================================================================== 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 ffff88802f2e7618 by task syz.0.237/6377 CPU: 0 UID: 0 PID: 6377 Comm: syz.0.237 Not tainted syzkaller #0 PREEMPT(full) 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_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6ab/0x14d0 fs/open.c:947 vfs_open+0x82/0x3f0 fs/open.c:1079 do_open fs/namei.c:4700 [inline] path_openat+0x2873/0x4280 fs/namei.c:4859 do_file_open+0x20e/0x430 fs/namei.c:4888 do_sys_openat2+0x10f/0x1e0 fs/open.c:1395 do_sys_open fs/open.c:1401 [inline] __do_sys_openat fs/open.c:1417 [inline] __se_sys_openat fs/open.c:1412 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1412 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f72cd95d68e 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:00007fff73b68248 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00005555760e8500 RCX: 00007f72cd95d68e RDX: 0000000000000002 RSI: 00007fff73b68320 RDI: ffffffffffffff9c RBP: 00007fff73b68320 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f72cdc15fac R14: 00007f72cdc15fa0 R15: 00007f72cdc15fa0 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:969 [inline] _kzalloc_noprof include/linux/slab.h:1286 [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:3051 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:1439 call_driver_probe drivers/base/dd.c:628 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:706 __driver_probe_device+0x20e/0x450 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+0x3f/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600 do_one_initcall+0x11d/0x700 init/main.c:1347 do_initcall_level init/main.c:1409 [inline] do_initcalls init/main.c:1425 [inline] do_basic_setup init/main.c:1445 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1658 kernel_init+0x1f/0x1e0 init/main.c:1548 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 6376: 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:2700 [inline] slab_free mm/slub.c:6310 [inline] kfree+0x22b/0x6c0 mm/slub.c:6625 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:628 [inline] dvb_device_open+0x2ba/0x3b0 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6ab/0x14d0 fs/open.c:947 vfs_open+0x82/0x3f0 fs/open.c:1079 do_open fs/namei.c:4700 [inline] path_openat+0x2873/0x4280 fs/namei.c:4859 do_file_open+0x20e/0x430 fs/namei.c:4888 do_sys_openat2+0x10f/0x1e0 fs/open.c:1395 do_sys_open fs/open.c:1401 [inline] __do_sys_openat fs/open.c:1417 [inline] __se_sys_openat fs/open.c:1412 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1412 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802f2e7600 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802f2e7600, ffff88802f2e7700) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2f2e6 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 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 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 17713051090, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x812/0x3d20 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221 alloc_slab_page mm/slub.c:3289 [inline] allocate_slab mm/slub.c:3404 [inline] new_slab+0xa2/0x670 mm/slub.c:3447 refill_objects+0xe3/0x430 mm/slub.c:7241 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x375/0x660 mm/slub.c:4692 alloc_from_pcs mm/slub.c:4790 [inline] slab_alloc_node mm/slub.c:4924 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x67e/0x840 mm/slub.c:5347 _kmalloc_noprof include/linux/slab.h:973 [inline] _kzalloc_noprof include/linux/slab.h:1286 [inline] rh_call_control drivers/usb/core/hcd.c:485 [inline] rh_urb_enqueue drivers/usb/core/hcd.c:815 [inline] usb_hcd_submit_urb+0x601/0x2150 drivers/usb/core/hcd.c:1536 usb_submit_urb+0x827/0x19b0 drivers/usb/core/urb.c:586 usb_start_wait_urb+0x10e/0x580 drivers/usb/core/message.c:62 usb_internal_control_msg drivers/usb/core/message.c:117 [inline] usb_control_msg+0x328/0x4b0 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:2537 [inline] usb_new_device+0x166/0x7d0 drivers/usb/core/hub.c:2665 page_owner free stack trace missing Memory state around the buggy address: ffff88802f2e7500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802f2e7580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802f2e7600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802f2e7680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802f2e7700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 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