Red Hat Bugzilla – Bug 90648
rpmlib can lock against itself
Last modified: 2007-04-18 12:53:39 EDT
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Description of problem:
If you create an rpm iterator with rpmtsInitIterator() and don't free it before
running rpmtsRun() or possibly other things, rpmlib will hang in futex() trying
to lock against itself.
This is arguably a programmer error (though I'm not aware of any documentation
saying that you can't do this), but some assertions seem warranted if so.
I will attached a test program illustrating the hang.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Build the attached test program with:
cc -I/usr/include/rpm rpmtest.c -o rpmtest -lrpm
2. Run it on a system with the ash rpm installed.
Created attachment 91611 [details]
Test program illustrating rpmlib hang
Yup, a (shared) read lock will prevent an (exclusive) write lock
on the same object.
"Don't do that" is a bit nicer than "Programmer error.", as concurrent
access works just fine in Berkeley DB used by rpm-4.2-1.