bin/175086: 9.1 does not boot from GPT partition that can have more that 128 partition entries (worked under 7.4-STABLE, bug in sys/boot/common/gpt.c)

[Andre Albsmeier]

>Number:         175086
>Category:       bin
>Synopsis:       9.1 does not boot from GPT partition that can have more that 128 partition entries (worked under 7.4-STABLE, bug in sys/boot/common/gpt.c)
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jan 07 07:00:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Andre Albsmeier
>Release:        FreeBSD 9.1-PRERELEASE i386
>Organization:
>Environment:

System: FreeBSD 9.1-PRERELEASE

>Description:

Booting from a GPT partitioned disk that can have more
than 128 parition entries (e.g. 248 in this case)
fails under 9.1 but worked under 7.4.

This is due to a test that was introduced in sys/boot/common/gpt.c:

...
#define MAXTBLENTS      128
...
        if (bcmp(hdr->hdr_sig, GPT_HDR_SIG, sizeof(hdr->hdr_sig)) != 0 ||
            hdr->hdr_lba_self != hdrlba || hdr->hdr_revision < 0x00010000 ||
            hdr->hdr_entsz < sizeof(struct gpt_ent) ||
            hdr->hdr_entries > MAXTBLENTS || DEV_BSIZE % hdr->hdr_entsz != 0) {
                printf("%s: invalid %s GPT header\n", BOOTPROG, which);
                return (-1);
        }

>How-To-Repeat:

Create a disk using

gpart create -s gpt -n 248 $disk

and add bootcode and system to it. Add some delay into gptinit()
of sys/boot/i386/gptboot/gptboot.c so you can read the error
messages before reset occurs:

invalid primary GPT header
invalid backup GPT header
unable to load GPT

>Fix:

The check should be removed since a GPT header with more than
128 possible parition entries is not invalid and can legally
be created with gpart.
>Release-Note:
>Audit-Trail:
>Unformatted: