KASAN: vmalloc-out-of-bounds Write in sys

KASAN: vmalloc-out-of-bounds Write in sys_imageblit
Status: upstream: reported C repro on 2019/12/10 16:38
Reported-by: syzbot+26dc38a00dc05118a4e6@syzkaller.appspotmail.com
First crash: 557d, last: 190d

Sample crash report:

==================================================================
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/0x1290 drivers/video/fbdev/core/sysimgblt.c:275
Write of size 4 at addr ffffc90009911000 by task syz-executor045/8761

CPU: 0 PID: 8761 Comm: syz-executor045 Not tainted 5.9.0-rc8-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+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x497 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:767
 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline]
 bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:188
 fbcon_putcs+0x35a/0x450 drivers/video/fbdev/core/fbcon.c:1308
 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:675
 redraw_screen+0x658/0x790 drivers/tty/vt/vt.c:1034
 fbcon_modechanged+0x593/0x6d0 drivers/video/fbdev/core/fbcon.c:2714
 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:2759
 do_fb_ioctl+0x62e/0x690 drivers/video/fbdev/core/fbmem.c:1106
 fb_compat_ioctl+0x17c/0xc30 drivers/video/fbdev/core/fbmem.c:1311
 __do_compat_sys_ioctl+0x1d3/0x230 fs/ioctl.c:842
 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline]
 __do_fast_syscall_32+0x60/0x90 arch/x86/entry/common.c:137
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:160
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f58549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f7f531dc EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004601
RDX: 0000000020000000 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:
 ffffc90009910f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90009910f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90009911000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90009911080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90009911100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (91):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info
ci-qemu-upstream-386	2020/10/07 07:41	upstream	c85fb28b	1880b4a9	.config	log	report	syz	C
ci-qemu-upstream	2020/06/11 23:34	upstream	435faf5c	5c25fdab	.config	log	report	syz
ci-qemu-upstream-386	2020/10/07 05:27	upstream	c85fb28b	1880b4a9	.config	log	report	syz
ci-qemu-upstream	2020/12/11 04:46	upstream	9fca90cf	f900b48c	.config	log	report			info
ci-qemu-upstream	2020/12/10 11:38	upstream	a2f5ea9e	2a55c22b	.config	log	report			info
ci-qemu-upstream	2020/12/10 10:07	upstream	a2f5ea9e	2a55c22b	.config	log	report			info
ci-qemu-upstream	2020/12/04 19:40	upstream	e87297fa	20366b87	.config	log	report			info
ci-qemu-upstream	2020/12/02 11:47	upstream	509a1542	eff43e99	.config	log	report			info
ci-qemu-upstream	2020/12/01 22:38	upstream	b6505459	07bfe8a5	.config	log	report			info
ci-qemu-upstream	2020/11/10 07:55	upstream	407ab579	cca87986	.config	log	report			info
ci-qemu-upstream	2020/11/10 02:54	upstream	407ab579	64069d48	.config	log	report			info
ci-qemu-upstream	2020/11/09 22:56	upstream	f8394f23	64069d48	.config	log	report			info
ci-qemu-upstream	2020/11/05 15:24	upstream	4ef8451b	64069d48	.config	log	report			info
ci-qemu-upstream	2020/10/23 19:14	upstream	0adc313c	2bb6666c	.config	log	report			info
ci-qemu-upstream	2020/09/11 07:49	upstream	fffe3ae0	adfb8b4e	.config	log	report
ci-qemu-upstream	2020/09/09 07:27	upstream	fffe3ae0	0ea7a887	.config	log	report
ci-qemu-upstream	2020/09/08 17:15	upstream	fffe3ae0	abf9ba4f	.config	log	report
ci-qemu-upstream	2020/09/04 23:53	upstream	fffe3ae0	abf9ba4f	.config	log	report
ci-qemu-upstream	2019/12/17 10:41	upstream	ea200dec	2b31345f	.config	log	report
ci-qemu-upstream	2019/12/10 15:24	upstream	6794862a	4b83c8fb	.config	log	report
ci-qemu-upstream-386	2020/12/11 22:50	upstream	94801e5c	bca53db9	.config	log	report			info
ci-qemu-upstream-386	2020/11/18 15:53	upstream	0fa8ee0d	09323409	.config	log	report			info
ci-qemu-upstream-386	2020/11/02 20:55	upstream	495023e4	f7362256	.config	log	report			info
ci-qemu-upstream-386	2020/10/27 22:18	upstream	ed8780e3	96e03c1c	.config	log	report			info
ci-qemu-upstream-386	2020/10/18 12:53	upstream	9d9af100	fea47c01	.config	log	report			info
ci-qemu-upstream-386	2020/10/18 01:42	upstream	9d9af100	fea47c01	.config	log	report			info
ci-qemu-upstream-386	2020/10/13 06:56	upstream	1e6d1d96	d32b0bbf	.config	log	report			info
ci-qemu-upstream-386	2020/10/13 02:00	upstream	1e6d1d96	d32b0bbf	.config	log	report			info
ci-qemu-upstream-386	2020/10/12 22:03	upstream	1e6d1d96	d32b0bbf	.config	log	report			info
ci-qemu-upstream-386	2020/10/11 19:35	upstream	3dd0130f	4a77ae0b	.config	log	report			info
ci-qemu-upstream-386	2020/10/11 15:52	upstream	da690031	4a77ae0b	.config	log	report			info
ci-qemu-upstream-386	2020/10/11 02:06	upstream	da690031	4a77ae0b	.config	log	report			info
ci-qemu-upstream-386	2020/10/09 22:33	upstream	8a5f78d9	93817d89	.config	log	report			info
ci-qemu-upstream-386	2020/10/09 10:30	upstream	583090b1	fa79ed2a	.config	log	report			info
ci-qemu-upstream-386	2020/10/08 21:12	upstream	3d006ee4	92390980	.config	log	report			info
ci-qemu-upstream-386	2020/10/08 11:01	upstream	c85fb28b	92390980	.config	log	report			info
ci-qemu-upstream-386	2020/10/07 11:25	upstream	c85fb28b	1880b4a9	.config	log	report			info
ci-qemu-upstream-386	2020/10/07 07:04	upstream	c85fb28b	1880b4a9	.config	log	report			info
ci-qemu-upstream-386	2020/10/07 04:04	upstream	c85fb28b	1880b4a9	.config	log	report			info
ci-qemu-upstream-386	2020/10/05 02:40	upstream	549738f1	5ef9c291	.config	log	report			info
ci-qemu-upstream-386	2020/10/04 14:29	upstream	22fbc037	5ef9c291	.config	log	report			info
ci-qemu-upstream-386	2020/10/04 03:00	upstream	22fbc037	1a3f9408	.config	log	report			info
ci-qemu-upstream-386	2020/09/30 06:51	upstream	02de58b2	8516f6d3	.config	log	report			info
ci-qemu-upstream-386	2020/09/28 22:41	upstream	a4d63c37	1b88c6d5	.config	log	report			info
ci-qemu-upstream-386	2020/09/06 15:12	upstream	dd9fb9bb	abf9ba4f	.config	log	report
ci-qemu-upstream-386	2020/09/04 04:40	upstream	e28f0104	abf9ba4f	.config	log	report
ci-qemu-upstream-386	2020/08/25 20:46	upstream	abb3438d	344da168	.config	log	report