audit: type=1400 audit(1575798221.152:39): avc: denied { read } for pid=7966 comm="syz-executor905" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 ================================================================== 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+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880852ab508 by task syz-executor905/7994 CPU: 0 PID: 7994 Comm: syz-executor905 Not tainted 4.19.88-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 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+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x42b/0x4f0 drivers/video/fbdev/core/fbcon.c:1320 do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677 redraw_screen+0x602/0x8e0 drivers/tty/vt/vt.c:1013 fbcon_do_set_font+0x73a/0xa40 drivers/video/fbdev/core/fbcon.c:2583 fbcon_copy_font+0x12c/0x190 drivers/video/fbdev/core/fbcon.c:2598 con_font_copy drivers/tty/vt/vt.c:4548 [inline] con_font_op+0x69a/0x1250 drivers/tty/vt/vt.c:4563 vt_ioctl+0x1784/0x2530 drivers/tty/vt/vt_ioctl.c:965 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x447839 Code: e8 3c e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 ab 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3ec94e4d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006ddc88 RCX: 0000000000447839 RDX: 0000000020000180 RSI: 0000000000004b72 RDI: 0000000000000003 RBP: 00000000006ddc80 R08: 00007f3ec94e5700 R09: 0000000000000000 R10: 00007f3ec94e5700 R11: 0000000000000246 R12: 00000000006ddc8c R13: 0000000000000000 R14: 00000000f72a8fce R15: 0000000000000001 Allocated by task 7974: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15d/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] fbcon_set_font+0x32d/0x860 drivers/video/fbdev/core/fbcon.c:2641 con_font_set drivers/tty/vt/vt.c:4492 [inline] con_font_op+0xe18/0x1250 drivers/tty/vt/vt.c:4557 vt_ioctl+0xd2e/0x2530 drivers/tty/vt/vt_ioctl.c:913 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/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 ffff8880852aad00 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 8 bytes to the right of 2048-byte region [ffff8880852aad00, ffff8880852ab500) The buggy address belongs to the page: page:ffffea000214aa80 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea00024e0308 ffffea000258de08 ffff88812c31cc40 raw: 0000000000000000 ffff8880852aa480 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880852ab400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880852ab480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880852ab500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880852ab580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880852ab600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================