kcov: kcov_start: t = ffff88801d790000, size = 524288, area = ffffc90018c34000 ================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x340 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff88802b34a818 by task syz.5.4582/23214 CPU: 0 UID: 0 PID: 23214 Comm: syz.5.4582 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 dvb_device_open+0xc4/0x340 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x4d9/0x600 fs/char_dev.c:413 do_dentry_open+0x80e/0x1360 fs/open.c:1000 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4844 [inline] path_openat+0x14a6/0x1da0 fs/namei.c:5009 do_file_open+0x23e/0x4a0 fs/namei.c:5038 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdc53d5e98e 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:00007fdc51ff5b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fdc51ff66c0 RCX: 00007fdc53d5e98e RDX: 0000000000040002 RSI: 00007fdc51ff5c00 RDI: ffffffffffffff9c RBP: 00007fdc51ff5c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fdc54026218 R14: 00007fdc54026180 R15: 00007fff50420ea8 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:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x600 mm/slub.c:5680 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] dvb_register_device+0x309/0x1dd0 drivers/media/dvb-core/dvbdev.c:472 dvb_register_frontend+0x603/0x900 drivers/media/dvb-core/dvb_frontend.c:3074 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:507 [inline] vidtv_bridge_probe+0xab2/0x10e0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:580 platform_probe+0xf9/0x190 drivers/base/platform.c:1507 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:386 bus_add_driver+0x345/0x670 drivers/base/bus.c:766 driver_register+0x23a/0x320 drivers/base/driver.c:174 vidtv_bridge_init+0x3d/0x60 drivers/media/test-drivers/vidtv/vidtv_bridge.c:675 do_one_initcall+0x250/0x870 init/main.c:1360 do_initcall_level+0x10a/0x1a0 init/main.c:1422 do_initcalls+0x59/0xa0 init/main.c:1438 kernel_init_freeable+0x29d/0x3e0 init/main.c:1673 kernel_init+0x22/0x1d0 init/main.c:1563 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 23144: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2780 [inline] slab_free mm/slub.c:6630 [inline] kfree+0x1c5/0x650 mm/slub.c:6923 dvb_free_device drivers/media/dvb-core/dvbdev.c:616 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:629 [inline] dvb_device_open+0x2b8/0x340 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x4d9/0x600 fs/char_dev.c:413 do_dentry_open+0x80e/0x1360 fs/open.c:1000 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4844 [inline] path_openat+0x14a6/0x1da0 fs/namei.c:5009 do_file_open+0x23e/0x4a0 fs/namei.c:5038 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802b34a800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802b34a800, ffff88802b34a900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b34a head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b041b40 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b041b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 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 18369424478 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1854 prep_new_page mm/page_alloc.c:1862 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3933 __alloc_frozen_pages_noprof+0x1fc/0x400 mm/page_alloc.c:5441 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab+0x7d/0x5e0 mm/slub.c:3499 new_slab mm/slub.c:3550 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __kmalloc_cache_noprof+0x396/0x600 mm/slub.c:5676 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] bus_add_driver+0x162/0x670 drivers/base/bus.c:750 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1084 pvr_init+0x4c/0xb0 drivers/media/usb/pvrusb2/pvrusb2-main.c:112 do_one_initcall+0x250/0x870 init/main.c:1360 do_initcall_level+0x10a/0x1a0 init/main.c:1422 do_initcalls+0x59/0xa0 init/main.c:1438 kernel_init_freeable+0x29d/0x3e0 init/main.c:1673 kernel_init+0x22/0x1d0 init/main.c:1563 page_owner free stack trace missing Memory state around the buggy address: ffff88802b34a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802b34a780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802b34a800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b34a880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b34a900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================