kobject: 'loop5' (000000004ee1fa21): kobject_uevent_env kobject: 'loop5' (000000004ee1fa21): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop2' (000000005e8ccccc): kobject_uevent_env kobject: 'loop2' (000000005e8ccccc): fill_kobj_path: path = '/devices/virtual/block/loop2' ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:348 [inline] BUG: KASAN: use-after-free in soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70 Read of size 5 at addr ffff888095a56546 by task syz-executor.4/9934 CPU: 0 PID: 9934 Comm: syz-executor.4 Not tainted 4.19.88-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x123/0x190 mm/kasan/kasan.c:267 memcpy+0x24/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:348 [inline] soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x12fc/0x1a60 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x58a/0x7b0 drivers/video/fbdev/core/fbcon.c:1369 hide_cursor+0x9e/0x300 drivers/tty/vt/vt.c:895 redraw_screen+0x2ee/0x8e0 drivers/tty/vt/vt.c:988 vc_do_resize+0x118e/0x14a0 drivers/tty/vt/vt.c:1287 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1307 vt_ioctl+0x1fe0/0x2530 drivers/tty/vt/vt_ioctl.c:887 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a6f9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007efc6e294c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a6f9 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007efc6e2956d4 R13: 00000000004c6e03 R14: 00000000004dd488 R15: 00000000ffffffff Allocated by task 26781: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] rpc_mkpipe_data+0x4a/0x470 net/sunrpc/rpc_pipe.c:572 rpc_pipefs_init_net+0x19c/0x370 net/sunrpc/rpc_pipe.c:1202 sunrpc_init_net+0x2c5/0x3a0 net/sunrpc/sunrpc_syms.c:47 ops_init+0xb3/0x410 net/core/net_namespace.c:129 setup_net+0x2d3/0x740 net/core/net_namespace.c:315 copy_net_ns+0x1df/0x33c net/core/net_namespace.c:438 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2520 __do_sys_unshare kernel/fork.c:2588 [inline] __se_sys_unshare kernel/fork.c:2586 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2586 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 412: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 rpc_destroy_pipe_data net/sunrpc/rpc_pipe.c:564 [inline] rpc_pipefs_exit_net+0x1b4/0x2c0 net/sunrpc/rpc_pipe.c:1215 sunrpc_exit_net+0x16f/0x2d0 net/sunrpc/sunrpc_syms.c:70 ops_exit_list.isra.0+0xaa/0x150 net/core/net_namespace.c:153 cleanup_net+0x404/0x960 net/core/net_namespace.c:553 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 The buggy address belongs to the object at ffff888095a56540 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 6 bytes inside of 512-byte region [ffff888095a56540, ffff888095a56740) The buggy address belongs to the page: page:ffffea0002569580 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff888095a562c0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea00022cb3c8 ffffea0002029dc8 ffff88812c31c940 raw: ffff888095a562c0 ffff888095a56040 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888095a56400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095a56480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff888095a56500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff888095a56580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095a56600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================