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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 ffff888090e62000 by task syz-executor.1/13161

CPU: 0 PID: 13161 Comm: syz-executor.1 Not tainted 5.9.0-rc2-next-20200824-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:00007fb0be6b5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000025780 RCX: 000000000045d579
RDX: 0000000000000006 RSI: 0000000020001b00 RDI: 0000000000000005
RBP: 000000000118cf90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffcb1a8f55f R14: 00007fb0be6b69c0 R15: 000000000118cf4c

Allocated by task 3907:
 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
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
 getname_flags fs/namei.c:2646 [inline]
 user_path_at_empty+0xa1/0x100 fs/namei.c:2646
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x14e/0x390 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3175 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 3907:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
 putname+0xe1/0x120 fs/namei.c:259
 filename_lookup+0x3b1/0x560 fs/namei.c:2376
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x14e/0x390 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3175 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 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 ffff888090e62840
 which belongs to the cache names_cache of size 4096
The buggy address is located 2112 bytes to the left of
 4096-byte region [ffff888090e62840, ffff888090e63840)
The buggy address belongs to the page:
page:00000000e2cfa8e9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x90e62
head:00000000e2cfa8e9 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0001375488 ffffea000138f888 ffff88821bc47a00
raw: 0000000000000000 ffff888090e62840 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888090e61f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888090e61f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888090e62000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888090e62080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888090e62100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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