202f5c x12: 0000000000ff0100 x11: 0000000000000000 x10: 0000000000000000 x9 : ffff80001045ef30 x8 : ffff0000d8e9d1c0 x7 : 0000000000000000 x6 : ffff8000088e1bfc x5 : ffff0000c2f22610 x4 : 0000000000000000 x3 : ffff80001045ef24 x2 : 0000000000000001 x1 : 0000000000000004 x0 : 0000000000000001 Call trace: __lse_atomic_fetch_sub_release arch/arm64/include/asm/atomic_lse.h:161 [inline] arch_atomic_fetch_sub_release arch/arm64/include/asm/atomic.h:51 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:168 [inline] __refcount_dec include/linux/refcount.h:338 [inline] refcount_dec include/linux/refcount.h:359 [inline] dev_put include/linux/netdevice.h:4197 [inline] ax25_release+0x4f4/0x814 net/ax25/af_ax25.c:1061 __sock_release net/socket.c:649 [inline] sock_close+0xb4/0x1f8 net/socket.c:1336 __fput+0x1c0/0x7f8 fs/file_table.c:311 ____fput+0x20/0x30 fs/file_table.c:339 task_work_run+0x12c/0x1e0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x24b4/0x3128 arch/arm64/kernel/signal.c:949 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Code: d503201f 96006935 52800038 4b1803f8 (b87802f8) ---[ end trace 02636e591ee8a154 ]--- ---------------- Code disassembly (best guess): 0: d503201f nop 4: 96006935 bl 0xfffffffff801a4d8 8: 52800038 mov w24, #0x1 // #1 c: 4b1803f8 neg w24, w24 * 10: b87802f8 ldaddl w24, w24, [x23] <-- trapping instruction