================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff888141667218 by task syz.0.778/8681 CPU: 0 PID: 8681 Comm: syz.0.778 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xa8/0x210 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3640 [inline] path_openat+0x27f1/0x3230 fs/namei.c:3797 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 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+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f0e2635cfce 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:00007f0e271c0b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0e271c16c0 RCX: 00007f0e2635cfce RDX: 0000000000044e02 RSI: 00007f0e271c0c00 RDI: ffffffffffffff9c RBP: 00007f0e271c0c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f0e26616038 R14: 00007f0e26615fa0 R15: 00007ffcb0bc0d38 Allocated by task 8656: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc+0xb4/0x230 mm/slab_common.c:1020 kmalloc_array include/linux/slab.h:637 [inline] kcalloc include/linux/slab.h:668 [inline] __list_lru_init+0xa6/0x5f0 mm/list_lru.c:571 alloc_super+0x74a/0x920 fs/super.c:393 sget_fc+0x322/0x8d0 fs/super.c:805 vfs_get_super fs/super.c:1341 [inline] get_tree_nodev+0x2a/0x140 fs/super.c:1365 vfs_get_tree+0x8c/0x280 fs/super.c:1764 fc_mount+0x1c/0xb0 fs/namespace.c:1117 mq_create_mount ipc/mqueue.c:485 [inline] mq_init_ns+0x3a1/0x510 ipc/mqueue.c:1699 create_ipc_ns ipc/namespace.c:73 [inline] copy_ipcs+0x309/0x500 ipc/namespace.c:114 create_new_namespaces+0x212/0x6f0 kernel/nsproxy.c:90 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:228 ksys_unshare+0x4ce/0x8b0 kernel/fork.c:3439 __do_sys_unshare kernel/fork.c:3510 [inline] __se_sys_unshare kernel/fork.c:3508 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3508 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 788: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843 list_lru_destroy+0x55c/0x630 mm/list_lru.c:598 deactivate_locked_super+0xab/0x100 fs/super.c:490 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259 mntput_no_expire+0x7cf/0x870 fs/namespace.c:1345 free_ipc_ns ipc/namespace.c:154 [inline] free_ipc+0x107/0x270 ipc/namespace.c:181 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 The buggy address belongs to the object at ffff888141667200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff888141667200, ffff888141667300) The buggy address belongs to the physical page: page:ffffea0005059980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x141666 head:ffffea0005059980 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0x57ff00000000840(slab|head|node=1|zone=2|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 057ff00000000840 ffff888017c41b40 ffffea0000b77680 0000000000000003 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 1, tgid 1 (swapper/0), ts 36365971324, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581 prep_new_page mm/page_alloc.c:1588 [inline] get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120 alloc_slab_page+0x5d/0x160 mm/slub.c:1881 allocate_slab mm/slub.c:2028 [inline] new_slab+0x87/0x2d0 mm/slub.c:2081 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253 __slab_alloc mm/slub.c:3339 [inline] __slab_alloc_node mm/slub.c:3392 [inline] slab_alloc_node mm/slub.c:3485 [inline] __kmem_cache_alloc_node+0x19e/0x250 mm/slub.c:3534 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] bus_add_driver+0x162/0x630 drivers/base/bus.c:659 driver_register+0x23a/0x310 drivers/base/driver.c:246 usb_register_driver+0x206/0x3d0 drivers/usb/core/driver.c:1062 do_one_initcall+0x242/0x790 init/main.c:1250 do_initcall_level+0x137/0x1f0 init/main.c:1312 do_initcalls+0x69/0xd0 init/main.c:1328 kernel_init_freeable+0x3ed/0x580 init/main.c:1565 page_owner free stack trace missing Memory state around the buggy address: ffff888141667100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888141667180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888141667200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888141667280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888141667300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================