================================================================== BUG: KASAN: use-after-free in ax25_heartbeat_expiry+0x10c/0x128 net/ax25/ax25_timer.c:125 Read of size 4 at addr ffff0000d20f0c50 by task ksoftirqd/0/14 CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.178-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_load4_noabort+0x44/0x50 mm/kasan/report_generic.c:308 ax25_heartbeat_expiry+0x10c/0x128 net/ax25/ax25_timer.c:125 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x384/0xdbc kernel/softirq.c:558 run_ksoftirqd+0x6c/0x29c kernel/softirq.c:925 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 Allocated by task 4161: 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] kzalloc include/linux/slab.h:721 [inline] ax25_dev_device_up+0x5c/0x548 net/ax25/ax25_dev.c:55 ax25_device_event+0x500/0x58c net/ax25/af_ax25.c:139 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391 __dev_notify_flags+0x2ac/0x534 dev_change_flags+0xc8/0x154 net/core/dev.c:8897 dev_ifsioc+0x140/0xfe4 net/core/dev_ioctl.c:324 dev_ioctl+0x4e0/0xd3c net/core/dev_ioctl.c:587 sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154 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 6208: 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 ax25_dev_put include/net/ax25.h:302 [inline] ax25_release+0x57c/0x82c net/ax25/af_ax25.c:1062 __sock_release net/socket.c:649 [inline] sock_close+0xb8/0x1fc net/socket.c:1336 __fput+0x1c4/0x800 fs/file_table.c:280 ____fput+0x20/0x30 fs/file_table.c:308 task_work_run+0x130/0x1e4 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] do_notify_resume+0x262c/0x32b8 arch/arm64/kernel/signal.c:946 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+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609 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 ffff0000d20f0c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 80 bytes inside of 256-byte region [ffff0000d20f0c00, ffff0000d20f0d00) The buggy address belongs to the page: page:00000000f16435fb refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000d20f1a00 pfn:0x1120f0 head:00000000f16435fb order:1 compound_mapcount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc000332ba08 fffffc00034a5b88 ffff0000c0002480 raw: ffff0000d20f1a00 000000000010000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d20f0b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d20f0b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000d20f0c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d20f0c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d20f0d00: 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 0063807e80000322 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 [0063807e80000322] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 14 Comm: ksoftirqd/0 Tainted: G B 5.15.178-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 : ax25_send_control+0x84/0x430 net/ax25/ax25_subr.c:152 lr : ax25_send_control+0x70/0x430 net/ax25/ax25_subr.c:152 sp : ffff80001bd478e0 x29: ffff80001bd478e0 x28: 1fffe0001812a369 x27: dfff800000000000 x26: 1fffe0001ac93905 x25: dfff800000000000 x24: ffff0000d649c828 x23: 000000000000002f x22: 0000000000000001 x21: b32003f400001916 x20: ffff0000d649c800 x19: 0000000000000001 x18: 0000000000000100 x17: 0000000000000000 x16: ffff8000088d55d4 x15: 0000000000000004 x14: ffff0000c0951b40 x13: 0000000000ff0100 x12: ffffffffffffffff x11: 0000000000000100 x10: 0000000000000000 x9 : 0000000000000007 x8 : 1664007e80000322 x7 : 0000000000000000 x6 : ffff8000083bd848 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800010dcac08 x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000 Call trace: ax25_send_control+0x84/0x430 net/ax25/ax25_subr.c:152 ax25_std_t1timer_expiry+0x350/0x540 ax25_t1timer_expiry+0xd8/0x110 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x554/0x718 kernel/time/timer.c:1767 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780 handle_softirqs+0x384/0xdbc kernel/softirq.c:558 run_ksoftirqd+0x6c/0x29c kernel/softirq.c:925 smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 Code: 91035915 d343fea8 12000aa9 11000529 (38f96908) ---[ end trace c3f3c1341a533eb2 ]--- ---------------- Code disassembly (best guess): 0: 91035915 add x21, x8, #0xd6 4: d343fea8 lsr x8, x21, #3 8: 12000aa9 and w9, w21, #0x7 c: 11000529 add w9, w9, #0x1 * 10: 38f96908 ldrsb w8, [x8, x25] <-- trapping instruction