Hello,

syzbot found the following crash on:

HEAD commit: 6794862a Merge tag 'for-5.5-rc1-kconfig-tag' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17f407f2e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=79f79de2a27d3e3d dashboard link: https://syzkaller.appspot.com/bug?extid=26dc38a00dc05118a4e6 compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+26dc38a00dc05118a4e6@syzkaller.appspotmail.com

================================================================== BUG: KASAN: vmalloc-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x117f/0x1240 drivers/video/fbdev/core/sysimgblt.c:275 Write of size 4 at addr ffffc90008de1000 by task syz-executor.3/19698

CPU: 0 PID: 19698 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_store4_noabort+0x17/0x20 mm/kasan/generic_report.c:139 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] sys_imageblit+0x117f/0x1240 drivers/video/fbdev/core/sysimgblt.c:275 drm_fb_helper_sys_imageblit+0x21/0x180 drivers/gpu/drm/drm_fb_helper.c:768 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline] bit_putcs+0x9a3/0xf10 drivers/video/fbdev/core/bitblit.c:188 fbcon_putcs+0x33c/0x3e0 drivers/video/fbdev/core/fbcon.c:1353 do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677 invert_screen+0x2da/0x650 drivers/tty/vt/vt.c:794 highlight drivers/tty/vt/selection.c:53 [inline] clear_selection drivers/tty/vt/selection.c:81 [inline] clear_selection+0x59/0x70 drivers/tty/vt/selection.c:77 vc_do_resize+0x1163/0x1460 drivers/tty/vt/vt.c:1200 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1304 fbcon_do_set_font+0x4a6/0x960 drivers/video/fbdev/core/fbcon.c:2599 fbcon_set_font+0x72e/0x860 drivers/video/fbdev/core/fbcon.c:2696 con_font_set drivers/tty/vt/vt.c:4538 [inline] con_font_op+0xe30/0x1270 drivers/tty/vt/vt.c:4603 vt_ioctl+0xd2e/0x26d0 drivers/tty/vt/vt_ioctl.c:913 tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a7c9 Code: bd b1 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 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fcfa0ba6c88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 000000000045a7c9 RDX: 0000000020000140 RSI: 0000000000004b61 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcfa0ba76d4 R13: 00000000004ab60f R14: 00000000006ede60 R15: 00000000ffffffff

Memory state around the buggy address: ffffc90008de0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90008de0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

ffffc90008de1000: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9

^ ffffc90008de1080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 ffffc90008de1100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 ==================================================================

--- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.