Bug 89734

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Description of problem:
With the test-4.1.1 or test-4.2 RPMs under RH 8.0 or 9, running rpm -qa at the
same time as an RPM install or erase can lead to errors like the following:

error: rpmdbNextIterator: skipping h#    5729 blob size(8288): BAD, 8 + 16 *
il(-393797231) + dl(-2133992638)

I did not try testing RPM 4.1 or 4.2 as shipped with RH 8.0 or 9. This bug does
not seem to happen with RPM 4.0.4 or test-4.0.5, nor does it happen with NPTL on
RH 9. (For more detail on RH 9, see the Steps to Reproduce.)

Version-Release number of selected component (if applicable):
rpm-4.2-1

How reproducible:
Depends on the setting of the magic constant in step 2 (see "Steps to
Reproduce"), and perhaps the performance characteristics of the computer you're
running it on. I suppose it's not 100% reproducible but it's not far off.

Steps to Reproduce:
For RH 8.0:

1. As root, run the following shell command/script:
while : ; do rpm -e --justdb kernel-utils ; rpm -i --just
db kernel-utils-2.4-8.28.i386.rpm ;sleep 1;done

(Change the version number etc. of the kernel-utils RPM file as needed to match
whatever you actually use in testing.)

2. Leave the command from step 1 running. In a separate console, run the
following command/script as a normal user:
for z in `seq 1 16` ; do rpm -qa > /dev/null & done
(Increasing "16" to something bigger will slow things down but increase
reproducibility. The opposite applies to reducing that number.)

3. In a third console, run top so you can see when all the rpmq processes stop
running.

4. Look at the second console, and wait a minute or two. If all the rpmq
processes disappear from top for more than one or two top snapshots, step 2
probably finished; if the bug did not reproduce, repeat step 2 with a larger
constant.

For Red Hat 9: Run the command "LD_ASSUME_KERNEL=2.2.5" in the first and/or
second console, before steps 1 or 2 repectively. (If that command is run in
neither console, I am unable to reproduce the bug.)

Actual Results:  Output from one session on Red Hat 8 (test-4.1.1):
[barryn@localhost barryn]$ for z in `seq 1 7` ; do rpm -qa > /dev/null & done
[1] 1604
[2] 1605
[3] 1606
[4] 1607
[5] 1608
[6] 1609
[7] 1610
[barryn@localhost barryn]$ error: rpmdbNextIterator: skipping h#    5729 blob
size(8288): BAD, 8 + 16 * il(-393797231) + dl(-2133992638)

(Note that most of my test runs were actually more noisy than this.)

Expected Results:  AFAIK those rpmdbNextIterator errors shouldn't be happening.

Additional info:

I don't know if there are any more serious consequences to this, but I thought
it might be worth reporting.