linux/kernel/module.c, branch v2.6.34

Fix up possibly racy module refcounting

2010-04-06T02:50:02Z

Module refcounting is implemented with a per-cpu counter for speed. However there is a race when tallying the counter where a reference may be taken by one CPU and released by another. Reference count summation may then see the decrement without having seen the previous increment, leading to lower than expected count. A module which never has its actual reference drop below 1 may return a reference count of 0 due to this race. Module removal generally runs under stop_machine, which prevents this race causing bugs due to removal of in-use modules. However there are other real bugs in module.c code and driver code (module_refcount is exported) where the callers do not run under stop_machine. Fix this by maintaining running per-cpu counters for the number of module refcount increments and the number of refcount decrements. The increments are tallied after the decrements, so any decrement seen will always have its corresponding increment counted. The final refcount is the difference of the total increments and decrements, preventing a low-refcount from being returned. Signed-off-by: Nick Piggin Acked-by: Rusty Russell Signed-off-by: Linus Torvalds

percpu, module: implement and use is_kernel/module_percpu_address()

2010-03-29T14:07:12Z

lockdep has custom code to check whether a pointer belongs to static percpu area which is somewhat broken. Implement proper is_kernel/module_percpu_address() and replace the custom code. On UP, percpu variables are regular static variables and can't be distinguished from them. Always return %false on UP. Signed-off-by: Tejun Heo Acked-by: Peter Zijlstra Cc: Rusty Russell Cc: Ingo Molnar

module: encapsulate percpu handling better and record percpu_size

2010-03-29T14:07:12Z

Better encapsulate module static percpu area handling so that code outsidef of CONFIG_SMP ifdef doesn't deal with mod->percpu directly and add mod->percpu_size and record percpu_size in it. Both percpu fields are compiled out on UP. While at it, mark mod->percpu w/ __percpu. This is to prepare for is_module_percpu_address(). Signed-off-by: Tejun Heo Acked-by: Rusty Russell

sysfs: Use sysfs_attr_init and sysfs_bin_attr_init on module dynamic attributes

2010-03-08T01:04:51Z

A little more whack-a-mole annotating the dynamic sysfs attributes. I had everything built into my earlier test kernel, and so I missed these. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman

Merge branch 'master' into percpu

2010-02-02T05:38:15Z

modules: Skip empty sections when exporting section notes

2010-01-06T09:11:29Z

Commit 35dead4 "modules: don't export section names of empty sections via sysfs" changed the set of sections that have attributes, but did not change the iteration over these attributes in add_notes_attrs(). This can lead to add_notes_attrs() creating attributes with the wrong names or with null name pointers. Introduce a sect_empty() function and use it in both add_sect_attrs() and add_notes_attrs(). Reported-by: Martin Michlmayr Signed-off-by: Ben Hutchings Tested-by: Martin Michlmayr Cc: stable@kernel.org Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds

module: Use this_cpu_xx to dynamically allocate counters

2010-01-05T06:34:50Z

Use cpu ops to deal with the per cpu data instead of a local_t. Reduces memory requirements, cache footprint and decreases cycle counts. The this_cpu_xx operations are also used for !SMP mode. Otherwise we could not drop the use of __module_ref_addr() which would make per cpu data handling complicated. this_cpu_xx operations have their own fallback for !SMP. V8-V9: - Leave include asm/module.h since ringbuffer.c depends on it. Nothing else does though. Another patch will deal with that. - Remove spurious free. Signed-off-by: Christoph Lameter Acked-by: Rusty Russell Signed-off-by: Tejun Heo

Merge branch 'kmemleak' of git://linux-arm.org/linux-2.6

2009-12-18T00:00:19Z

* 'kmemleak' of git://linux-arm.org/linux-2.6: kmemleak: fix kconfig for crc32 build error kmemleak: Reduce the false positives by checking for modified objects kmemleak: Show the age of an unreferenced object kmemleak: Release the object lock before calling put_object() kmemleak: Scan the _ftrace_events section in modules kmemleak: Simplify the kmemleak_scan_area() function prototype kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE

module: handle ppc64 relocating kcrctabs when CONFIG_RELOCATABLE=y

2009-12-15T05:58:34Z

powerpc applies relocations to the kcrctab. They're absolute symbols, but it's not completely unreasonable: other archs may too, but the relocation is often 0. http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-November/077972.html Inspired-by: Neil Horman Signed-off-by: Rusty Russell Tested-by: Neil Horman Acked-by: Paul Mackerras

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2009-12-14T17:58:24Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits) m68k: rename global variable vmalloc_end to m68k_vmalloc_end percpu: add missing per_cpu_ptr_to_phys() definition for UP percpu: Fix kdump failure if booted with percpu_alloc=page percpu: make misc percpu symbols unique percpu: make percpu symbols in ia64 unique percpu: make percpu symbols in powerpc unique percpu: make percpu symbols in x86 unique percpu: make percpu symbols in xen unique percpu: make percpu symbols in cpufreq unique percpu: make percpu symbols in oprofile unique percpu: make percpu symbols in tracer unique percpu: make percpu symbols under kernel/ and mm/ unique percpu: remove some sparse warnings percpu: make alloc_percpu() handle array types vmalloc: fix use of non-existent percpu variable in put_cpu_var() this_cpu: Use this_cpu_xx in trace_functions_graph.c this_cpu: Use this_cpu_xx for ftrace this_cpu: Use this_cpu_xx in nmi handling this_cpu: Use this_cpu operations in RCU this_cpu: Use this_cpu ops for VM statistics ... Fix up trivial (famous last words) global per-cpu naming conflicts in arch/x86/kvm/svm.c mm/slab.c