================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x360 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff888142bd5818 by task syz.7.3267/17580 CPU: 0 UID: 0 PID: 17580 Comm: syz.7.3267 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 dvb_device_open+0xc4/0x360 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7d0/0x1270 fs/open.c:962 vfs_open+0x3b/0x350 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x34c9/0x3e70 fs/namei.c:4796 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f78b82bb78e 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:00007f78b654db28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f78b654e6c0 RCX: 00007f78b82bb78e RDX: 0000000000040002 RSI: 00007f78b654dc00 RDI: ffffffffffffff9c RBP: 00007f78b654dc00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f78b8576038 R14: 00007f78b8575fa0 R15: 00007ffc5048b7f8 Allocated by task 1: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x1f2/0x6b0 mm/slub.c:5780 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475 dvb_register_frontend+0x665/0x970 drivers/media/dvb-core/dvb_frontend.c:3051 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline] vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508 platform_probe+0xf9/0x190 drivers/base/platform.c:1446 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:661 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833 __driver_attach+0x349/0x640 drivers/base/dd.c:1227 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x348/0x670 drivers/base/bus.c:715 driver_register+0x23a/0x320 drivers/base/driver.c:249 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598 do_one_initcall+0x250/0x840 init/main.c:1378 do_initcall_level+0x104/0x190 init/main.c:1440 do_initcalls+0x59/0xa0 init/main.c:1456 kernel_init_freeable+0x2a6/0x3d0 init/main.c:1688 kernel_init+0x1d/0x1d0 init/main.c:1578 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 17522: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1bb/0x8f0 mm/slub.c:6886 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:632 [inline] dvb_device_open+0x2d6/0x360 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7d0/0x1270 fs/open.c:962 vfs_open+0x3b/0x350 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x34c9/0x3e70 fs/namei.c:4796 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888142bd5800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of freed 512-byte region [ffff888142bd5800, ffff888142bd5a00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888142bd4800 pfn:0x142bd4 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x500000000000240(workingset|head|node=1|zone=2) page_type: f5(slab) raw: 0500000000000240 ffff88813fe26c80 ffffea0005380310 ffff888140400a88 raw: ffff888142bd4800 000000000010000d 00000000f5000000 0000000000000000 head: 0500000000000240 ffff88813fe26c80 ffffea0005380310 ffff888140400a88 head: ffff888142bd4800 000000000010000d 00000000f5000000 0000000000000000 head: 0500000000000002 ffffea00050af501 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 24387364673, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3a0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x100/0x6b0 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] device_private_init drivers/base/core.c:3534 [inline] device_add+0xbe/0xb80 drivers/base/core.c:3585 device_create_groups_vargs drivers/base/core.c:4371 [inline] device_create+0x269/0x300 drivers/base/core.c:4410 mon_bin_add+0xb6/0x130 drivers/usb/mon/mon_bin.c:1372 mon_bus_init+0x173/0x2b0 drivers/usb/mon/mon_main.c:291 mon_bus_add drivers/usb/mon/mon_main.c:188 [inline] mon_notify+0x112/0x400 drivers/usb/mon/mon_main.c:219 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 usb_register_bus+0xcf/0x150 drivers/usb/core/hcd.c:908 page_owner free stack trace missing Memory state around the buggy address: ffff888142bd5700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888142bd5780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888142bd5800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888142bd5880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888142bd5900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================