================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: use-after-free in bit_putcs+0xc09/0xdb0 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88808ea03974 by task syz-executor.5/15653 CPU: 0 PID: 15653 Comm: syz-executor.5 Not tainted 4.14.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xc09/0xdb0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3c2/0x480 drivers/video/fbdev/core/fbcon.c:1298 con_flush drivers/tty/vt/vt.c:2186 [inline] do_con_write.part.0+0xca3/0x1b50 drivers/tty/vt/vt.c:2433 do_con_write drivers/tty/vt/vt.c:2205 [inline] con_write+0x38/0xc0 drivers/tty/vt/vt.c:2787 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x38b/0xf20 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x3f6/0x700 drivers/tty/tty_io.c:1043 __vfs_write+0x105/0x6b0 fs/read_write.c:480 vfs_write+0x198/0x500 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xfd/0x230 fs/read_write.c:582 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a919 RSP: 002b:00007fa9d055cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a919 RDX: 000000000000050f RSI: 0000000020000600 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa9d055d6d4 R13: 00000000004cbd7a R14: 00000000004e5b48 R15: 00000000ffffffff Allocated by task 22: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3696 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:137 __alloc_skb+0xcf/0x500 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:980 [inline] nlmsg_new include/net/netlink.h:511 [inline] rtmsg_ifinfo_build_skb+0x72/0x140 net/core/rtnetlink.c:2899 rollback_registered_many+0x78f/0xb60 net/core/dev.c:7218 unregister_netdevice_many.part.0+0x1b/0x1e0 net/core/dev.c:8268 unregister_netdevice_many net/core/dev.c:8267 [inline] default_device_exit_batch+0x31e/0x3d0 net/core/dev.c:8729 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:145 cleanup_net+0x3ba/0x870 net/core/net_namespace.c:484 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Freed by task 22: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 skb_free_head+0x8b/0xb0 net/core/skbuff.c:554 pskb_expand_head+0x4a4/0xc10 net/core/skbuff.c:1495 netlink_trim+0x1c1/0x230 net/netlink/af_netlink.c:1268 netlink_broadcast_filtered+0x5c/0x9e0 net/netlink/af_netlink.c:1465 netlink_broadcast net/netlink/af_netlink.c:1510 [inline] nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x140/0x180 net/netlink/af_netlink.c:2475 rtnl_notify net/core/rtnetlink.c:653 [inline] rtmsg_ifinfo_send+0x76/0x8b net/core/rtnetlink.c:2921 rollback_registered_many+0x81e/0xb60 net/core/dev.c:7231 unregister_netdevice_many.part.0+0x1b/0x1e0 net/core/dev.c:8268 unregister_netdevice_many net/core/dev.c:8267 [inline] default_device_exit_batch+0x31e/0x3d0 net/core/dev.c:8729 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:145 cleanup_net+0x3ba/0x870 net/core/net_namespace.c:484 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 The buggy address belongs to the object at ffff88808ea036c0 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 692 bytes inside of 2048-byte region [ffff88808ea036c0, ffff88808ea03ec0) The buggy address belongs to the page: page:ffffea00023a8080 count:1 mapcount:0 mapping:ffff88808ea025c0 index:0xffff88808ea025c0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff88808ea025c0 ffff88808ea025c0 0000000100000002 raw: ffffea0001292220 ffffea0002290520 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ea03800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ea03880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808ea03900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808ea03980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ea03a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================