tl;dr: I think there is a bug in libvirt's build system which, with low probability, causes a build failure containing this message: /usr/bin/ld: cannot find -lvirt Complete build logs of two attempts: http://logs.test-lab.xenproject.org/osstest/logs/123046/build-i386-libvir... http://logs.test-lab.xenproject.org/osstest/logs/123096/build-i386-libvir... Snippet from 123046 containing the error is enclosed below. Longer explanation: I have two new machines for the Xen Project CI, which I am trying to commission. As part of commissioning I run a complete test run (a "flight" in osstest terminology) on just those new hosts. The i386 libvirt build failed: http://logs.test-lab.xenproject.org/osstest/logs/123046/build-i386-libvir... Everything else that would be expected to work was fine. The test programme was identical to flight 122815, except that that ran on other hosts in the test farm (and, there, it passed). The error is the kind of error one sees with missing dependencies in parallel builds, etc. I wanted to have some 32-bit libvirt tests actually run, so I reran a new flight containing the relevant parts. That failed too in a very similar way: http://logs.test-lab.xenproject.org/osstest/logs/123096/build-i386-libvir... The two machines are Dell R230s (and therefore hardly unusual). The main novelty of these machines is that the firmware is UEFI booting in UEFI mode. I doubt that has anything to do with it. The host, including compiler, is Debian jessie i386. As you can see from the log, we were trying to build libvirt 764a7483f189e6de841163647c14296e693dbb2e What may be less obvious is that we were trying to build it against xen.git#0306a1311d02ea52b4a9a9bc339f8bab9354c5e3. http://logs.test-lab.xenproject.org/osstest/logs/123064/build-i386-libvir... http://logs.test-lab.xenproject.org/osstest/logs/123046/build-i386/info.html Does this seem like a likely explanation ? Have other people experienced occasional problems with make -j ? If someone wants to suggest a patch that might fix it I can test it. In the meantime I have set off a number of new attempts, to try to guess the failure probability, and also one attempt on other hosts to check that nothing unexpected was broken. Ian. /usr/bin/ld: cannot find -lvirt /usr/bin/ld: cannot find -lvirt /bin/mkdir -p '/home/osstest/build.123046.build-i386-libvirt/dist/usr/local/lib/libvirt/storage-backend' /bin/bash ../libtool --mode=install /usr/bin/install -c libvirt_storage_backend_fs.la libvirt_storage_backend_logical.la libvirt_storage_backend_scsi.la libvirt_storage_backend_mpath.la '/home/osstest/build.123046.build-i386-libvirt/dist/usr/local/lib/libvirt/storage-backend' libtool: install: warning: relinking `libvirt_storage_backend_fs.la' libtool: install: (cd /home/osstest/build.123046.build-i386-libvirt/libvirt/src; /bin/bash /home/osstest/build.123046.build-i386-libvirt/libvirt/libtool --silent --tag CC --mode=relink gcc -std=gnu99 -I./conf -I/usr/include/libxml2 -fno-common -W -Waddress -Waggressive-loop-optimizations -Wall -Wattributes -Wbad-function-cast -Wbuiltin-macro-redefined -Wcast-align -Wchar-subscripts -Wclobbered -Wcomment -Wcomments -Wcoverage-mismatch -Wcpp -Wdate-time -Wdeprecated-declarations -Wdiv-by-zero -Wdouble-promotion -Wempty-body -Wendif-labels -Wextra -Wformat-contains-nul -Wformat-extra-args -Wformat-security -Wformat-y2k -Wformat-zero-length -Wfree-nonheap-object -Wignored-qualifiers -Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Winit-self -Winline -Wint-to-pointer-cast -Winvalid-memory-model -Winvalid-pch -Wjump-misses-init -Wlogical-op -Wmain -Wmaybe-uninitialized -Wmemset-transposed-args -Wmissing-braces -Wmissing-declarations -Wmissing-field-initializers -Wmissing-include-dirs -Wmissing-parameter-type -Wmissing-prototypes -Wmultichar -Wnarrowing -Wnested-externs -Wnonnull -Wold-style-declaration -Wold-style-definition -Wopenmp-simd -Woverflow -Woverride-init -Wpacked-bitfield-compat -Wparentheses -Wpointer-arith -Wpointer-sign -Wpointer-to-int-cast -Wpragmas -Wpsabi -Wreturn-local-addr -Wreturn-type -Wsequence-point -Wshadow -Wsizeof-pointer-memaccess -Wstrict-aliasing -Wstrict-prototypes -Wsuggest-attribute=const -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wswitch -Wsync-nand -Wtrampolines -Wtrigraphs -Wtype-limits -Wuninitialized -Wunknown-pragmas -Wunused -Wunused-but-set-parameter -Wunused-but-set-variable -Wunused-function -Wunused-label -Wunused-local-typedefs -Wunused-parameter -Wunused-result -Wunused-value -Wunused-variable -Wvarargs -Wvariadic-macros -Wvector-operation-performance -Wvolatile-register-var -Wwrite-strings -Wnormalized=nfc -Wno-sign-compare -Wjump-misses-init -Wswitch-enum -Wno-format-nonliteral -fstack-protector-strong -fexceptions -fasyn chronous-unwind-tables -fipa-pure-const -Wno-suggest-attribute=pure -Wno-suggest-attribute=const -Werror -Wframe-larger-than=4096 -g -I/home/osstest/build.123046.build-i386-libvirt/xendist/usr/local/include/ -DLIBXL_API_VERSION=0x040400 -module -avoid-version -Wl,-z -Wl,nodelete -export-dynamic -Wl,-z -Wl,relro -Wl,-z -Wl,now -Wl,--no-copy-dt-needed-entries -g -L/home/osstest/build.123046.build-i386-libvirt/xendist/usr/local/lib/ -Wl,-rpath-link=/home/osstest/build.123046.build-i386-libvirt/xendist/usr/local/lib/ -o libvirt_storage_backend_fs.la -rpath /usr/local/lib/libvirt/storage-backend storage/libvirt_storage_backend_fs_la-storage_backend_fs.lo libvirt.la ../gnulib/lib/libgnu.la -ldl -inst-prefix-dir /home/osstest/build.123046.build-i386-libvirt/dist) collect2: error: ld returned 1 exit status Makefile:6410: recipe for target 'install-lockdriverLTLIBRARIES' failed libtool: install: error: relink `lockd.la' with the above command before installing it make[3]: *** [install-lockdriverLTLIBRARIES] Error 1 make[3]: *** Waiting for unfinished jobs.... /usr/bin/ld: cannot find -lvirt