audit: type=1400 audit(1594550334.661:8): avc: denied { execmem } for pid=6439 comm="syz-executor444" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process 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+0xbaf/0xd10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a0f818b0 by task syz-executor444/6439 CPU: 0 PID: 6439 Comm: syz-executor444 Not tainted 4.19.132-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 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:683 redraw_screen+0x5e1/0x870 drivers/tty/vt/vt.c:1031 vc_do_resize+0x1132/0x1440 drivers/tty/vt/vt.c:1317 vt_ioctl+0x1f74/0x24d0 drivers/tty/vt/vt_ioctl.c:901 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 RIP: 0033:0x4403a9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 db 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd6a7c56a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403a9 RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000004 RBP: 00000000006ca018 R08: 000000000000000d R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401c10 R13: 0000000000401ca0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6439: __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:2644 con_font_set drivers/tty/vt/vt.c:4529 [inline] con_font_op+0xd02/0x10e0 drivers/tty/vt/vt.c:4594 vt_ioctl+0x116d/0x24d0 drivers/tty/vt/vt_ioctl.c:928 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 24: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 free_tty_struct drivers/tty/tty_io.c:173 [inline] release_one_tty+0x2dd/0x3f0 drivers/tty/tty_io.c:1463 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x30b/0x410 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 The buggy address belongs to the object at ffff8880a0f81680 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 560 bytes inside of 1024-byte region [ffff8880a0f81680, ffff8880a0f81a80) The buggy address belongs to the page: page:ffffea000283e000 count:1 mapcount:0 mapping:ffff88812c39cac0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea00028db288 ffffea000282be08 ffff88812c39cac0 raw: 0000000000000000 ffff8880a0f80000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a0f81780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a0f81800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a0f81880: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a0f81900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a0f81980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================