================================================================== 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 ffff88809219e0e0 by task syz-executor.3/14649 CPU: 0 PID: 14649 Comm: syz-executor.3 Not tainted 4.19.139-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:2558 [inline] do_con_write+0xd0e/0x1d90 drivers/tty/vt/vt.c:2811 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3144 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: 0033:0x45d239 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:00007f89037f1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000026bc0 RCX: 000000000045d239 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 0800000080004103 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fff095f6f8f R14: 00007f89037f29c0 R15: 000000000118cf4c Allocated by task 3711: kmem_cache_alloc+0x122/0x370 mm/slab.c:3559 getname_flags+0xce/0x590 fs/namei.c:140 do_sys_open+0x26c/0x520 fs/open.c:1079 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 3711: __cache_free mm/slab.c:3503 [inline] kmem_cache_free+0x7f/0x260 mm/slab.c:3765 putname+0xe1/0x120 fs/namei.c:261 do_sys_open+0x2ba/0x520 fs/open.c:1094 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809219ebc0 which belongs to the cache names_cache of size 4096 The buggy address is located 2784 bytes to the left of 4096-byte region [ffff88809219ebc0, ffff88809219fbc0) The buggy address belongs to the page: page:ffffea0002486780 count:1 mapcount:0 mapping:ffff8880aa00ab40 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0001449608 ffffea000294eb08 ffff8880aa00ab40 raw: 0000000000000000 ffff88809219ebc0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809219df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809219e000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809219e080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809219e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809219e180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================