================================================================== 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 ffff88802d7ec818 by task syz.6.5131/23857 CPU: 3 UID: 0 PID: 23857 Comm: syz.6.5131 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_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:996 vfs_open+0x82/0x3f0 fs/open.c:1101 do_open fs/namei.c:4837 [inline] path_openat+0x19fa/0x2440 fs/namei.c:5000 do_file_open+0x20e/0x430 fs/namei.c:5029 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f337eb5e90e 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:00007f337f9d9b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f337f9da6c0 RCX: 00007f337eb5e90e RDX: 0000000000000002 RSI: 00007f337f9d9c00 RDI: ffffffffffffff9c RBP: 00007f337f9d9c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f337ee26038 R14: 00007f337ee25fa0 R15: 00007ffeac0625c8 Allocated by task 23668: 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:5334 [inline] __kmalloc_noprof+0x324/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kmalloc_array_noprof include/linux/slab.h:1208 [inline] security_inode_init_security+0x113/0x370 security/security.c:1347 shmem_symlink+0x163/0xa00 mm/shmem.c:4044 vfs_symlink fs/namei.c:5794 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5773 filename_symlinkat+0x2a6/0x560 fs/namei.c:5819 __do_sys_symlinkat fs/namei.c:5839 [inline] __se_sys_symlinkat fs/namei.c:5834 [inline] __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 23668: 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:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x22b/0x6c0 mm/slub.c:6692 security_inode_init_security+0x2bf/0x370 security/security.c:1374 shmem_symlink+0x163/0xa00 mm/shmem.c:4044 vfs_symlink fs/namei.c:5794 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5773 filename_symlinkat+0x2a6/0x560 fs/namei.c:5819 __do_sys_symlinkat fs/namei.c:5839 [inline] __se_sys_symlinkat fs/namei.c:5834 [inline] __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802d7ec800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802d7ec800, ffff88802d7ec900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802d7ec800 pfn:0x2d7ec 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 ffff88801c042b40 ffffea00012a5910 ffffea0001572290 raw: ffff88802d7ec800 000000080010000e 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801c042b40 ffffea00012a5910 ffffea0001572290 head: ffff88802d7ec800 000000080010000e 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 13337511817, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf46/0x3500 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab mm/slub.c:3380 [inline] new_slab+0xa2/0x660 mm/slub.c:3426 refill_objects+0xe3/0x410 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __kmalloc_cache_noprof+0x47b/0x6b0 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] bus_add_driver+0x92/0x5b0 drivers/base/bus.c:747 driver_register+0x1e2/0x360 drivers/base/driver.c:174 usb_register_driver drivers/usb/core/driver.c:1078 [inline] usb_register_driver+0x21c/0x3e0 drivers/usb/core/driver.c:1060 do_one_initcall+0x11c/0x6f0 init/main.c:1353 do_initcall_level init/main.c:1415 [inline] do_initcalls init/main.c:1431 [inline] do_basic_setup init/main.c:1451 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1666 kernel_init+0x21/0x1e0 init/main.c:1556 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_owner free stack trace missing Memory state around the buggy address: ffff88802d7ec700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802d7ec780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802d7ec800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802d7ec880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802d7ec900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================