================================================================== BUG: KASAN: use-after-free in dvb_device_open+0xd4/0x388 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff0000cc86ac18 by task syz.2.1323/9096 CPU: 1 PID: 9096 Comm: syz.2.1323 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: dump_backtrace+0x1c0/0x1ec 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+0xf4/0x15c 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+0xa8/0xfc mm/kasan/report.c:524 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351 dvb_device_open+0xd4/0x388 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x3d4/0x518 fs/char_dev.c:414 do_dentry_open+0x72c/0xf98 fs/open.c:882 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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 8915: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc+0xec/0x178 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] kzalloc include/linux/slab.h:699 [inline] new_dir fs/proc/proc_sysctl.c:973 [inline] get_subdir fs/proc/proc_sysctl.c:1017 [inline] __register_sysctl_table+0x82c/0xc54 fs/proc/proc_sysctl.c:1379 register_net_sysctl+0x308/0x350 net/sysctl_net.c:168 __addrconf_sysctl_register+0x218/0x370 net/ipv6/addrconf.c:7150 addrconf_init_net+0x41c/0x638 net/ipv6/addrconf.c:7273 ops_init+0x2b0/0x53c net/core/net_namespace.c:138 setup_net+0x474/0xb34 net/core/net_namespace.c:336 copy_net_ns+0x2b8/0x578 net/core/net_namespace.c:508 create_new_namespaces+0x318/0x5ec kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x108/0x158 kernel/nsproxy.c:226 ksys_unshare+0x3e0/0x6dc kernel/fork.c:3282 __do_sys_unshare kernel/fork.c:3353 [inline] __se_sys_unshare kernel/fork.c:3351 [inline] __arm64_sys_unshare+0x3c/0x50 kernel/fork.c:3351 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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 4408: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] kmem_cache_free_bulk+0x33c/0x3d0 mm/slub.c:3805 kfree_bulk include/linux/slab.h:475 [inline] kfree_rcu_work+0x288/0x6bc kernel/rcu/tree.c:3091 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:46 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 kvfree_call_rcu+0xb4/0x6e8 kernel/rcu/tree.c:3405 drop_sysctl_table+0x278/0x3c0 fs/proc/proc_sysctl.c:1731 drop_sysctl_table+0x298/0x3c0 fs/proc/proc_sysctl.c:1734 unregister_sysctl_table+0x90/0x130 fs/proc/proc_sysctl.c:1769 unregister_net_sysctl_table+0x20/0x30 net/sysctl_net.c:174 __addrconf_sysctl_unregister net/ipv6/addrconf.c:7179 [inline] addrconf_exit_net+0x90/0x28c net/ipv6/addrconf.c:7300 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x5d0/0xa84 net/core/net_namespace.c:640 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Second to last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:46 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 kvfree_call_rcu+0xb4/0x6e8 kernel/rcu/tree.c:3405 drop_sysctl_table+0x278/0x3c0 fs/proc/proc_sysctl.c:1731 drop_sysctl_table+0x298/0x3c0 fs/proc/proc_sysctl.c:1734 unregister_sysctl_table+0x90/0x130 fs/proc/proc_sysctl.c:1769 unregister_net_sysctl_table+0x20/0x30 net/sysctl_net.c:174 mpls_dev_sysctl_unregister+0x8c/0xc4 net/mpls/af_mpls.c:1445 mpls_dev_notify+0x4e8/0x720 net/mpls/af_mpls.c:1657 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:2014 [inline] call_netdevice_notifiers_extack net/core/dev.c:2052 [inline] call_netdevice_notifiers net/core/dev.c:2066 [inline] unregister_netdevice_many+0xe6c/0x177c net/core/dev.c:11003 sit_exit_batch_net+0x444/0x49c net/ipv6/sit.c:1888 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x650/0xa84 net/core/net_namespace.c:640 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 The buggy address belongs to the object at ffff0000cc86ac00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of 256-byte region [ffff0000cc86ac00, ffff0000cc86ad00) The buggy address belongs to the physical page: page:000000003719021d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10c86a head:000000003719021d order:1 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc000364e500 dead000000000004 ffff0000c0002480 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000cc86ab00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000cc86ab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000cc86ac00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000cc86ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000cc86ad00: 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 ffffffffffffffea KASAN: maybe wild-memory-access in range [0x0003ffffffffff50-0x0003ffffffffff57] 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 swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020ddb9000 [ffffffffffffffea] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 9096 Comm: syz.2.1323 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : dvb_device_open+0xf0/0x388 drivers/media/dvb-core/dvbdev.c:103 lr : dvb_device_open+0xd4/0x388 drivers/media/dvb-core/dvbdev.c:99 sp : ffff800021ce75e0 x29: ffff800021ce75e0 x28: ffff0000d9847ba8 x27: dfff800000000000 x26: ffff70000439cec8 x25: dfff800000000000 x24: 1fffe0001990d583 x23: ffffffffffffffea x22: ffff0000cc86ac18 x21: ffff0000d3639430 x20: ffff0000d9847b80 x19: ffff0000cc86ac00 x18: ffff800011b8bf60 x17: 1fffe00033eac97e x16: ffff80000804309c x15: ffff80001520d000 x14: 0000000000000001 x13: 1ffff00002fbf96c x12: 0000000000080000 x11: 000000000003eab1 x10: ffff80002edc6000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000004 x6 : ffff80000825796c x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800008193d00 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000001 Call trace: dvb_device_open+0xf0/0x388 drivers/media/dvb-core/dvbdev.c:103 chrdev_open+0x3d4/0x518 fs/char_dev.c:414 do_dentry_open+0x72c/0xf98 fs/open.c:882 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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: 38796908 34000068 aa1703e0 969e1bb6 (f94002e0) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 38796908 ldrb w8, [x8, x25] 4: 34000068 cbz w8, 0x10 8: aa1703e0 mov x0, x23 c: 969e1bb6 bl 0xfffffffffa786ee4 * 10: f94002e0 ldr x0, [x23] <-- trapping instruction