================================================================== 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 ffff88802cbd2818 by task syz.5.5511/26349 CPU: 0 UID: 0 PID: 26349 Comm: syz.5.5511 Tainted: G L Y syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND 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:4893 [inline] path_openat+0x16fc/0x20f0 fs/namei.c:5058 do_file_open+0x258/0x570 fs/namei.c:5087 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1788 [inline] __se_sys_openat fs/open.c:1783 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1783 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: 0033:0x7ff9feb5ed8e 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:00007ff9ffab0b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ff9ffab16c0 RCX: 00007ff9feb5ed8e RDX: 0000000000000002 RSI: 00007ff9ffab0c00 RDI: ffffffffffffff9c RBP: 00007ff9ffab0c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007ff9fee26038 R14: 00007ff9fee25fa0 R15: 00007fff1b608088 Allocated by task 25749: 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] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_noprof+0x366/0x710 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [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:325 [inline] io_rw_alloc_async io_uring/rw.c:197 [inline] __io_prep_rw+0x281/0xe70 io_uring/rw.c:255 io_prep_rw io_uring/rw.c:310 [inline] io_prep_rwv+0x81/0x390 io_uring/rw.c:332 io_init_req io_uring/io_uring.c:1883 [inline] io_submit_sqe io_uring/io_uring.c:1930 [inline] io_submit_sqes+0xbde/0x2310 io_uring/io_uring.c:2098 __do_sys_io_uring_enter io_uring/io_uring.c:2775 [inline] __se_sys_io_uring_enter+0x35b/0x1bb0 io_uring/io_uring.c:2724 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 Freed by task 25749: 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 io_clean_op+0x298/0x330 io_uring/io_uring.c:328 io_free_batch_list io_uring/io_uring.c:1141 [inline] __io_submit_flush_completions+0x10d5/0x1300 io_uring/io_uring.c:1192 io_submit_flush_completions io_uring/io_uring.h:253 [inline] ctx_flush_and_put+0xfc/0x360 io_uring/tw.c:26 tctx_task_work_run+0x78b/0xab0 io_uring/tw.c:113 tctx_task_work+0x3f/0x60 io_uring/tw.c:133 task_work_run+0x1d9/0x260 kernel/task_work.c:233 io_run_task_work+0x3e4/0x560 io_uring/tw.h:84 io_uring_try_cancel_requests+0x4aa/0x540 io_uring/cancel.c:570 io_uring_cancel_generic+0x62c/0x9f0 io_uring/cancel.c:671 io_uring_files_cancel include/linux/io_uring.h:52 [inline] do_exit+0x39f/0x2360 kernel/exit.c:920 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123 get_signal+0x1216/0x12c0 kernel/signal.c:3112 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop kernel/entry/common.c:101 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline] irqentry_exit+0x2c0/0x920 kernel/entry/common.c:152 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 The buggy address belongs to the object at ffff88802cbd2800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802cbd2800, ffff88802cbd2900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802cbd2200 pfn:0x2cbd2 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801c041b40 ffffea00009b3510 ffffea0000ced490 raw: ffff88802cbd2200 000000000010000b 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801c041b40 ffffea00009b3510 ffffea0000ced490 head: ffff88802cbd2200 000000000010000b 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 14937366017 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+0x220f/0x2280 mm/page_alloc.c:3933 __alloc_frozen_pages_noprof+0x1fe/0x410 mm/page_alloc.c:5457 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+0x19d/0x6e0 drivers/base/bus.c:755 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1083 do_one_initcall+0x250/0x870 init/main.c:1419 do_initcall_level+0x10a/0x1a0 init/main.c:1481 do_initcalls+0x59/0xa0 init/main.c:1497 kernel_init_freeable+0x29d/0x3e0 init/main.c:1732 kernel_init+0x22/0x1d0 init/main.c:1622 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff88802cbd2700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802cbd2780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802cbd2800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802cbd2880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802cbd2900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================