ubuntu-x-swat team mailing list archive

[Andrew Pollock <apollock@xxxxxxxxxx>]

Public bug reported:

Hi,

We have some internal 32-bit applications that end up with a lot of
files open. If they in turn call a program that links with libxcb, more
often than not, that program segfaults.

This has been determined to be because libxcb uses select() and the man
page for select() says this:

"An  fd_set  is  a  fixed size buffer.  Executing FD_CLR() or FD_SET()
with a value of fd that is negative or is equal to or larger than
FD_SETSIZE will result in undefined behavior.  Moreover, POSIX requires
fd to be a valid file descriptor."

Later versions of libxcb address this by using poll()

I'm attaching the patch that we are using internally against libxcb
1.1-1.1

If you make this SRU, please also ensure that the 32-bit version in
ia32-libs gets updated.

** Affects: libxcb (Ubuntu)
     Importance: Undecided
         Status: New

-- 
Applications that use libxcb 1.1 cannot open more than 1024 files
https://bugs.launchpad.net/bugs/393509
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