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BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
BUG: KASAN: slab-out-of-bounds in fb_pad_aligned_buffer+0x52d/0x5b0 drivers/video/fbdev/core/fbmem.c:116
Read of size 1 at addr ffff888057c3c810 by task syz-executor.0/4888

CPU: 0 PID: 4888 Comm: syz-executor.0 Not tainted 5.6.0-rc6-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+0x1e9/0x30e lib/dump_stack.c:118
 print_address_description+0x74/0x5c0 mm/kasan/report.c:374
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
 kasan_report+0x25/0x50 mm/kasan/common.c:641
 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
 fb_pad_aligned_buffer+0x52d/0x5b0 drivers/video/fbdev/core/fbmem.c:116
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:99 [inline]
 bit_putcs+0x1608/0x1bf0 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x790/0xaf0 drivers/video/fbdev/core/fbcon.c:1360
 do_update_region+0x2bf/0x620 drivers/tty/vt/vt.c:667
 update_region+0x1c7/0x8f0 drivers/tty/vt/vt.c:695
 vcs_write+0x774/0xc90 drivers/tty/vt/vc_screen.c:623
 do_loop_readv_writev fs/read_write.c:717 [inline]
 do_iter_write+0x426/0x570 fs/read_write.c:1000
 vfs_writev fs/read_write.c:1071 [inline]
 do_writev+0x239/0x490 fs/read_write.c:1114
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
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:00007f2288a16c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f2288a176d4 RCX: 000000000045c849
RDX: 0000000000000001 RSI: 0000000020000300 RDI: 0000000000000003
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000d12 R14: 00000000004cb19d R15: 000000000076bf0c

Allocated by task 9709:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x24b/0x330 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2670
 con_font_set drivers/tty/vt/vt.c:4547 [inline]
 con_font_op+0xeb9/0x1620 drivers/tty/vt/vt.c:4612
 vt_ioctl+0x23b7/0x3a30 drivers/tty/vt/vt_ioctl.c:970
 tty_ioctl+0xee6/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl fs/ioctl.c:763 [inline]
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8633:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x7e4/0x1080 kernel/rcu/tree.c:2410
 __do_softirq+0x268/0x7c5 kernel/softirq.c:292

The buggy address belongs to the object at ffff888057c38000
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 2064 bytes to the right of
 16384-byte region [ffff888057c38000, ffff888057c3c000)
The buggy address belongs to the page:
page:ffffea00015f0e00 refcount:1 mapcount:0 mapping:ffff8880aa402380 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea000160c608 ffffea0001526608 ffff8880aa402380
raw: 0000000000000000 ffff888057c38000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888057c3c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888057c3c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888057c3c800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888057c3c880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888057c3c900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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