================================================================== BUG: KASAN: slab-out-of-bounds in vcs_read_buf drivers/tty/vt/vc_screen.c:357 [inline] BUG: KASAN: slab-out-of-bounds in vcs_read+0xaa7/0xb40 drivers/tty/vt/vc_screen.c:449 Write of size 2 at addr ffff888056577000 by task syz-executor.5/17449 CPU: 1 PID: 17449 Comm: syz-executor.5 Not tainted 5.9.0-rc1-next-20200821-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 vcs_read_buf drivers/tty/vt/vc_screen.c:357 [inline] vcs_read+0xaa7/0xb40 drivers/tty/vt/vc_screen.c:449 do_loop_readv_writev fs/read_write.c:734 [inline] do_loop_readv_writev fs/read_write.c:721 [inline] do_iter_read+0x48e/0x6e0 fs/read_write.c:955 vfs_readv+0xe5/0x150 fs/read_write.c:1073 do_preadv fs/read_write.c:1165 [inline] __do_sys_preadv fs/read_write.c:1215 [inline] __se_sys_preadv fs/read_write.c:1210 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1210 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d579 Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f68ec55ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000025780 RCX: 000000000045d579 RDX: 0000000000000006 RSI: 0000000020001b00 RDI: 0000000000000005 RBP: 000000000118cf90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffcb87d06ff R14: 00007f68ec55f9c0 R15: 000000000118cf4c Allocated by task 6883: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:517 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 dup_fd+0x89/0xc90 fs/file.c:293 copy_files kernel/fork.c:1459 [inline] copy_process+0x1d99/0x6920 kernel/fork.c:2056 _do_fork+0xe8/0xb10 kernel/fork.c:2427 __do_sys_clone+0xc8/0x110 kernel/fork.c:2544 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff888056577040 which belongs to the cache files_cache of size 832 The buggy address is located 64 bytes to the left of 832-byte region [ffff888056577040, ffff888056577380) The buggy address belongs to the page: page:0000000016ded5e8 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880565777c0 pfn:0x56577 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002892a88 ffffea0002a09188 ffff88821bc47500 raw: ffff8880565777c0 ffff888056577040 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888056576f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888056576f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888056577000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff888056577080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888056577100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================