================================================================== BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x4f3/0x5d0 drivers/media/dvb-core/dvb_frontend.c:2916 Read of size 4 at addr ffff88802b12a83c by task syz.4.4556/21104 CPU: 0 UID: 0 PID: 21104 Comm: syz.4.4556 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_frontend_release+0x4f3/0x5d0 drivers/media/dvb-core/dvb_frontend.c:2916 __fput+0x3ff/0xb40 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x829/0x2a30 kernel/exit.c:971 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:41 [inline] exit_to_user_mode_loop+0x86/0x4b0 kernel/entry/common.c:75 __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_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x4fe/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f416a35b84e Code: Unable to access opcode bytes at 0x7f416a35b824. RSP: 002b:00007f416b317f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f416b3186c0 RCX: 00007f416a35b84e RDX: 00007f416b317fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f416a4316e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f416a616038 R14: 00007f416a615fa0 R15: 00007ffcaf940938 Allocated by task 1: 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:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] dvb_register_device+0x1d6/0x1e60 drivers/media/dvb-core/dvbdev.c:475 dvb_register_frontend+0x5a8/0x8a0 drivers/media/dvb-core/dvb_frontend.c:3051 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline] vidtv_bridge_probe+0x44b/0xa30 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508 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 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __driver_attach+0x217/0x5c0 drivers/base/dd.c:1227 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383 bus_add_driver+0x305/0x5b0 drivers/base/bus.c:715 driver_register+0x1e2/0x360 drivers/base/driver.c:249 vidtv_bridge_init+0x38/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598 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 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 21104: 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:6886 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put.part.0+0x57/0x90 drivers/media/dvb-core/dvbdev.c:632 dvb_device_put drivers/media/dvb-core/dvbdev.c:171 [inline] dvb_generic_release+0xe2/0x160 drivers/media/dvb-core/dvbdev.c:169 dvb_frontend_release+0x13d/0x5d0 drivers/media/dvb-core/dvb_frontend.c:2914 __fput+0x3ff/0xb40 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x829/0x2a30 kernel/exit.c:971 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:41 [inline] exit_to_user_mode_loop+0x86/0x4b0 kernel/entry/common.c:75 __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_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x4fe/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802b12a800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 60 bytes inside of freed 256-byte region [ffff88802b12a800, ffff88802b12a900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b12a 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 ffff88801b842b40 ffffea000404a980 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842b40 ffffea000404a980 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000ac4a81 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 36, tgid 36 (kdevtmpfs), ts 19531226924, 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] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x618/0x9c0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kmalloc_array_noprof include/linux/slab.h:1003 [inline] security_inode_init_security+0x113/0x370 security/security.c:1321 shmem_mknod+0x229/0x3b0 mm/shmem.c:3907 shmem_mkdir+0x31/0x80 mm/shmem.c:3961 vfs_mkdir+0x729/0xb50 fs/namei.c:5139 dev_mkdir drivers/base/devtmpfs.c:183 [inline] create_path drivers/base/devtmpfs.c:208 [inline] handle_create drivers/base/devtmpfs.c:227 [inline] handle drivers/base/devtmpfs.c:385 [inline] devtmpfs_work_loop+0x2e3/0xae4 drivers/base/devtmpfs.c:400 devtmpfsd+0x3f/0x50 drivers/base/devtmpfs.c:442 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff88802b12a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802b12a780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802b12a800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b12a880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b12a900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================