================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff88802b3dee18 by task syz.8.780/9445 CPU: 0 UID: 0 PID: 9445 Comm: syz.8.780 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe2a6d5c84e 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:00007fe2a7cd1b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe2a7cd26c0 RCX: 00007fe2a6d5c84e RDX: 0000000000040002 RSI: 00007fe2a7cd1c00 RDI: ffffffffffffff9c RBP: 00007fe2a7cd1c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fe2a7016128 R14: 00007fe2a7016090 R15: 00007fff9dd0e7d8 Allocated by task 9390: 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] __do_kmalloc_node mm/slub.c:5219 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5231 kmalloc_noprof include/linux/slab.h:966 [inline] io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:61 [inline] io_uring_alloc_async_data io_uring/io_uring.h:341 [inline] io_rw_alloc_async io_uring/rw.c:209 [inline] __io_prep_rw+0x2bf/0xed0 io_uring/rw.c:268 io_prep_rw io_uring/rw.c:328 [inline] io_prep_rwv+0x8e/0x440 io_uring/rw.c:350 io_init_req io_uring/io_uring.c:1828 [inline] io_submit_sqe io_uring/io_uring.c:1875 [inline] io_submit_sqes+0xb37/0x2370 io_uring/io_uring.c:2043 __do_sys_io_uring_enter io_uring/io_uring.c:2603 [inline] __se_sys_io_uring_enter+0x2cc/0x18c0 io_uring/io_uring.c:2538 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 9390: 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:2687 [inline] slab_free mm/slub.c:6124 [inline] kfree+0x1c1/0x630 mm/slub.c:6442 io_clean_op+0x298/0x330 io_uring/io_uring.c:323 io_free_batch_list io_uring/io_uring.c:1109 [inline] __io_submit_flush_completions+0xd9a/0xfc0 io_uring/io_uring.c:1147 io_submit_flush_completions io_uring/io_uring.h:238 [inline] io_submit_state_end io_uring/io_uring.c:1934 [inline] io_submit_sqes+0x1db8/0x2370 io_uring/io_uring.c:2058 __do_sys_io_uring_enter io_uring/io_uring.c:2603 [inline] __se_sys_io_uring_enter+0x2cc/0x18c0 io_uring/io_uring.c:2538 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802b3dee00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802b3dee00, ffff88802b3def00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b3de 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 ffff88813fea3b40 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fea3b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000acf781 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 12180231706, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1888 prep_new_page mm/page_alloc.c:1896 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3961 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5249 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab+0x77/0x660 mm/slub.c:3444 new_slab mm/slub.c:3502 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5334 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] bus_add_driver+0x162/0x670 drivers/base/bus.c:699 driver_register+0x23a/0x320 drivers/base/driver.c:249 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff88802b3ded00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802b3ded80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802b3dee00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b3dee80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b3def00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 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