Hello,
syzbot found the following issue on:
HEAD commit: 4fa640dc Merge tag 'vfio-v5.8-rc7' of git://github.com/awi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17ec2d58900000 kernel config: https://syzkaller.appspot.com/x/.config?x=575b381064b1cba2 dashboard link: https://syzkaller.appspot.com/bug?extid=ba5bd977df7bb87862c4 compiler: gcc (GCC) 10.1.0-syz 20200507 userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ba5bd977df7bb87862c4@syzkaller.appspotmail.com
================================================================== BUG: KASAN: stack-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] BUG: KASAN: stack-out-of-bounds in sys_imageblit+0x117f/0x1290 drivers/video/fbdev/core/sysimgblt.c:275 Write of size 4 at addr ffffc900097d7d90 by task syz-executor.1/11925
CPU: 1 PID: 11925 Comm: syz-executor.1 Not tainted 5.8.0-rc6-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] sys_imageblit+0x117f/0x1290 drivers/video/fbdev/core/sysimgblt.c:275 drm_fb_helper_sys_imageblit+0x1c/0x180 drivers/gpu/drm/drm_fb_helper.c:763 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:188 fbcon_putcs+0x33c/0x3f0 drivers/video/fbdev/core/fbcon.c:1362 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:683 invert_screen+0x1d4/0x600 drivers/tty/vt/vt.c:800 highlight drivers/tty/vt/selection.c:57 [inline] clear_selection drivers/tty/vt/selection.c:84 [inline] clear_selection+0x55/0x70 drivers/tty/vt/selection.c:80 vc_do_resize+0x1099/0x13f0 drivers/tty/vt/vt.c:1230 fbcon_do_set_font+0x4ad/0x950 drivers/video/fbdev/core/fbcon.c:2609 fbcon_set_font+0x767/0x8b0 drivers/video/fbdev/core/fbcon.c:2706 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 vt_compat_ioctl+0x168/0x6b0 drivers/tty/vt/vt_ioctl.c:1249 tty_compat_ioctl+0x19c/0x410 drivers/tty/tty_io.c:2847 __do_compat_sys_ioctl+0x1d3/0x230 fs/ioctl.c:847 do_syscall_32_irqs_on+0x3f/0x60 arch/x86/entry/common.c:428 __do_fast_syscall_32 arch/x86/entry/common.c:475 [inline] do_fast_syscall_32+0x7f/0x120 arch/x86/entry/common.c:503 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f48569 Code: Bad RIP value. RSP: 002b:00000000f5d430bc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004b61 RDX: 0000000020000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Memory state around the buggy address: ffffc900097d7c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc900097d7d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc900097d7d80: 00 00 f1 f1 f1 f1 00 00 f3 f3 00 00 00 00 00 00
^ ffffc900097d7e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc900097d7e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================
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