================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:381 [inline] BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:49 [inline] BUG: KASAN: use-after-free in vc_do_resize+0x888/0x1340 drivers/tty/vt/vt.c:1274 Read of size 2 at addr ffff8880a822171c by task syz-executor.2/13569 CPU: 1 PID: 13569 Comm: syz-executor.2 Not tainted 5.7.0-rc1-next-20200415-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+0x188/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:382 __kasan_report.cold+0x35/0x4d mm/kasan/report.c:511 kasan_report+0x33/0x50 mm/kasan/common.c:625 check_memory_region_inline mm/kasan/generic.c:187 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:193 memcpy+0x20/0x60 mm/kasan/common.c:106 memcpy include/linux/string.h:381 [inline] scr_memcpyw include/linux/vt_buffer.h:49 [inline] vc_do_resize+0x888/0x1340 drivers/tty/vt/vt.c:1274 fbcon_modechanged+0x36e/0x790 drivers/video/fbdev/core/fbcon.c:2989 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3047 fb_set_var+0xad0/0xd40 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0x390/0x6e0 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca29 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7c1526bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e4ac0 RCX: 000000000045ca29 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f2 R14: 00000000004c56c8 R15: 00007f7c1526c6d4 Allocated by task 7250: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x161/0x7a0 mm/slab.c:3665 kmalloc_array include/linux/slab.h:597 [inline] kcalloc include/linux/slab.h:608 [inline] ext4_find_extent+0x7d2/0xa50 fs/ext4/extents.c:860 ext4_ext_map_blocks+0x1af/0x3710 fs/ext4/extents.c:4039 ext4_map_blocks+0xcd3/0x1650 fs/ext4/inode.c:544 ext4_getblk+0xad/0x520 fs/ext4/inode.c:825 ext4_bread+0x7c/0x380 fs/ext4/inode.c:875 ext4_append+0x153/0x360 fs/ext4/namei.c:67 ext4_init_new_dir fs/ext4/namei.c:2755 [inline] ext4_mkdir+0x5bc/0xdc0 fs/ext4/namei.c:2800 vfs_mkdir+0x419/0x690 fs/namei.c:3625 do_mkdirat+0x21e/0x280 fs/namei.c:3648 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 7250: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 ext4_ext_map_blocks+0x8b7/0x3710 fs/ext4/extents.c:4319 ext4_map_blocks+0xcd3/0x1650 fs/ext4/inode.c:544 ext4_getblk+0xad/0x520 fs/ext4/inode.c:825 ext4_bread+0x7c/0x380 fs/ext4/inode.c:875 ext4_append+0x153/0x360 fs/ext4/namei.c:67 ext4_init_new_dir fs/ext4/namei.c:2755 [inline] ext4_mkdir+0x5bc/0xdc0 fs/ext4/namei.c:2800 vfs_mkdir+0x419/0x690 fs/namei.c:3625 do_mkdirat+0x21e/0x280 fs/namei.c:3648 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880a8221700 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 28 bytes inside of 96-byte region [ffff8880a8221700, ffff8880a8221760) The buggy address belongs to the page: page:ffffea0002a08840 refcount:1 mapcount:0 mapping:00000000661df321 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002999dc8 ffffea000253b6c8 ffff8880aa000540 raw: 0000000000000000 ffff8880a8221000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a8221600: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880a8221680: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc >ffff8880a8221700: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8880a8221780: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880a8221800: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc 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