Hello,
syzbot found the following issue on:
HEAD commit: fa55b7dcdc43 Linux 5.16-rc1 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15fe2569b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=6d3b8fd1977c1e73 dashboard link: https://syzkaller.appspot.com/bug?extid=14b0e8f3fd1612e35350 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 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+14b0e8f3fd1612e35350@syzkaller.appspotmail.com
524155 pages RAM 0 pages HighMem/MovableOnly 163742 pages reserved 0 pages cma reserved ================================================================== 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+0x12f4/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 Write of size 4 at addr ffffc90004631000 by task syz-executor.0/7913
CPU: 0 PID: 7913 Comm: syz-executor.0 Not tainted 5.16.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xf/0x320 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:433 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] sys_imageblit+0x12f4/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 drm_fb_helper_sys_imageblit drivers/gpu/drm/drm_fb_helper.c:794 [inline] drm_fbdev_fb_imageblit+0x15c/0x350 drivers/gpu/drm/drm_fb_helper.c:2282 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:124 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:173 fbcon_putcs+0x353/0x440 drivers/video/fbdev/core/fbcon.c:1277 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:676 redraw_screen+0x61f/0x740 drivers/tty/vt/vt.c:1035 fbcon_modechanged+0x58c/0x6c0 drivers/video/fbdev/core/fbcon.c:2182 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:2227 do_fb_ioctl+0x62e/0x690 drivers/video/fbdev/core/fbmem.c:1114 fb_compat_ioctl+0x17e/0x610 drivers/video/fbdev/core/fbmem.c:1313 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:972 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf6e67549 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 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f44615fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 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 </TASK>
Memory state around the buggy address: ffffc90004630f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90004630f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90004631000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^ ffffc90004631080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90004631100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
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syzbot has found a reproducer for the following issue on:
HEAD commit: 7fc5253f5a13 Add linux-next specific files for 20220120 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16385270700000 kernel config: https://syzkaller.appspot.com/x/.config?x=94e8da4df9ab6319 dashboard link: https://syzkaller.appspot.com/bug?extid=14b0e8f3fd1612e35350 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=155dde3db00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=125298e0700000
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+14b0e8f3fd1612e35350@syzkaller.appspotmail.com
BUG: unable to handle page fault for address: fffff520008b2208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 23ffed067 P4D 23ffed067 PUD 10db4067 PMD 1470c4067 PTE 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3595 Comm: syz-executor362 Not tainted 5.16.0-next-20220120-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x656/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 Code: 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b6 0c 00 00 8b 44 24 20 23 03 8b 5c 24 18 31 c3 48 89 e8 48 c1 e8 03 <42> 0f b6 14 38 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 RSP: 0018:ffffc90002a1f368 EFLAGS: 00010a02 RAX: 1ffff920008b2208 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff84257bf0 RDI: 0000000000000003 RBP: ffffc90004591040 R08: 000000000000001f R09: ffffffff84257a74 R10: ffffffff84257be1 R11: 0000000000000020 R12: 0000000000000007 R13: 00000000000003ef R14: ffff888146efc7e0 R15: dffffc0000000000 FS: 0000555555c5d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520008b2208 CR3: 0000000023b12000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> drm_fb_helper_sys_imageblit drivers/gpu/drm/drm_fb_helper.c:794 [inline] drm_fbdev_fb_imageblit+0x15c/0x350 drivers/gpu/drm/drm_fb_helper.c:2288 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:124 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:173 fbcon_putcs+0x353/0x440 drivers/video/fbdev/core/fbcon.c:1277 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:676 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+0xe6e/0x1180 drivers/tty/vt/vt.c:1257 fbcon_do_set_font+0x47a/0x760 drivers/video/fbdev/core/fbcon.c:1928 fbcon_set_font+0x817/0xa00 drivers/video/fbdev/core/fbcon.c:2014 con_font_set drivers/tty/vt/vt.c:4666 [inline] con_font_op+0x73a/0xc90 drivers/tty/vt/vt.c:4710 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x1e26/0x2b10 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0xbbd/0x1660 drivers/tty/tty_io.c:2778 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3bac0e1349 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffff160a718 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3bac0e1349 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000004 RBP: 00007f3bac0a51d0 R08: 000000000000000d R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3bac0a5260 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: CR2: fffff520008b2208 ---[ end trace 0000000000000000 ]--- RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline] RIP: 0010:sys_imageblit+0x656/0x1430 drivers/video/fbdev/core/sysimgblt.c:275 Code: 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b6 0c 00 00 8b 44 24 20 23 03 8b 5c 24 18 31 c3 48 89 e8 48 c1 e8 03 <42> 0f b6 14 38 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 RSP: 0018:ffffc90002a1f368 EFLAGS: 00010a02 RAX: 1ffff920008b2208 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff84257bf0 RDI: 0000000000000003 RBP: ffffc90004591040 R08: 000000000000001f R09: ffffffff84257a74 R10: ffffffff84257be1 R11: 0000000000000020 R12: 0000000000000007 R13: 00000000000003ef R14: ffff888146efc7e0 R15: dffffc0000000000 FS: 0000555555c5d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff520008b2208 CR3: 0000000023b12000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 14 38 adc $0x38,%al 2: 48 89 d8 mov %rbx,%rax 5: 83 e0 07 and $0x7,%eax 8: 83 c0 03 add $0x3,%eax b: 38 d0 cmp %dl,%al d: 7c 08 jl 0x17 f: 84 d2 test %dl,%dl 11: 0f 85 b6 0c 00 00 jne 0xccd 17: 8b 44 24 20 mov 0x20(%rsp),%eax 1b: 23 03 and (%rbx),%eax 1d: 8b 5c 24 18 mov 0x18(%rsp),%ebx 21: 31 c3 xor %eax,%ebx 23: 48 89 e8 mov %rbp,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 0f b6 14 38 movzbl (%rax,%r15,1),%edx <-- trapping instruction 2f: 48 89 e8 mov %rbp,%rax 32: 83 e0 07 and $0x7,%eax 35: 83 c0 03 add $0x3,%eax 38: 38 d0 cmp %dl,%al 3a: 7c 08 jl 0x44 3c: 84 d2 test %dl,%dl 3e: 0f .byte 0xf 3f: 85 .byte 0x85
syzbot has bisected this issue to:
commit 0499f419b76f94ede08304aad5851144813ac55c Author: Javier Martinez Canillas javierm@redhat.com Date: Mon Jan 10 09:56:25 2022 +0000
video: vga16fb: Only probe for EGA and VGA 16 color graphic cards
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14c71e37b00000 start commit: 7fc5253f5a13 Add linux-next specific files for 20220120 git tree: linux-next final oops: https://syzkaller.appspot.com/x/report.txt?x=16c71e37b00000 console output: https://syzkaller.appspot.com/x/log.txt?x=12c71e37b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=94e8da4df9ab6319 dashboard link: https://syzkaller.appspot.com/bug?extid=14b0e8f3fd1612e35350 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=155dde3db00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=125298e0700000
Reported-by: syzbot+14b0e8f3fd1612e35350@syzkaller.appspotmail.com Fixes: 0499f419b76f ("video: vga16fb: Only probe for EGA and VGA 16 color graphic cards")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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