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 <npiggin@suse.de>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <tj@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
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 <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
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 <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <tbm@cyrius.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Martin Michlmayr <tbm@cyrius.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <cl@linux-foundation.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
* '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
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 <nhorman@tuxdriver.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Paul Mackerras <paulus@samba.org>
* '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
On the parisc architecture we face for each and every loaded kernel module
this kernel "badness warning":
sysfs: cannot create duplicate filename '/module/ac97_bus/sections/.text'
Badness at fs/sysfs/dir.c:487
Reason for that is, that on parisc all kernel modules do have multiple
.text sections due to the usage of the -ffunction-sections compiler flag
which is needed to reach all jump targets on this platform.
An objdump on such a kernel module gives:
Sections:
Idx Name Size VMA LMA File off Algn
0 .note.gnu.build-id 00000024 00000000 00000000 00000034 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .text 00000000 00000000 00000000 00000058 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
2 .text.ac97_bus_match 0000001c 00000000 00000000 00000058 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
3 .text 00000000 00000000 00000000 000000d4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
...
Since the .text sections are empty (size of 0 bytes) and won't be
loaded by the kernel module loader anyway, I don't see a reason
why such sections need to be listed under
/sys/module/<module_name>/sections/<section_name> either.
The attached patch does solve this issue by not exporting section
names which are empty.
This fixes bugzilla http://bugzilla.kernel.org/show_bug.cgi?id=14703
Signed-off-by: Helge Deller <deller@gmx.de>
CC: rusty@rustcorp.com.au
CC: akpm@linux-foundation.org
CC: James.Bottomley@HansenPartnership.com
CC: roland@redhat.com
CC: dave@hiauly1.hia.nrc.ca
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This section contains pointers to allocated objects and not scanning it
leads to false positives.
Reported-by: Zdenek Kabelac <zdenek.kabelac@gmail.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This function was taking non-necessary arguments which can be determined
by kmemleak. The patch also modifies the calling sites.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
With ia64 converted, there's no arch left which still uses legacy
percpu allocator. Kill it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Delightedly-acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Starting from commit 4a4962263f "reduce
symbol table for loaded modules (v2)", the kernel/module.c build is broken
with CONFIG_KALLSYMS disabled.
CC kernel/module.o
kernel/module.c:1995: warning: type defaults to 'int' in declaration of 'Elf_Hdr'
kernel/module.c:1995: error: expected ';', ',' or ')' before '*' token
kernel/module.c: In function 'load_module':
kernel/module.c:2203: error: 'strmap' undeclared (first use in this function)
kernel/module.c:2203: error: (Each undeclared identifier is reported only once
kernel/module.c:2203: error: for each function it appears in.)
kernel/module.c:2239: error: 'symoffs' undeclared (first use in this function)
kernel/module.c:2239: error: implicit declaration of function 'layout_symtab'
kernel/module.c:2240: error: 'stroffs' undeclared (first use in this function)
make[1]: *** [kernel/module.o] Error 1
make: *** [kernel/module.o] Error 2
There are three different issues:
- layout_symtab() takes a const Elf_Ehdr
- layout_symtab() needs to return a value
- symoffs/stroffs/strmap are referenced by the load_module() code
despite being ifdefed out, which seems unnecessary given the noop
behaviour of layout_symtab()/add_kallsyms() in the case of
CONFIG_KALLSYMS=n.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
modules, tracing: Remove stale struct marker signature from module_layout()
tracing/workqueue: Use %pf in workqueue trace events
tracing: Fix a comment and a trivial format issue in tracepoint.h
tracing: Fix failure path in ftrace_regex_open()
tracing: Fix failure path in ftrace_graph_write()
tracing: Check the return value of trace_get_user()
tracing: Fix off-by-one in trace_get_user()
The general one handles NULL, the static obsolescent
(CONFIG_HAVE_LEGACY_PER_CPU_AREA) one in module.c doesn't; Eric's
commit 720eba31 assumed it did, and various frobbings since then kept
that assumption.
All other callers in module.c all protect it with an if; this effectively
does the same as free_init is only goto if we fail percpu_modalloc().
Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Normally the twisty paths of sysfs will free the attributes, but not if
we fail before we hook it into sysfs (which is the last thing we do in
load_module).
(This sysfs code is a turd, no doubt there are other issues lurking too).
