Bug #28456 my_global.h inappropriately depends on kernel header asm/atomic.h
Submitted: 15 May 2007 22:45 Modified: 1 Nov 2012 10:31
Reporter: Monty Taylor Email Updates:
Status: Won't fix Impact on me:
Category:MySQL Server: Compiling Severity:S3 (Non-critical)
Version:5.0.38 OS:Linux
Assigned to: CPU Architecture:Any

[15 May 2007 22:45] Monty Taylor
Got the following reported downstream in debian (debian bug#424276)

Packages build-depending on libmysqlclient15-dev will fail to build in
unstable on (at least) amd64 systems using the new linux-libc-dev package in
place of the obsoleted linux-kernel-headers, because my_global.h has a
dependency on asm/atomic.h:

 gcc -DHAVE_CONFIG_H -I. -I. -I. -D_REENTRANT -D_GNU_SOURCE -I/usr/include -O3 -DDBUG_OFF -I/usr/include/mysql -DBIG_JOINS=1 -g -Wall -O2 -MT libmyodbc3_la-catalog.lo -MD -MP -MF .deps/libmyodbc3_la-catalog.Tpo -c catalog.c  -fPIC -DPIC -o .libs/libmyodbc3_la-catalog.o
In file included from ../MYODBC_MYSQL.h:11,
                 from myodbc3.h:37,
                 from catalog.c:44:
/usr/include/mysql/my_global.h:353:24: error: asm/atomic.h: No such file or directory
make[3]: *** [libmyodbc3_la-catalog.lo] Error 1

According to kernel upstream[1], asm/atomic.h is not an appropriate header
for inclusion from userspace; and indeed, on some architectures such as
i386, libmysqlclient works fine without HAVE_ATOMIC_ADD being defined.

I suspect that a simple rebuild (i.e., binNMU) of mysql-dfsg-5.0 against
linux-libc-dev would be enough to fix the symptoms of this bug, but I'm
filing a sourceful bug report instead for two reasons:

- not all buildds have linux-libc-dev installed yet, and this won't be
  enforced for some time, making it difficult to get this issue covered for
  all archs in a timely manner through binNMUs
- even if asm/atomic.h is present on the system, it is still an error for
  libmysqlclient15-dev to depend on it, and this is a bug in the source
  package which should be fixed by hard-disabling the check.

Please fix this bug ASAP so that developing against libmysqlclient on
amd64/unstable works again.

How to repeat:
I'm guessing that trying to build something on a recent Debian sid system that has replaced the linux-kernel-headers package with the linux-libc-dev package would be a good start.

Suggested fix:
Don't use asm/atomic.h if it's not intended to be public. Or put something in configure that prevents its use on platforms that don't have it better.
[17 May 2007 8:42] Sveta Smirnova
Thank you for the report.

Verified as described using code analysis.

See also http://docs.fedoraproject.org/release-notes/fc6/en_US/sn-Devel.html:

12.2.1. Kernel header files
    * The <asm/atomic.h> and <asm/bitops.h> header files have been removed. These were not designed for use in userspace, and would fail to compile on some architectures while silently giving non-atomic behaviour on others. The C compiler provides its own atomic builtin functions that are suitable for use in userspace programs instead.
[22 May 2007 1:45] Marc ALFF
Related to Bug#21554
[23 Oct 2007 15:39] Baron Schwartz
I downloaded mysql-5.0.45-linux-x86_64-glibc23.tar.gz and encountered the error mentioned by the reporter, while trying to build a UDF with the following command:

gcc -fPIC -Wall -I/home/baron/5.0.45/include/ -shared -o now_usec.so now_usec.cc

Since the bug report seems to indicate atomic add might not be all that important, I tried just removing the #include <asm/atomic.h> line, and the UDF built okay.  But now,

master [localhost] {msandbox} (mysql) > create function now_usec returns string soname 'now_usec.so';
ERROR 1126 (HY000): Can't open shared library 'now_usec.so' (errno: 22 /lib/now_usec.so: undefined symbol: __gxx_personality_v0)

I'm adding this comment in hopes it's related.  Ubuntu 7.04 on AMD64:

baron@tigger rsandbox $ uname -a
Linux tigger 2.6.20-16-generic #2 SMP Sun Sep 23 18:31:23 UTC 2007 x86_64 GNU/Linux
[25 Oct 2007 7:47] Robin Johnson
I confirm that this compile bug still exists in 5.0.46. The patch from #21554 applies with a little bit of manual fixup.

Downstream Gentoo bug is https://bugs.gentoo.org/show_bug.cgi?id=197004
[27 Aug 2009 18:02] Mark Callaghan
See this too -- http://lists.mysql.com/packagers/264

Note that the RHEL/CentOS source RPMs patch configure so that HAVE_ATOMIC_ADD is always not defined and then the thread_safe_* functions use a mutex, so RHEL/CentOS users lose a bit of performance.

#define thread_safe_increment(V,L) atomic_inc((atomic_t*) &V)
#define thread_safe_decrement(V,L) atomic_dec((atomic_t*) &V)
#define thread_safe_add(V,C,L)     atomic_add((C),(atomic_t*) &V)
#define thread_safe_sub(V,C,L)     atomic_sub((C),(atomic_t*) &V)
#define thread_safe_increment(V,L) \
        (pthread_mutex_lock((L)), (V)++, pthread_mutex_unlock((L)))
#define thread_safe_decrement(V,L) \
        (pthread_mutex_lock((L)), (V)--, pthread_mutex_unlock((L)))
#define thread_safe_add(V,C,L) (pthread_mutex_lock((L)), (V)+=(C), pthread_mutex_unlock((L)))
#define thread_safe_sub(V,C,L) \
        (pthread_mutex_lock((L)), (V)-=(C), pthread_mutex_unlock((L)))
#endif /* HAVE_ATOMIC_ADD */
[1 Nov 2012 10:31] Ståle Deraas
Only relevant for 5.0, and as such not feasible to fix.