================================================================== BUG: KASAN: use-after-free in dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff88802996e818 by task syz.2.938/9377 CPU: 1 PID: 9377 Comm: syz.2.938 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3834 do_filp_open+0x1ee/0x420 fs/namei.c:3861 do_sys_openat2+0x14b/0x4f0 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] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc58b55e98e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007fc58c431b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc58c4326c0 RCX: 00007fc58b55e98e RDX: 0000000000040002 RSI: 00007fc58c431c00 RDI: ffffffffffffff9c RBP: 00007fc58c431c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fc58b826128 R14: 00007fc58b826090 R15: 00007ffd0c7b4198 Allocated by task 9323: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] snd_rawmidi_runtime_create sound/core/rawmidi.c:164 [inline] open_substream+0xaf/0x6c0 sound/core/rawmidi.c:341 rawmidi_open_priv+0xc4/0x620 sound/core/rawmidi.c:394 snd_rawmidi_open+0x45e/0xae0 sound/core/rawmidi.c:492 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3834 do_filp_open+0x1ee/0x420 fs/namei.c:3861 do_sys_openat2+0x14b/0x4f0 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] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 9323: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 snd_rawmidi_runtime_free sound/core/rawmidi.c:192 [inline] close_substream+0x4c7/0x750 sound/core/rawmidi.c:570 rawmidi_release_priv+0xe6/0x170 sound/core/rawmidi.c:587 snd_rawmidi_release+0x5a/0xc0 sound/core/rawmidi.c:618 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x118d/0x1340 kernel/signal.c:2657 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x950 kernel/rcu/tree.c:2849 free_fib_info net/ipv4/fib_semantics.c:257 [inline] fib_info_put include/net/ip_fib.h:582 [inline] fib_release_info+0x682/0x740 net/ipv4/fib_semantics.c:283 fib_table_delete+0xdb1/0xfc0 net/ipv4/fib_trie.c:1757 fib_magic+0x2ea/0x3b0 net/ipv4/fib_frontend.c:1120 fib_del_ifaddr+0x10b2/0x14c0 net/ipv4/fib_frontend.c:1331 fib_inetaddr_event+0xb7/0x1c0 net/ipv4/fib_frontend.c:1462 notifier_call_chain kernel/notifier.c:87 [inline] blocking_notifier_call_chain+0x103/0x1b0 kernel/notifier.c:382 __inet_del_ifa+0xaac/0x1090 net/ipv4/devinet.c:445 inet_del_ifa net/ipv4/devinet.c:482 [inline] inetdev_destroy net/ipv4/devinet.c:323 [inline] inetdev_event+0x5ae/0x13f0 net/ipv4/devinet.c:1615 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline] call_netdevice_notifiers net/core/dev.c:2066 [inline] unregister_netdevice_many_notify+0x10b1/0x1990 net/core/dev.c:11023 ip_tunnel_delete_nets+0x326/0x370 net/ipv4/ip_tunnel.c:1157 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x78e/0xba0 net/core/net_namespace.c:640 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 kvfree_call_rcu+0x103/0x890 kernel/rcu/tree.c:3405 drop_sysctl_table+0x359/0x4e0 fs/proc/proc_sysctl.c:1731 drop_sysctl_table+0x348/0x4e0 fs/proc/proc_sysctl.c:1734 unregister_sysctl_table+0x85/0x130 fs/proc/proc_sysctl.c:1769 __devinet_sysctl_unregister net/ipv4/devinet.c:2635 [inline] devinet_exit_net+0x196/0x220 net/ipv4/devinet.c:2780 ops_exit_list net/core/net_namespace.c:172 [inline] setup_net+0x91b/0xbd0 net/core/net_namespace.c:368 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:508 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3285 __do_sys_unshare kernel/fork.c:3359 [inline] __se_sys_unshare kernel/fork.c:3357 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3357 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88802996e800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of 256-byte region [ffff88802996e800, ffff88802996e900) The buggy address belongs to the physical page: page:ffffea0000a65b80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2996e head:ffffea0000a65b80 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001d06b80 dead000000000004 ffff888017441b40 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 15824266809, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115 alloc_slab_page+0x5d/0x180 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2d0 mm/slub.c:1997 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] bus_add_driver+0xdc/0x5d0 drivers/base/bus.c:604 driver_register+0x32d/0x430 drivers/base/driver.c:246 usb_register_driver+0x201/0x3c0 drivers/usb/core/driver.c:1062 do_one_initcall+0x257/0x800 init/main.c:1270 do_initcall_level+0x13d/0x1ed init/main.c:1343 do_initcalls+0x4b/0x8a init/main.c:1359 kernel_init_freeable+0x401/0x5ab init/main.c:1598 page_owner free stack trace missing Memory state around the buggy address: ffff88802996e700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802996e780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802996e800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802996e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802996e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================