Hi all,
the Oops I reported earlier today, may be related to a problem of the
GNU C compiler, but I do not know MIPS assembly, so I ask for help.
Call Trace of the original oops:
> [<ffffffff802460b0>] sr_drive_status+0x50/0xe8
> [<ffffffff8024bb84>] cdrom_ioctl+0x5f4/0x1208
> [<ffffffff80245c6c>] sr_block_ioctl+0x64/0xe8
> [<ffffffff801ad8bc>] compat_blkdev_ioctl+0x7cc/0x18e0
> [<ffffffff800d1870>] do_open+0x98/0x310
> [<ffffffff800d1d60>] blkdev_open+0x0/0xc0
> [<ffffffff800d1da8>] blkdev_open+0x48/0xc0
> [<ffffffff8009c444>] __dentry_open+0x114/0x2e0
> [<ffffffff8009c740>] do_filp_open+0x48/0x58
> [<ffffffff8009c740>] do_filp_open+0x48/0x58
> [<ffffffff800def8c>] compat_sys_ioctl+0xf4/0x440
> [<ffffffff80019154>] handle_sys+0x114/0x130
> [<ffffffff8001fcf3>] fpu_emulator_cop1Handler+0x362/0x2270
sr_drive_status+0x50 is, in decimal, sr_drive_status+80
The gdb disassable the code as this:
(gdb) disassemble sr_drive_status+0x50
Dump of assembler code for function sr_drive_status:
0xffffffff80246060 <sr_drive_status+0>: daddiu sp,sp,-32
0xffffffff80246064 <sr_drive_status+4>: lui v0,0x7fff
0xffffffff80246068 <sr_drive_status+8>: sd s0,16(sp)
0xffffffff8024606c <sr_drive_status+12>: sd ra,24(sp)
0xffffffff80246070 <sr_drive_status+16>: ori v0,v0,0xffff
0xffffffff80246074 <sr_drive_status+20>: move s0,a0
0xffffffff80246078 <sr_drive_status+24>: bne a1,v0,0xffffffff802460e8 <sr_drive_status+136>
0xffffffff8024607c <sr_drive_status+28>: ld v1,24(a0)
0xffffffff80246080 <sr_drive_status+32>: ld a0,16(v1)
0xffffffff80246084 <sr_drive_status+36>: jal 0xffffffff80244c70 <sr_test_unit_ready>
0xffffffff80246088 <sr_drive_status+40>: daddiu a1,sp,4
0xffffffff8024608c <sr_drive_status+44>: bnez v0,0xffffffff802460a8 <sr_drive_status+72>
0xffffffff80246090 <sr_drive_status+48>: move a0,s0
0xffffffff80246094 <sr_drive_status+52>: li v0,4
0xffffffff80246098 <sr_drive_status+56>: ld ra,24(sp)
0xffffffff8024609c <sr_drive_status+60>: ld s0,16(sp)
0xffffffff802460a0 <sr_drive_status+64>: jr ra
0xffffffff802460a4 <sr_drive_status+68>: daddiu sp,sp,32
0xffffffff802460a8 <sr_drive_status+72>: jal 0xffffffff8024c838 <cdrom_get_media_event>
0xffffffff802460ac <sr_drive_status+76>: move a1,sp
0xffffffff802460b0 <sr_drive_status+80>: bnez v0,0xffffffff802460fc <sr_drive_status+156>
0xffffffff802460b4 <sr_drive_status+84>: lhu v0,0(sp)
0xffffffff802460b8 <sr_drive_status+88>: sll v0,v0,0x0
0xffffffff802460bc <sr_drive_status+92>: andi v0,v0,0xff
0xffffffff802460c0 <sr_drive_status+96>: andi v1,v0,0x2
0xffffffff802460c4 <sr_drive_status+100>: bnez v1,0xffffffff80246094 <sr_drive_status+52>
0xffffffff802460c8 <sr_drive_status+104>: andi v0,v0,0x1
0xffffffff802460cc <sr_drive_status+108>: beqz v0,0xffffffff80246098 <sr_drive_status+56>
0xffffffff802460d0 <sr_drive_status+112>: li v0,1
0xffffffff802460d4 <sr_drive_status+116>: ld ra,24(sp)
then, I changed the code in sr_drive_status, adding the printk line, as
shown below:
int sr_drive_status(struct cdrom_device_info *cdi, int slot)
{
struct scsi_cd *cd = cdi->handle;
struct scsi_sense_hdr sshdr;
struct media_event_desc med;
if (CDSL_CURRENT != slot) {
/* we have no changer support */
return -EINVAL;
}
if (0 == sr_test_unit_ready(cd->device, &sshdr))
return CDS_DISC_OK;
printk(KERN_INFO "sr_drive_status() cdi=0x%p, cd=0x%p\n", cdi, cd);
if (!cdrom_get_media_event(cdi, &med)) {
if (med.media_present)
return CDS_DISC_OK;
[...]
and now, I cannot reproduce any oops.
The new assembly code is:
0xffffffff80246060 <sr_drive_status+0>: daddiu sp,sp,-48
0xffffffff80246064 <sr_drive_status+4>: lui v0,0x7fff
0xffffffff80246068 <sr_drive_status+8>: sd s0,16(sp)
0xffffffff8024606c <sr_drive_status+12>: sd ra,32(sp)
0xffffffff80246070 <sr_drive_status+16>: sd s1,24(sp)
0xffffffff80246074 <sr_drive_status+20>: ori v0,v0,0xffff
0xffffffff80246078 <sr_drive_status+24>: move s0,a0
0xffffffff8024607c <sr_drive_status+28>: bne a1,v0,0xffffffff80246108 <sr_drive_status+168>
0xffffffff80246080 <sr_drive_status+32>: ld s1,24(a0)
0xffffffff80246084 <sr_drive_status+36>: ld a0,16(s1)
0xffffffff80246088 <sr_drive_status+40>: jal 0xffffffff80244c70 <sr_test_unit_ready>
0xffffffff8024608c <sr_drive_status+44>: daddiu a1,sp,4
0xffffffff80246090 <sr_drive_status+48>: bnez v0,0xffffffff802460b0 <sr_drive_status+80>
0xffffffff80246094 <sr_drive_status+52>: lui a0,0x803c
0xffffffff80246098 <sr_drive_status+56>: li v0,4
0xffffffff8024609c <sr_drive_status+60>: ld ra,32(sp)
0xffffffff802460a0 <sr_drive_status+64>: ld s1,24(sp)
0xffffffff802460a4 <sr_drive_status+68>: ld s0,16(sp)
0xffffffff802460a8 <sr_drive_status+72>: jr ra
0xffffffff802460ac <sr_drive_status+76>: daddiu sp,sp,48
0xffffffff802460b0 <sr_drive_status+80>: daddiu a0,a0,-4560
0xffffffff802460b4 <sr_drive_status+84>: move a1,s0
0xffffffff802460b8 <sr_drive_status+88>: jal 0xffffffff80032ba8 <printk>
0xffffffff802460bc <sr_drive_status+92>: move a2,s1
0xffffffff802460c0 <sr_drive_status+96>: move a0,s0
0xffffffff802460c4 <sr_drive_status+100>: jal 0xffffffff8024c858 <cdrom_get_media_event>
0xffffffff802460c8 <sr_drive_status+104>: move a1,sp
0xffffffff802460cc <sr_drive_status+108>: bnez v0,0xffffffff80246120 <sr_drive_status+192>
0xffffffff802460d0 <sr_drive_status+112>: lhu v0,0(sp)
the gcc I am using in versione 4.1.2. Any help is really appreciated.
Thanks,
Giuseppe
