================================================================== BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x4f3/0x5d0 drivers/media/dvb-core/dvb_frontend.c:2939 Read of size 4 at addr ffff8880256cc83c by task syz.3.646/8430 CPU: 0 UID: 0 PID: 8430 Comm: syz.3.646 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+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 dvb_frontend_release+0x4f3/0x5d0 drivers/media/dvb-core/dvb_frontend.c:2939 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 get_signal+0x1bd/0x21e0 kernel/signal.c:2884 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] __do_fast_syscall_32+0x59f/0x8b0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fb5fec Code: Unable to access opcode bytes at 0xf7fb5fc2. RSP: 002b:00000000f545550c EFLAGS: 00000292 ORIG_RAX: 0000000000000134 RAX: 0000000000000007 RBX: 0000000000000040 RCX: 0000000080000240 RDX: 0000000000000000 RSI: 00000000800002c0 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 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:409 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] dvb_register_device+0x1d6/0x1e20 drivers/media/dvb-core/dvbdev.c:472 dvb_register_frontend+0x552/0x820 drivers/media/dvb-core/dvb_frontend.c:3074 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline] vidtv_bridge_probe+0x44b/0xa30 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510 platform_probe+0x106/0x1d0 drivers/base/platform.c:1507 call_driver_probe drivers/base/dd.c:628 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:706 __driver_probe_device+0x210/0x460 drivers/base/dd.c:868 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898 __driver_attach+0x21f/0x5b0 drivers/base/dd.c:1292 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383 bus_add_driver+0x305/0x5b0 drivers/base/bus.c:763 driver_register+0x1e2/0x360 drivers/base/driver.c:174 vidtv_bridge_init+0x52/0x80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:602 do_one_initcall+0x11c/0x6f0 init/main.c:1362 do_initcall_level init/main.c:1424 [inline] do_initcalls init/main.c:1440 [inline] do_basic_setup init/main.c:1460 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1675 kernel_init+0x21/0x1e0 init/main.c:1565 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 8430: 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:264 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x22b/0x6d0 mm/slub.c:6801 dvb_free_device drivers/media/dvb-core/dvbdev.c:616 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put.part.0+0x57/0x90 drivers/media/dvb-core/dvbdev.c:629 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:2937 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 get_signal+0x1bd/0x21e0 kernel/signal.c:2884 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] __do_fast_syscall_32+0x59f/0x8b0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff8880256cc800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 60 bytes inside of freed 256-byte region [ffff8880256cc800, ffff8880256cc900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x256cc 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 ffff88801c042b40 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801c042b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 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 7147764672 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7417 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __kmalloc_cache_noprof+0x4f4/0x6d0 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] bus_add_driver+0x92/0x5b0 drivers/base/bus.c:747 driver_register+0x1e2/0x360 drivers/base/driver.c:174 vidtv_bridge_init+0x52/0x80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:602 do_one_initcall+0x11c/0x6f0 init/main.c:1362 do_initcall_level init/main.c:1424 [inline] do_initcalls init/main.c:1440 [inline] do_basic_setup init/main.c:1460 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1675 kernel_init+0x21/0x1e0 init/main.c:1565 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 1 tgid 1 ts 6831982062 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x2cc/0x840 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] usb_alloc_urb+0x66/0xa0 drivers/usb/core/urb.c:75 usb_internal_control_msg drivers/usb/core/message.c:110 [inline] usb_control_msg+0x1d3/0x4b0 drivers/usb/core/message.c:167 usb_get_string+0xab/0x1a0 drivers/usb/core/message.c:902 usb_string_sub+0x103/0x3b0 drivers/usb/core/message.c:941 usb_string+0x2ff/0x570 drivers/usb/core/message.c:1046 usb_cache_string+0x7c/0x100 drivers/usb/core/message.c:1090 usb_enumerate_device drivers/usb/core/hub.c:2547 [inline] usb_new_device.part.0+0x238/0x1686 drivers/usb/core/hub.c:2678 register_root_hub+0x4e6/0x639 drivers/usb/core/hcd.c:990 usb_add_hcd.cold+0xccd/0x1158 drivers/usb/core/hcd.c:2987 vhci_hcd_probe+0x1c2/0x4e0 drivers/usb/usbip/vhci_hcd.c:1401 platform_probe+0x106/0x1d0 drivers/base/platform.c:1507 Memory state around the buggy address: ffff8880256cc700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880256cc780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880256cc800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880256cc880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880256cc900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 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