Messages in this thread | | | From | Andreas Dilger <> | Subject | Re: 2.4 and 2GB swap partition limit | Date | Wed, 2 May 2001 16:17:21 -0600 (MDT) |
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Andi Kleen writes: > On Mon, Apr 30, 2001 at 12:07:44PM -0700, David S. Miller wrote: > But something must have been not working with it for mmaps/shlibs > (not executables); at least historically. > At least I remember that all hell broke lose when you tried to update > libc by cp'ing a new one to /lib/libc.so in the 1.2 days. cp should create a > new inode (it uses O_CREAT) so in theory it should be coherent by the inode > reference; but somehow it didn't use to work and random already running > programs started to segfault. This was long ago. I wonder if old > GNU cp used O_TRUNC instead of O_CREAT, or was there some other kernel bug > with mappings (hopefully long since fixed). Anybody remembers?
No, "cp" is still not a safe way to update libc, and I doubt it ever will be. cp does _not_ create a new inode (unlike mv), so you are writing "garbage" into the currently running executables.
NB: my open(2) says for O_CREAT "If the file does not exist it will be created". This is _not_ the same as O_EXCL, which will only mean that open(2) will fail when it tries to create a new file.
Cheers, Andreas -- Andreas Dilger Turbolinux filesystem development http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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