Bug#537509: libc6: 2.9 unneecssarily breaks eventfd and signalfd with older kernels

[Marc Lehmann <debian-reportbug@plan9.de>]

Package: libc6
Version: 2.9-12
Severity: normal


glibc-2.9 unnecssarily breaks compatibility with older kernels and
eventfd/signalfd.

with glibc-2.7 and 2.8, eventfd and signalfd work with kernels <2.6.27, as
they call the old syscall number.

glibc-2.9 *only* calls the newer syscall number.

that means that programs that could get eventfd's/signalfds with an older
libcs cannot do so with newer ones, even though the kernel supports it.

it would be better if glibc fell back to the old syscall when the new one
returns ENOSYS, or calls the old one first if flags == 0.

-- System Information:
Debian Release: 5.0
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.26-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages libc6 depends on:
ii  libgcc1                   1:4.4.0-1~exp1 GCC support library

libc6 recommends no packages.

Versions of packages libc6 suggests:
hi  glibc-doc                     2.7-18     GNU C Library: Documentation
hi  locales                       2.9-12     GNU C Library: National Language (

-- debconf information excluded