================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:674 [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+0xbaf/0xd10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88809aac1402 by task syz-executor.4/15770 CPU: 1 PID: 15770 Comm: syz-executor.4 Not tainted 4.19.143-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+0x1fc/0x2fe lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load1_noabort+0x88/0x90 mm/kasan/report.c:430 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xbaf/0xd10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x336/0x4f0 drivers/video/fbdev/core/fbcon.c:1323 con_flush drivers/tty/vt/vt.c:2559 [inline] do_con_write+0xbcd/0x1d90 drivers/tty/vt/vt.c:2809 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3145 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x3c0/0xff0 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x496/0x810 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x770 fs/read_write.c:485 __kernel_write+0x109/0x370 fs/read_write.c:506 write_pipe_buf+0x153/0x1f0 fs/splice.c:798 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x389/0x800 fs/splice.c:627 splice_from_pipe fs/splice.c:662 [inline] default_file_splice_write+0xd8/0x180 fs/splice.c:810 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x115/0x160 fs/splice.c:1025 splice_direct_to_actor+0x33f/0x8d0 fs/splice.c:980 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d5b9 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:00007f7d76d84c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000027980 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000a808 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffc00fdad4f R14: 00007f7d76d859c0 R15: 000000000118cf4c Allocated by task 8029: __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15a/0x3c0 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] fbcon_set_font+0x34f/0x8a0 drivers/video/fbdev/core/fbcon.c:2665 con_font_set drivers/tty/vt/vt.c:4537 [inline] con_font_op+0xd02/0x10e0 drivers/tty/vt/vt.c:4602 vt_ioctl+0x116d/0x2580 drivers/tty/vt/vt_ioctl.c:938 tty_ioctl+0x5b0/0x15c0 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff88809aac12c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 322 bytes inside of 512-byte region [ffff88809aac12c0, ffff88809aac14c0) The buggy address belongs to the page: page:ffffea00026ab040 count:1 mapcount:0 mapping:ffff88812c39c940 index:0xffff88809aac1040 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea0002a3e388 ffffea0002259948 ffff88812c39c940 raw: ffff88809aac1040 ffff88809aac1040 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809aac1300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809aac1380: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc >ffff88809aac1400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809aac1480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809aac1500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ================================================================== ptrace attach of "/root/syz-executor.1"[15772] was attempted by "/root/syz-executor.1"[15774]