Hello,
Triggered this while fuzzing v3.17-rc1-51-g372b1db with Trinity.
Tommi
[drm:drm_mode_legacy_fb_format] *ERROR* bad bpp, assuming x8r8g8b8 pixel format divide error: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 0 PID: 2854 Comm: trinity-c7 Not tainted 3.17.0-rc1+ #14 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff88003926cac0 ti: ffff8800356b4000 task.ti: ffff8800356b4000 RIP: 0010:[<ffffffff816688e3>] [<ffffffff816688e3>] drm_mode_create_dumb_ioctl+0x53/0xa0 RSP: 0018:ffff8800356b7dc0 EFLAGS: 00010246 RAX: 00000000ffffffff RBX: ffff88003545da68 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8800356b7e18 RDI: ffff88003d5c67b0 RBP: ffff8800356b7dc8 R08: 0000000000000000 R09: 00000000ffffffff R10: 00000000ffffffff R11: ffffffff817f6d30 R12: 00000000000000b2 R13: fffffffffffffff2 R14: ffff88003d5c67b0 R15: ffff88003545da68 FS: 00007f06208fa700(0000) GS:ffff88003fa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001903108 CR3: 0000000036efa000 CR4: 00000000000006f0 Stack: ffff8800356b7e18 ffff8800356b7ec8 ffffffff8165ac60 ffff8800356b7df8 ffff8800356b7e18 ffff8800356b7e18 ffffffff824e1440 0000000000d52000 0000000000000020 00000000c02064b2 00000000fffffff2 ffffffffffffffff Call Trace: [<ffffffff8165ac60>] drm_ioctl+0x3b0/0x640 [<ffffffff814b81b8>] ? avc_has_perm+0x218/0x2f0 [<ffffffff814b7fc0>] ? avc_has_perm+0x20/0x2f0 [<ffffffff81170bb8>] ? sched_clock_cpu+0xa8/0xf0 [<ffffffff812922a0>] do_vfs_ioctl+0x4d0/0x510 [<ffffffff814ba745>] ? selinux_file_ioctl+0xf5/0x100 [<ffffffff8129232e>] SyS_ioctl+0x4e/0x80 [<ffffffff822b10e9>] system_call_fastpath+0x16/0x1b Code: 55 41 b9 ff ff ff ff 41 83 c0 07 44 89 c8 41 c1 e8 03 48 89 e5 53 48 89 d3 31 d2 f7 f1 41 39 c0 77 46 41 0f af c8 31 d2 44 89 c8 <f7> f1 41 39 c2 77 36 41 0f af ca b8 ea ff ff ff 81 c1 ff 0f 00 RIP [<ffffffff816688e3>] drm_mode_create_dumb_ioctl+0x53/0xa0 RSP <ffff8800356b7dc0> ---[ end trace 6919129b71d9bf98 ]--- [drm:drm_mode_legacy_fb_format] *ERROR* bad bpp, assuming x8r8g8b8 pixel format
(gdb) list *0xffffffff816688e3 0xffffffff816688e3 is in drm_mode_create_dumb_ioctl (drivers/gpu/drm/drm_crtc.c:4703). 4698 /* overflow checks for 32bit size calculations */ 4699 cpp = DIV_ROUND_UP(args->bpp, 8); 4700 if (cpp > 0xffffffffU / args->width) 4701 return -EINVAL; 4702 stride = cpp * args->width; 4703 if (args->height > 0xffffffffU / stride) 4704 return -EINVAL; 4705 4706 /* test for wrap-around */ 4707 size = args->height * stride; (gdb) disassemble drm_mode_create_dumb_ioctl Dump of assembler code for function drm_mode_create_dumb_ioctl: 0xffffffff81668890 <+0>: mov 0x20(%rdi),%rax 0xffffffff81668894 <+4>: mov 0x160(%rax),%r11 0xffffffff8166889b <+11>: test %r11,%r11 0xffffffff8166889e <+14>: je 0xffffffff8166890f <drm_mode_create_dumb_ioctl+127> 0xffffffff816688a0 <+16>: mov 0x4(%rsi),%ecx 0xffffffff816688a3 <+19>: test %ecx,%ecx 0xffffffff816688a5 <+21>: je 0xffffffff81668918 <drm_mode_create_dumb_ioctl+136> 0xffffffff816688a7 <+23>: mov (%rsi),%r10d 0xffffffff816688aa <+26>: test %r10d,%r10d 0xffffffff816688ad <+29>: je 0xffffffff81668918 <drm_mode_create_dumb_ioctl+136> 0xffffffff816688af <+31>: mov 0x8(%rsi),%r8d 0xffffffff816688b3 <+35>: test %r8d,%r8d 0xffffffff816688b6 <+38>: je 0xffffffff81668918 <drm_mode_create_dumb_ioctl+136> 0xffffffff816688b8 <+40>: push %rbp 0xffffffff816688b9 <+41>: mov $0xffffffff,%r9d 0xffffffff816688bf <+47>: add $0x7,%r8d 0xffffffff816688c3 <+51>: mov %r9d,%eax 0xffffffff816688c6 <+54>: shr $0x3,%r8d 0xffffffff816688ca <+58>: mov %rsp,%rbp 0xffffffff816688cd <+61>: push %rbx 0xffffffff816688ce <+62>: mov %rdx,%rbx 0xffffffff816688d1 <+65>: xor %edx,%edx 0xffffffff816688d3 <+67>: div %ecx 0xffffffff816688d5 <+69>: cmp %eax,%r8d 0xffffffff816688d8 <+72>: ja 0xffffffff81668920 <drm_mode_create_dumb_ioctl+144> 0xffffffff816688da <+74>: imul %r8d,%ecx 0xffffffff816688de <+78>: xor %edx,%edx 0xffffffff816688e0 <+80>: mov %r9d,%eax 0xffffffff816688e3 <+83>: div %ecx 0xffffffff816688e5 <+85>: cmp %eax,%r10d 0xffffffff816688e8 <+88>: ja 0xffffffff81668920 <drm_mode_create_dumb_ioctl+144> 0xffffffff816688ea <+90>: imul %r10d,%ecx 0xffffffff816688ee <+94>: mov $0xffffffea,%eax 0xffffffff816688f3 <+99>: add $0xfff,%ecx 0xffffffff816688f9 <+105>: and $0xfffff000,%ecx 0xffffffff816688ff <+111>: je 0xffffffff81668928 <drm_mode_create_dumb_ioctl+152> 0xffffffff81668901 <+113>: mov %rsi,%rdx 0xffffffff81668904 <+116>: mov %rdi,%rsi 0xffffffff81668907 <+119>: mov %rbx,%rdi 0xffffffff8166890a <+122>: callq *%r11 0xffffffff8166890d <+125>: jmp 0xffffffff81668928 <drm_mode_create_dumb_ioctl+152> 0xffffffff8166890f <+127>: mov $0xffffffda,%eax 0xffffffff81668914 <+132>: retq 0xffffffff81668915 <+133>: nopl (%rax) 0xffffffff81668918 <+136>: mov $0xffffffea,%eax 0xffffffff8166891d <+141>: retq 0xffffffff8166891e <+142>: xchg %ax,%ax 0xffffffff81668920 <+144>: mov $0xffffffea,%eax 0xffffffff81668925 <+149>: nopl (%rax) 0xffffffff81668928 <+152>: pop %rbx 0xffffffff81668929 <+153>: pop %rbp 0xffffffff8166892a <+154>: retq End of assembler dump. (gdb)