================================================================== BUG: KASAN: use-after-free in dvb_frontend_release+0x3f5/0x490 drivers/media/dvb-core/dvb_frontend.c:2900 Read of size 4 at addr ffff8880291a8e3c by task syz.3.66/4693 CPU: 1 PID: 4693 Comm: syz.3.66 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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_frontend_release+0x3f5/0x490 drivers/media/dvb-core/dvb_frontend.c:2900 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 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 RIP: 0033:0x7f40b279ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd11a2d7d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f40b2a17da0 RCX: 00007f40b279ce59 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f40b2a17da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007f40b2a17cb0 R11: 0000000000000246 R12: 0000000000020d80 R13: 00007f40b2a1609c R14: 0000000000020d4e R15: 00007f40b2a16090 Allocated by task 1: 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] dvb_register_device+0x305/0x1dc0 drivers/media/dvb-core/dvbdev.c:478 dvb_register_frontend+0x629/0x900 drivers/media/dvb-core/dvb_frontend.c:3035 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline] vidtv_bridge_probe+0x9cf/0xf50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510 platform_probe+0x137/0x1c0 drivers/base/platform.c:1400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x24a/0xb40 drivers/base/dd.c:639 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:805 driver_probe_device+0x4f/0x420 drivers/base/dd.c:835 __driver_attach+0x43d/0x6c0 drivers/base/dd.c:1221 bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303 bus_add_driver+0x324/0x5d0 drivers/base/bus.c:620 driver_register+0x32d/0x430 drivers/base/driver.c:246 vidtv_bridge_init+0x39/0x67 drivers/media/test-drivers/vidtv/vidtv_bridge.c:602 do_one_initcall+0x257/0x800 init/main.c:1309 do_initcall_level+0x13d/0x1ed init/main.c:1382 do_initcalls+0x4b/0x8a init/main.c:1398 kernel_init_freeable+0x401/0x5ab init/main.c:1637 kernel_init+0x19/0x1b0 init/main.c:1525 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 4693: 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 dvb_free_device drivers/media/dvb-core/dvbdev.c:625 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:640 [inline] dvb_generic_release+0x11c/0x1b0 drivers/media/dvb-core/dvbdev.c:173 dvb_frontend_release+0x131/0x490 drivers/media/dvb-core/dvb_frontend.c:2898 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 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 The buggy address belongs to the object at ffff8880291a8e00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 60 bytes inside of 256-byte region [ffff8880291a8e00, ffff8880291a8f00) The buggy address belongs to the physical page: page:ffffea0000a46a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x291a8 head:ffffea0000a46a00 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 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 2, tgid 2 (kthreadd), ts 19586583140, 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_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] set_kthread_struct+0xb3/0x1f0 kernel/kthread.c:117 copy_process+0x1366/0x40c0 kernel/fork.c:2284 kernel_clone+0x24b/0x900 kernel/fork.c:2764 kernel_thread+0x118/0x180 kernel/fork.c:2824 create_kthread kernel/kthread.c:399 [inline] kthreadd+0x54f/0x700 kernel/kthread.c:748 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 page_owner free stack trace missing Memory state around the buggy address: ffff8880291a8d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880291a8d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880291a8e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880291a8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880291a8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================