================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff8881067e0c18 by task syz.4.3005/20828 CPU: 3 UID: 0 PID: 20828 Comm: syz.4.3005 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595 dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x234/0x6a0 fs/char_dev.c:414 do_dentry_open+0x73e/0x1570 fs/open.c:962 vfs_open+0x82/0x3f0 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x21dc/0x3120 fs/namei.c:4796 do_filp_open+0x1f7/0x420 fs/namei.c:4823 do_sys_openat2+0x12e/0x220 fs/open.c:1430 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+0x12d/0x210 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcb6ff5b78e 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:00007fcb70d7ab28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fcb70d7b6c0 RCX: 00007fcb6ff5b78e RDX: 0000000000000002 RSI: 00007fcb70d7ac00 RDI: ffffffffffffff9c RBP: 00007fcb70d7ac00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fcb70216038 R14: 00007fcb70215fa0 R15: 00007ffc22ca7ad8 Allocated by task 19812: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_node_noprof+0x359/0x9e0 mm/slub.c:5663 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x46/0x110 mm/slub.c:2123 account_slab mm/slub.c:3202 [inline] allocate_slab mm/slub.c:3267 [inline] new_slab+0x354/0x440 mm/slub.c:3302 ___slab_alloc+0xda3/0x1ca0 mm/slub.c:4656 __kmem_cache_alloc_bulk+0x20f/0x700 mm/slub.c:7435 refill_sheaf mm/slub.c:2650 [inline] alloc_full_sheaf mm/slub.c:2671 [inline] __pcs_replace_empty_main+0x347/0x4f0 mm/slub.c:5033 alloc_from_pcs mm/slub.c:5121 [inline] slab_alloc_node mm/slub.c:5248 [inline] kmem_cache_alloc_noprof+0x602/0x780 mm/slub.c:5270 vm_area_dup+0x27/0x8e0 mm/vma_init.c:123 dup_mmap+0x6a4/0x1e20 mm/mmap.c:1773 dup_mm kernel/fork.c:1529 [inline] copy_mm kernel/fork.c:1581 [inline] copy_process+0x7451/0x7890 kernel/fork.c:2221 kernel_clone+0xfc/0x930 kernel/fork.c:2651 __do_sys_clone+0xd9/0x120 kernel/fork.c:2792 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 0: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1c7/0x690 mm/slub.c:6882 free_slab_obj_exts mm/slub.c:2203 [inline] unaccount_slab mm/slub.c:3216 [inline] __free_slab+0x101/0x150 mm/slub.c:3316 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x7c0/0x15c0 kernel/rcu/tree.c:2857 handle_softirqs+0x1ea/0x910 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 The buggy address belongs to the object at ffff8881067e0c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff8881067e0c00, ffff8881067e0d00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881067e0c00 pfn:0x1067e0 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 057ff00000000240 ffff88801b842b40 ffffea000408ae90 ffffea000407fc90 raw: ffff8881067e0c00 000000000010000f 00000000f5000000 0000000000000000 head: 057ff00000000240 ffff88801b842b40 ffffea000408ae90 ffffea000407fc90 head: ffff8881067e0c00 000000000010000f 00000000f5000000 0000000000000000 head: 057ff00000000001 ffffea000419f801 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 24229740646, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c4/0x440 mm/slub.c:3302 ___slab_alloc+0xda3/0x1ca0 mm/slub.c:4656 __slab_alloc.isra.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x531/0x810 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] bus_add_driver+0x92/0x5b0 drivers/base/bus.c:699 driver_register+0x1e2/0x360 drivers/base/driver.c:249 usb_register_driver drivers/usb/core/driver.c:1078 [inline] usb_register_driver+0x21c/0x3e0 drivers/usb/core/driver.c:1060 pvr_init+0xa1/0x130 drivers/media/usb/pvrusb2/pvrusb2-main.c:112 do_one_initcall+0x11d/0x690 init/main.c:1378 do_initcall_level init/main.c:1440 [inline] do_initcalls init/main.c:1456 [inline] do_basic_setup init/main.c:1475 [inline] kernel_init_freeable+0x6e5/0x790 init/main.c:1688 kernel_init+0x1f/0x1e0 init/main.c:1578 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff8881067e0b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881067e0b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881067e0c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881067e0c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881067e0d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================