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Also remove all parts of the string table (referenced by the symbol
table) that are not needed for kallsyms use (i.e. which were only
referenced by symbols discarded by the previous patch, or not
referenced at all for whatever reason).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Discard all symbols not interesting for kallsyms use: absolute,
section, and in the common case (!KALLSYMS_ALL) data ones.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Linus reported this new build warning:
kernel/module.c:2951: warning: ?struct marker? declared inside parameter list
kernel/module.c:2951: warning: its scope is only this definition or declaration, which is probably not what you want
Caused by:
fc53776: tracing: Remove markers
module_layout() is an artificial symbol with 'significant' symbols
listed in its argument list so that it gets a proper argument types
signature that modversions can pick up to decide whether a
module is version-compatible or not. If these dont match then we
wont even look at a module.
Remove the stale marker symbol.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.01.0909210908020.4950@localhost.localdomain>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some architectures (like the Blackfin arch) implement some of the
"simpler" features that one would expect out of a MMU such as memory
protection.
In our case, we actually get read/write/exec protection down to the page
boundary so processes can't stomp on each other let alone the kernel.
There is a performance decrease (which depends greatly on the workload)
however as the hardware/software interaction was not optimized at design
time.
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the last users of markers have migrated to the event
tracer we can kill off the (now orphan) support code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090917173527.GA1699@lst.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits)
powerpc64: convert to dynamic percpu allocator
sparc64: use embedding percpu first chunk allocator
percpu: kill lpage first chunk allocator
x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA
percpu: update embedding first chunk allocator to handle sparse units
percpu: use group information to allocate vmap areas sparsely
vmalloc: implement pcpu_get_vm_areas()
vmalloc: separate out insert_vmalloc_vm()
percpu: add chunk->base_addr
percpu: add pcpu_unit_offsets[]
percpu: introduce pcpu_alloc_info and pcpu_group_info
percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward
percpu: add @align to pcpu_fc_alloc_fn_t
percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()
percpu: drop @static_size from first chunk allocators
percpu: generalize first chunk allocator selection
percpu: build first chunk allocators selectively
percpu: rename 4k first chunk allocator to page
percpu: improve boot messages
percpu: fix pcpu_reclaim() locking
...
Fix trivial conflict as by Tejun Heo in kernel/sched.c
> James Bottomley (1):
> module: workaround duplicate section names
-tip testing found that this patch breaks the build on x86 if
CONFIG_KALLSYMS is disabled:
kernel/module.c: In function ‘load_module’:
kernel/module.c:2367: error: ‘struct module’ has no member named ‘sect_attrs’
distcc[8269] ERROR: compile kernel/module.c on ph/32 failed
make[1]: *** [kernel/module.o] Error 1
make: *** [kernel] Error 2
make: *** Waiting for unfinished jobs....
Commit 1b364bf misses the fact that section attributes are only
built and dealt with if kallsyms is enabled. The patch below fixes
this.
( note, technically speaking this should depend on CONFIG_SYSFS as
well but this patch is correct too and keeps the #ifdef less
intrusive - in the KALLSYMS && !SYSFS case the code is a NOP. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[ Replaced patch with a slightly cleaner variation by James Bottomley ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The root cause is a duplicate section name (.text); is this legal?
[ Amerigo Wang: "AFAIK, yes." ]
However, there's a problem with commit
6d76013381 in that if you fail to allocate
a mod->sect_attrs (in this case it's null because of the duplication),
it still gets used without checking in add_notes_attrs()
This should fix it
[ This patch leaves other problems, particularly the sections directory,
but recent parisc toolchains seem to produce these modules and this
prevents a crash and is a minimal change -- RR ]
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rarely-used symbol_put_addr() needs to use dereference_function_descriptor
on powerpc.
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Conflicts:
arch/sparc/kernel/smp_64.c
arch/x86/kernel/cpu/perf_counter.c
arch/x86/kernel/setup_percpu.c
drivers/cpufreq/cpufreq_ondemand.c
mm/percpu.c
Conflicts in core and arch percpu codes are mostly from commit
ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many
num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all
the first chunk allocators into mm/percpu.c, the changes are moved
from arch code to mm/percpu.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
The check_modstruct_version() needs to look up the symbol "module_layout"
in the kernel, but it does so literally and not by a C identifier. The
trouble is that it does not include a symbol prefix for those ports that
need it (like the Blackfin and H8300 port). So make sure we tack on the
MODULE_SYMBOL_PREFIX define to the front of it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 5fd29d6ccb ("printk: clean up
handling of log-levels and newlines") changed printk semantics. printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.
<level> is now included in the output on each additional use.
Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch makes most !CONFIG_HAVE_SETUP_PER_CPU_AREA archs use
dynamic percpu allocator. The first chunk is allocated using
embedding helper and 8k is reserved for modules. This ensures that
the new allocator behaves almost identically to the original allocator
as long as static percpu variables are concerned, so it shouldn't
introduce much breakage.
s390 and alpha use custom SHIFT_PERCPU_PTR() to work around addressing
range limit the addressing model imposes. Unfortunately, this breaks
if the address is specified using a variable, so for now, the two
archs aren't converted.
