================================================================== 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 ffff88802ce95818 by task syz.8.5310/25934 CPU: 0 UID: 0 PID: 25934 Comm: syz.8.5310 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:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 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+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f806c95c84e 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:00007f806d870b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f806d8716c0 RCX: 00007f806c95c84e RDX: 0000000000040002 RSI: 00007f806d870c00 RDI: ffffffffffffff9c RBP: 00007f806d870c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f806cc16038 R14: 00007f806cc15fa0 R15: 00007ffcc5e7dc78 Allocated by task 25670: 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 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] __mmu_notifier_register+0x4a3/0x780 mm/mmu_notifier.c:621 mmu_notifier_register+0x74/0x1c0 mm/mmu_notifier.c:705 kvm_init_mmu_notifier virt/kvm/kvm_main.c:901 [inline] kvm_create_vm virt/kvm/kvm_main.c:1205 [inline] kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5514 [inline] kvm_dev_ioctl+0xdde/0x1a80 virt/kvm/kvm_main.c:5556 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 25670: 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:2670 [inline] slab_free mm/slub.c:6082 [inline] kfree+0x1aa/0x670 mm/slub.c:6399 __mmu_notifier_subscriptions_destroy+0x62/0xc0 mm/mmu_notifier.c:783 mmu_notifier_subscriptions_destroy include/linux/mmu_notifier.h:490 [inline] __mmdrop+0x5d3/0x750 kernel/fork.c:730 mmdrop include/linux/sched/mm.h:55 [inline] __mmput+0x379/0x410 kernel/fork.c:1186 mmput+0x67/0x80 kernel/fork.c:1197 exit_mm kernel/exit.c:581 [inline] do_exit+0x78a/0x2a30 kernel/exit.c:959 do_group_exit+0xd5/0x2a0 kernel/exit.c:1112 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802ce95800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802ce95800, ffff88802ce95900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802ce95800 pfn:0x2ce94 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 ffff88801b842b40 ffffea0000d51e90 ffffea0000b02190 raw: ffff88802ce95800 000000000010000d 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b842b40 ffffea0000d51e90 ffffea0000b02190 head: ffff88802ce95800 000000000010000d 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000b3a501 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 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 19420169123, 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+0x111d/0x3140 mm/page_alloc.c:3950 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5245 alloc_slab_page mm/slub.c:3238 [inline] allocate_slab mm/slub.c:3411 [inline] new_slab+0xa6/0x6e0 mm/slub.c:3469 refill_objects+0x26b/0x400 mm/slub.c:7091 refill_sheaf mm/slub.c:2787 [inline] alloc_full_sheaf mm/slub.c:2808 [inline] __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4546 alloc_from_pcs mm/slub.c:4639 [inline] slab_alloc_node mm/slub.c:4773 [inline] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5292 kmalloc_noprof include/linux/slab.h:962 [inline] usb_string+0x10f/0x570 drivers/usb/core/message.c:980 usb_cache_string+0x80/0x140 drivers/usb/core/message.c:1030 usb_enumerate_device drivers/usb/core/hub.c:2540 [inline] usb_new_device+0x239/0x7d0 drivers/usb/core/hub.c:2665 register_root_hub+0x4e6/0x639 drivers/usb/core/hcd.c:994 usb_add_hcd.cold+0xccd/0x1158 drivers/usb/core/hcd.c:2993 vhci_hcd_probe+0x1c2/0x4e0 drivers/usb/usbip/vhci_hcd.c:1401 platform_probe+0x106/0x1d0 drivers/base/platform.c:1446 call_driver_probe drivers/base/dd.c:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 page_owner free stack trace missing Memory state around the buggy address: ffff88802ce95700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802ce95780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802ce95800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802ce95880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ce95900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================