[syslinux] Re: Problems with loading ramdisk under SYSLINUX 3.05
H. Peter Anvin
hpa at zytor.com
Sun Jan 9 18:43:40 PST 2005
Petr Vandrovec wrote:
> one of FreeDOS developers pointed out (in
> that FreeDOS does not work under VMware when using ISOLINUX 3.0x. After
> looking at their ISO image I downloaded syslinux-3.05, and there seems
> to be bad bug:
> You have this in kernel.inc:
> su_code32start resd 1 ; 0214 Start of code loaded high
> su_ramdiskat resd 1 ; 0218 Start of initial ramdisk
> su_ramdisklen equ $ ; Length of initial ramdisk
> su_bsklugeoffs resw 1 ; 0220
> su_bsklugeseg resw 1 ; 0222
> su_heapend resw 1 ; 0224
> su_pad1 resw 1 ; 0226
> su_cmd_line_ptr resd 1 ; 0228
> su_ramdisk_max resd 1 ; 022C
> But this puts su_ramdisklen at same address as su_bsklugeoffs, and so
> all items after su_ramdisklen are 4 bytes off!
> Due to this when memdisk from their ISO is loaded, runkernel.inc looks
> at su_cmd_line_ptr instead of at su_ramdisk_max, finds 0 there, and so
> loads image at 0 - 0x5A000 = 0xFFFA6000. But there is no ram at
> 0xFFFA6000, and so it does not quite work.
> So in addition to the fixing su_ramdisklen in kernel.inc it would be
> nice if you could verify whether su_ramdisk_max is not smaller than
> su_ramdisklen, and refuse to load ramdisk when such situation happens.
Well, I actually have a check like that, but this fooled that check too.
*SIGH* so much for thinking I pushed out a known set of changes with 3.05.
What's getting pretty clear is that I can't be relied on to do proper
testing by myself. I could really use a set of formal QA volunteers.
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