The following architectures are affected by this change.
* sh
* arm
* cris
* mips
* sparc(32)
* blackfin
* avr32
* parisc (broken, under investigation)
* m32r
* powerpc(32)
As this change makes the dynamic allocator the default one,
CONFIG_HAVE_DYNAMIC_PER_CPU_AREA is replaced with its invert -
CONFIG_HAVE_LEGACY_PER_CPU_AREA, which is added to yet-to-be converted
archs. These archs implement their own setup_per_cpu_areas() and the
conversion is not trivial.
* powerpc(64)
* sparc(64)
* ia64
* alpha
* s390
Boot and batch alloc/free tests on x86_32 with debug code (x86_32
doesn't use default first chunk initialization). Compile tested on
sparc(32), powerpc(32), arm and alpha.
Kyle McMartin reported that this change breaks parisc. The problem is
still under investigation and he is okay with pushing this patch
forward and fixing parisc later.
[ Impact: use dynamic allocator for most archs w/o custom percpu setup ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Call constructors (gcc-generated initcall-like functions) during kernel
start and module load. Constructors are e.g. used for gcov data
initialization.
Disable constructor support for usermode Linux to prevent conflicts with
host glibc.
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several WARN_ON() messages omit the '\n' at the end of the string, which
is a simple (and understandable) error. The next line printed after
that warning line is usually the current module list, and that printk
does not have a log-level marker - resulting in one long mixed-up line.
Adding this loglevel marker will now avoid this unreadable mess.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's theoretically possible that there are exception table entries
which point into the (freed) init text of modules. These could cause
future problems if other modules get loaded into that memory and cause
an exception as we'd see the wrong fixup. The only case I know of is
kvm-intel.ko (when CONFIG_CC_OPTIMIZE_FOR_SIZE=n).
Amerigo fixed this long-standing FIXME in the x86 version, but this
patch is more general.
This implements trim_init_extable(); most archs are simple since they
use the standard lib/extable.c sort code. Alpha and IA64 use relative
addresses in their fixups, so thier trimming is a slight variation.
Sparc32 is unique; it doesn't seem to define ARCH_HAS_SORT_EXTABLE,
yet it defines its own sort_extable() which overrides the one in lib.
It doesn't sort, so we have to mark deleted entries instead of
actually trimming them.
Inspired-by: Amerigo Wang <amwang@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-alpha@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
* 'for-linus' of git://linux-arm.org/linux-2.6:
kmemleak: Add the corresponding MAINTAINERS entry
kmemleak: Simple testing module for kmemleak
kmemleak: Enable the building of the memory leak detector
kmemleak: Remove some of the kmemleak false positives
kmemleak: Add modules support
kmemleak: Add kmemleak_alloc callback from alloc_large_system_hash
kmemleak: Add the vmalloc memory allocation/freeing hooks
kmemleak: Add the slub memory allocation/freeing hooks
kmemleak: Add the slob memory allocation/freeing hooks
kmemleak: Add the slab memory allocation/freeing hooks
kmemleak: Add documentation on the memory leak detector
kmemleak: Add the base support
Manual conflict resolution (with the slab/earlyboot changes) in:
drivers/char/vt.c
init/main.c
mm/slab.c
This patch handles the kmemleak operations needed for modules loading so
that memory allocations from inside a module are properly tracked.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The hooks in the module code for the function tracer must be called
before any of that module code runs. The function tracer hooks
modify the module (replacing calls to mcount to nops). If the code
is executed while the change occurs, then the CPU can take a GPF.
To handle the above with a bit of paranoia, I originally implemented
the hooks as calls directly from the module code.
After examining the notifier calls, it looks as though the start up
notify is called before any of the module's code is executed. This makes
the use of the notify safe with ftrace.
Only the startup notify is required to be "safe". The shutdown simply
removes the entries from the ftrace function list, and does not modify
any code.
This change has another benefit. It removes a issue with a reverse dependency
in the mutexes of ftrace_lock and module_mutex.
[ Impact: fix lock dependency bug, cleanup ]
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit 3d43321b70 ("modules: sysctl to
block module loading") introduces a modules_disabled variable that is
only defined if CONFIG_MODULE_UNLOAD is enabled, despite being used in
other places. This moves it up and fixes up the build.
