================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88808e886c11 by task syz-executor.1/13158 CPU: 0 PID: 13158 Comm: syz-executor.1 Not tainted 4.14.184-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+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1dc 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+0xa9/0x2b9 mm/kasan/report.c:393 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3bb/0x480 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x282/0x5b0 drivers/tty/vt/vt.c:363 redraw_screen+0x562/0x760 drivers/tty/vt/vt.c:705 vc_do_resize+0xbe0/0xde0 drivers/tty/vt/vt.c:967 vt_ioctl+0x1a64/0x1f20 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb19 RSP: 002b:00007f8b5747cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004f3580 RCX: 000000000045cb19 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000067e R14: 00000000004c9852 R15: 00007f8b5747d6d4 Allocated by task 26404: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15a/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2621 con_font_set drivers/tty/vt/vt.c:4182 [inline] con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4247 vt_ioctl+0x736/0x1f20 drivers/tty/vt/vt_ioctl.c:928 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 25087: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 kernfs_fop_release+0x10d/0x180 fs/kernfs/file.c:783 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb The buggy address belongs to the object at ffff88808e886ac0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 337 bytes inside of 512-byte region [ffff88808e886ac0, ffff88808e886cc0) The buggy address belongs to the page: page:ffffea00023a2180 count:1 mapcount:0 mapping:ffff88808e8860c0 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff88808e8860c0 0000000000000000 0000000100000006 raw: ffffea00024352e0 ffffea00024219e0 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808e886b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808e886b80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc >ffff88808e886c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88808e886c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808e886d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================