On Sat, Jan 30, 2016 at 08:42:59PM +0100, Stefan Bühler wrote: > Hi, > > On Sat, 30 Jan 2016 15:03:27 +0100 > Julian Andres Klode <j...@debian.org> wrote: > > > On 30 January 2016 at 13:42, Stefan Bühler <stbueh...@web.de> wrote: > > > [...] > > > ==890== Conditional jump or move depends on uninitialised value(s) > > > ==890== at 0x4F4D8A0: pkgCache::ReMap(bool const&) > > > (in /usr/lib/x86_64-linux-gnu/libapt-pkg.so.5.0.0)> > > > > [...] > > > I managed to track down the code (pkgCache::ReMap+0x2d0) in gdbs > > > disassembly to pkgcache.cc:199: > > > if (hash != HeaderP->CacheFileSize) > > > > That's not an issue, it's expected. We mmap() the memory, and then > > hash the entire memory we mapped, as that's what we are writing to the > > disk. It does not matter that there are uninitialized values in there, > > we just want to check that if we have written it to a file and read it > > back, that it's the same. > > That is sad; I can see now that it should work, but it would be nice if > this could be fixed one day.
It is. > > > > Disabling lz4 seems to fix the issue (but not the valgrind report): > > > > > > echo 'APT::Compressor::lz4::Cost "5000";' > > > > /etc/apt/apt.conf.d/disable-lz4 rm /var/lib/apt/lists/*.lz4 > > > apt-get update > > > > OK. Not sure how that happens. > > I might add that the docker/debootstrap combo sets (among others) the > following options by default: > > Acquire::GzipIndexes "true"; > Acquire::CompressionTypes::Order:: "gz"; > > I think in fileutl.cc Lz4FileFdPrivate::InternalOpen() needs to reset > next_to_load = APT_BUFFER_SIZE, as otherwise a Seek() after reaching > end of file won't read anything anymore due to next_to_load == 0. It should be calling close before reopening it again, or as part of the reopening, I don't remember. -- Julian Andres Klode - Debian Developer, Ubuntu Member See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/. When replying, only quote what is necessary, and write each reply directly below the part(s) it pertains to (`inline'). Thank you.