CC kernel/module.o
kernel/module.c: In function 'sys_init_module':
kernel/module.c:2401: error: 'modules_disabled' undeclared (first use in this function)
kernel/module.c:2401: error: (Each undeclared identifier is reported only once
kernel/module.c:2401: error: for each function it appears in.)
make[1]: *** [kernel/module.o] Error 1
make: *** [kernel/module.o] Error 2
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: James Morris <jmorris@namei.org>
Impact: allow modules to add TRACE_EVENTS on load
This patch adds the final hooks to allow modules to use the TRACE_EVENT
macro. A notifier and a data structure are used to link the TRACE_EVENTs
defined in the module to connect them with the ftrace event tracing system.
It also adds the necessary automated clean ups to the trace events when a
module is removed.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Several drivers use asynchronous work to do device discovery, and we
synchronize with them in the compiled-in case before we actually try to
mount root filesystems etc.
However, when compiled as modules, that synchronization is missing - the
module loading completes, but the driver hasn't actually finished
probing for devices, and that means that any user mode that expects to
use the devices after the 'insmod' is now potentially broken.
We already saw one case of a similar issue in the ACPI battery code,
where the kernel itself expected the module to be all done, and unmapped
the init memory - but the async device discovery was still running.
That got hacked around by just removing the "__init" (see commit
5d38258ec0 "ACPI battery: fix async boot
oops"), but the real fix is to just make the module loading wait for all
async work to be completed.
It will slow down module loading, but since common devices should be
built in anyway, and since the bug is really annoying and hard to handle
from user space (and caused several S3 resume regressions), the simple
fix to wait is the right one.
This fixes at least
http://bugzilla.kernel.org/show_bug.cgi?id=13063
but probably a few other bugzilla entries too (12936, for example), and
is confirmed to fix Rafael's storage driver breakage after resume bug
report (no bugzilla entry).
We should also be able to now revert that ACPI battery fix.
Reported-and-tested-by: Rafael J. Wysocki <rjw@suse.com>
Tested-by: Heinz Diehl <htd@fancy-poultry.org>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 9cb610d8e3.
This was an impressively stupid patch. Firstly, we reset the SHF_ALLOC
flag lower down in the same function, so the patch was useless. Even
better, find_sec() ignores sections with SHF_ALLOC not set, so
it breaks CONFIG_MODVERSIONS=y with CONFIG_MODULE_FORCE_LOAD=n, which
refuses to load the module since it can't find the __versions section.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
tracing, net: fix net tree and tracing tree merge interaction
tracing, powerpc: fix powerpc tree and tracing tree interaction
ring-buffer: do not remove reader page from list on ring buffer free
function-graph: allow unregistering twice
trace: make argument 'mem' of trace_seq_putmem() const
tracing: add missing 'extern' keywords to trace_output.h
tracing: provide trace_seq_reserve()
blktrace: print out BLK_TN_MESSAGE properly
blktrace: extract duplidate code
blktrace: fix memory leak when freeing struct blk_io_trace
blktrace: fix blk_probes_ref chaos
blktrace: make classic output more classic
blktrace: fix off-by-one bug
blktrace: fix the original blktrace
blktrace: fix a race when creating blk_tree_root in debugfs
blktrace: fix timestamp in binary output
tracing, Text Edit Lock: cleanup
tracing: filter fix for TRACE_EVENT_FORMAT events
ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
x86: kretprobe-booster interrupt emulation code fix
...
Fix up trivial conflicts in
arch/parisc/include/asm/ftrace.h
include/linux/memory.h
kernel/extable.c
kernel/module.c
Implement a sysctl file that disables module-loading system-wide since
there is no longer a viable way to remove CAP_SYS_MODULE after the system
bounding capability set was removed in 2.6.25.
Value can only be set to "1", and is tested only if standard capability
checks allow CAP_SYS_MODULE. Given existing /dev/mem protections, this
should allow administrators a one-way method to block module loading
after initial boot-time module loading has finished.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Impact: minor cleanup.
I'm not going to neaten anyone else's code, but I'm happy to clean up
my own.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Kay Sievers <kay.sievers@vrfy.org> discovered that boot times are slowed
by about half a second because all the stop_machine_create() calls,
and he only probes about 40 modules (I have 125 loaded on this laptop).
We only do stop_machine_create() so we can unlink the module if
something goes wrong, but it's overkill (and buggy anyway: if
stop_machine_create() fails we still call stop_machine_destroy()).
Since we are only protecting against kallsyms (esp. oops) walking the
list, synchronize_sched() is sufficient (synchronize_rcu() is probably
sufficient, but we're not in a hurry).
Kay says of this patch:
... no module takes more than 40 millisecs to link now, most of
them are between 3 and 8 millisecs.
That looks very different to the numbers without this patch
and the otherwise same setup, where we get heavy noise in the
traces and many delays of up to 200 millisecs until linking,
most of them taking 30+ millisecs.
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
