Re: ALERT! Stay away from patched gcc's (was Re: 2.0.22 will be the last version)

Henrik Storner (storner@osiris.ping.dk)
Sat, 28 Sep 1996 23:54:16 +0200


In linux.kernel torvalds@cs.helsinki.fi writes:

>On Thu, 26 Sep 1996, Dr. Werner Fink wrote:
>>
>> Hmm --- my system (asus sp3g, ncr53c810 on board, amd5x86-P75, 1G SCSI-Disk,
>> SCSI-CDROM) is not able to boot 2.0.21 nor 2.0.20.
>> Note: 2.0.0 up to 2.0.18 boots without any problem and 2.0.18 is really
>> stable. All kernels are optimized for i486 and 53c7,8xx is used.

>Ok, I asked Werner to send me a disassembly of the affected function, and he
>definitely had some bad code produced by his compiler for the new inline
>assembly code to handle semaphores.
[snip]
>There is at least _one_ reasonably recent version of gcc out there that
>provably produces bad code when it comes to inline asm register clobbers, and
>I'd ask people to take a hard look at their compiler if they don't have a
>unpatched gcc. It looks like the standard gcc's are ok, but I wonder about
>gcc-2.7.2.1 (which reportedly also fixes the strength-reduce bug, and if they
>used the same bugfix as Werners version did, it may be suspect).

Just for the record, I am running 2.0.21 compiled with 2.7.2.1 on a
near-identical system to Werner Fink's: AMD 5x83-133, asus pvi-486sp3,
ncr 53c810, 1 Gb Conner SCSI disk and SCSI cd-rom. So far it's been up
three days without problems.

I have been using the 2.7.2.l3 un-official snapshot (by H.J.Lu) for a
while, also without problems, but recently upgraded to the official
2.7.2.1.

-- 
Henrik Storner                     | "Life is like a 10 speed bicycle.
storner@osiris.ping.dk             |  Most of us have gears we never use."
http://eolicom.olicom.dk/~storner/ |                        C. Schultz