================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [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+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a6d10230 by task syz-executor665/6810 CPU: 1 PID: 6810 Comm: syz-executor665 Not tainted 5.8.0-rc4-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x33c/0x3f0 drivers/video/fbdev/core/fbcon.c:1362 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:683 redraw_screen+0x64c/0x770 drivers/tty/vt/vt.c:1029 vc_do_resize+0x110e/0x13f0 drivers/tty/vt/vt.c:1314 vt_ioctl+0x2037/0x2670 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4403a9 Code: Bad RIP value. RSP: 002b:00007fffe534add8 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 6810: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x17a/0x340 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] fbcon_set_font+0x34f/0x8b0 drivers/video/fbdev/core/fbcon.c:2673 con_font_set drivers/tty/vt/vt.c:4571 [inline] con_font_op+0xd25/0x1110 drivers/tty/vt/vt.c:4636 vt_ioctl+0x1180/0x2670 drivers/tty/vt/vt_ioctl.c:928 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 1: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x103/0x2c0 mm/slab.c:3757 skb_free_head net/core/skbuff.c:590 [inline] skb_release_data+0x6d9/0x910 net/core/skbuff.c:610 skb_release_all net/core/skbuff.c:664 [inline] __kfree_skb net/core/skbuff.c:678 [inline] consume_skb net/core/skbuff.c:837 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:831 unix_stream_read_generic+0x16c9/0x1ae0 net/unix/af_unix.c:2416 unix_stream_recvmsg+0xb1/0xf0 net/unix/af_unix.c:2474 sock_recvmsg_nosec net/socket.c:886 [inline] sock_recvmsg net/socket.c:904 [inline] sock_recvmsg net/socket.c:900 [inline] ____sys_recvmsg+0x2c4/0x640 net/socket.c:2575 ___sys_recvmsg+0x127/0x200 net/socket.c:2617 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2651 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880a6d10000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 560 bytes inside of 1024-byte region [ffff8880a6d10000, ffff8880a6d10400) The buggy address belongs to the page: page:ffffea00029b4400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a6d10800 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029c9908 ffffea00026b8ec8 ffff8880aa000c40 raw: ffff8880a6d10800 ffff8880a6d10000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a6d10100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a6d10180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a6d10200: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a6d10280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a6d10300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================