From: "Thomas Schmitt" <scdbackup@gmx.net>
To: bug-xorriso@gnu.org
Cc: 33639@debbugs.gnu.org
Subject: bug#33639: ISO installer image is broken on i686
Date: Sat, 08 Dec 2018 13:42:53 +0100 [thread overview]
Message-ID: <14249682530673393275@scdbackup.webframe.org> (raw)
In-Reply-To: <87k1klar3e.fsf@gnu.org>
Hi,
> https://alpha.gnu.org/gnu/guix/guixsd-install-0.16.0.i686-linux.iso.xz
> (I haven’t tried smaller padding.)
I downloaded it and get on "xorriso -indev":
libisoburn: WARNING : ISO image size 481129s larger than readable size 479184s
So the lack of 2k blocks is 1945 = nearly 4 MiB.
This is suspiciously near to the default fifo size.
The content of cleartext files near the payload end looks plausible:
/System/Library/CoreServices/.disk_label
/System/Library/CoreServices/SystemVersion.plist
Whether the last file's content is as expected can only be told by
its reader program, i guess:
/var/guix/db/db.sqlite
So for now it indeed looks like plain truncation and not like a hickup
somewhere in the middle of ISO writing.
Several distros use xorriso to build their 32 bit ISOs. No complaints.
So i asked on debian-cd and debian-live mailing lists whether the ISOs
for 32-bit systems are indeed made on 32-bit systems. The answer is
"All our images have been made on amd64 for years now."
So i need a 32-bit GNU/Linux VM for regression tests.
Being an untalented sysadmin, this can last a while. (First searching
for old cheat sheets and then stepping into any possible puddle ...)
I would still appreciate a test with minmally sized fifo. Its outcome would
be a strong indication whether the Guix problem is related to the fifo
at all. The result can be checked by executing
xorriso -indev ...path.to.iso...
and looking for message
libisoburn: WARNING : ISO image size ...s larger than readable size ...s
If the difference is in the range of only 32s, then the fifo stays
main suspect.
Also, the xorriso messages of a run with grub-mkrescue add-on arguments
-- -- -report_about all
would be very welcome.
--------------------------------------------------------------------------
(Be invited to stop reading here. Only code musings follow.)
I reviewed the fifo code in libisofs and found no obvious opportunity for
a bug that would drop the final fifo content rather than offering it to
libburn:
https://dev.lovelyhq.com/libburnia/libisofs/raw/master/libisofs/buffer.c
(iso_ring_buffer_read() is exposed to libburn via libisofs/ecma119.c
function bs_read() which serves as struct burn_source member (*read)()
as defined in libburn/libburn.h.)
The condition for end of reading is a combination of
- no data are available in the ring buffer
- the writer has set the flag for having ended its work
while (buf->size == 0) {
...
if (buf->wend) {
The member buf->size is of type size_t. I.e. good for at least 4 GiB - 1
before it rolls over. Neither the fifo size nor the transaction size come
near to that number.
buf->wend is unsigned int :2 with defined values
0 not finished, 1 finished ok, 2 finish with error
Have a nice day :)
Thomas
next prev parent reply other threads:[~2018-12-08 12:44 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 0:02 bug#33639: ISO installer image is broken on i686 Ludovic Courtès
2018-12-06 7:19 ` Ludovic Courtès
2018-12-06 10:34 ` Ludovic Courtès
2018-12-06 14:08 ` Thomas Schmitt
2018-12-06 15:34 ` Ludovic Courtès
2018-12-06 16:59 ` Thomas Schmitt
2018-12-15 18:40 ` Thomas Schmitt
2018-12-15 19:24 ` Thomas Schmitt
2018-12-16 15:52 ` Ludovic Courtès
2018-12-16 16:52 ` Thomas Schmitt
2018-12-18 11:16 ` Ludovic Courtès
2018-12-18 21:45 ` Thomas Schmitt
2018-12-19 14:05 ` Ludovic Courtès
2018-12-19 14:51 ` Thomas Schmitt
2018-12-20 13:38 ` Thomas Schmitt
2018-12-21 20:44 ` Ludovic Courtès
2018-12-21 21:42 ` Thomas Schmitt
2019-04-07 20:18 ` pelzflorian (Florian Pelz)
2019-04-07 21:35 ` Thomas Schmitt
2019-04-08 8:50 ` Ludovic Courtès
2019-04-09 22:13 ` pelzflorian (Florian Pelz)
2019-04-10 11:17 ` Thomas Schmitt
2019-04-10 21:23 ` pelzflorian (Florian Pelz)
2019-04-12 21:26 ` Ludovic Courtès
2019-04-13 6:37 ` Thomas Schmitt
2019-04-13 13:46 ` pelzflorian (Florian Pelz)
2019-04-13 16:20 ` Thomas Schmitt
2019-04-14 21:43 ` Ludovic Courtès
2019-04-15 6:07 ` pelzflorian (Florian Pelz)
2019-04-15 8:16 ` Thomas Schmitt
2019-04-15 8:35 ` Thomas Schmitt
2019-04-19 11:40 ` bug#35283: ISO images are not reproducible Ludovic Courtès
2019-04-19 12:46 ` Thomas Schmitt
2019-04-20 22:57 ` Ludovic Courtès
2019-04-21 8:17 ` Thomas Schmitt
2019-04-21 16:42 ` Ludovic Courtès
2019-04-21 18:44 ` Thomas Schmitt
2019-04-20 23:03 ` bug#35283: [PATCH] mformat: initialize boot sector before writing it Ludovic Courtès
2019-04-21 16:32 ` bug#35283: [PATCH] grub-mkrescue: Allow users to specify a FAT serial number Ludovic Courtès
2019-04-14 15:47 ` bug#33639: ISO installer image is broken on i686 Ludovic Courtès
2019-04-15 16:54 ` pelzflorian (Florian Pelz)
2019-04-15 17:55 ` Thomas Schmitt
2019-04-16 9:57 ` Gábor Boskovits
2019-04-16 21:01 ` Ludovic Courtès
2019-04-17 9:03 ` pelzflorian (Florian Pelz)
2018-12-06 16:28 ` Ludovic Courtès
2018-12-06 17:29 ` Thomas Schmitt
2018-12-07 22:51 ` Ludovic Courtès
2018-12-08 12:42 ` Thomas Schmitt [this message]
2018-12-06 9:35 ` swedebugia
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