Commit Graph

5 Commits

Author SHA1 Message Date
Chris Dunlop a1d9543a39 3.10 API change: block_device_operations->release() returns void
Linux kernel commit torvalds/linux@db2a144 changed the return type
of block_device_operations->release() to void.  Detect the expected
prototype and defined our callout accordingly.

Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes 
2013-07-08 15:41:57 -07:00
Richard Yao c38367c73f Eliminate runtime function pointer mods in autotools checks
PaX/GrSecurity patched kernels implement a dialect of C that relies on a
GCC plugin for enforcement. A basic idea in this dialect is that
function pointers in structures should not change during runtime.
This causes code that modifies function pointers at runtime to fail to
compile in many instances. The autotools checks rely on whether or
not small test cases compile against a given kernel. Some
autotools checks assume some default case if other cases fail. When one
of these autotools checks tests a PaX/GrSecurity patched kernel by
modifying a function pointer at runtime, the default case will be used.

Early detection of such situations is possible by relying on compiler
warnings, which are compiler errors when --enable-debug is used.
Unfortunately, very few people build ZFS with --enable-debug. The more
common situation is that these issues manifest themselves as runtime
failures in the form of NULL pointer exceptions.

Previous patches that addressed such issues with PaX/GrSecurity
compatibility largely relied on rewriting autotools checks to avoid
runtime function pointer modification or the addition of PaX/GrSecurity
specific checks. This patch takes the previous work to its logical
conclusion by eliminating the use of runtime function pointer
modification. This permits the removal of PaX-specific autotools checks
in favor of ones that work across all supported kernels.

This should resolve issues that were reported to occur with
PaX/GrSecurity-patched Linux 3.7.5 kernels on Gentoo Linux.

https://bugs.gentoo.org/show_bug.cgi?id=457176

We should be able to prevent future regressions in PaX/GrSecurity
compatibility by ensuring that all changes to ZFSOnLinux avoid runtime
function pointer modification. At the same time, this does not solve the
issue of silent failures triggering default cases in the autotools
check, which is what permitted these regressions to become runtime
failures in the first place. This will need to be addressed in a future
patch.

Reported-by: Marcin Mirosław <bug@mejor.pl>
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes 
2013-03-04 08:49:17 -08:00
Brian Behlendorf e191b54ecf Only use gcc -Wunused-but-set-variable when available
Certain versions of gcc generate an 'unrecognized command
line option' error message when -Wunused-but-set-variable
is used unconditionally.  This in turn can cause several
of the autoconf tests to misdetect an interface.

Now, the use of -Wunused-but-set-variable in the autoconf
tests was introduced by commit b9c59ec8 to address a gcc
4.6 compatibility problem.  So we really only need to pass
this option for version of gcc which are known to support it.

Therefore, the tests have been updated to use the result of
the existing ZFS_AC_CONFIG_ALWAYS_NO_UNUSED_BUT_SET_VARIABLE
which determines if gcc supports this option.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes 
2013-01-10 16:09:39 -08:00
Prakash Surya b9c59ec83a Fix configure tests to play nice with GCC 4.6
As of GCC 4.6, specific kernel 2.6.32 header files do not compile
cleanly without warnings. One specific example of this is the
arch/x86/include/asm/percpu.h file. Thus, a few of the configure tests
were getting hung up on this and the '-Wno-unsued-but-set-variables'
compile option had to be introduced.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes 
2011-11-29 16:14:25 -08:00
Brian Behlendorf c9c0d073da Add build system
Add autoconf style build infrastructure to the ZFS tree.  This
includes autogen.sh, configure.ac, m4 macros, some scripts/*,
and makefiles for all the core ZFS components.
2010-08-31 13:41:27 -07:00