Commit Graph

298 Commits

Author SHA1 Message Date
Mathieu Desnoyers
b75ef8b44b Tracepoint: Dissociate from module mutex
Copy the information needed from struct module into a local module list
held within tracepoint.c from within the module coming/going notifier.

This vastly simplifies locking of tracepoint registration /
unregistration, because we don't have to take the module mutex to
register and unregister tracepoints anymore. Steven Rostedt ran into
dependency problems related to modules mutex vs kprobes mutex vs ftrace
mutex vs tracepoint mutex that seems to be hard to fix without removing
this dependency between tracepoint and module mutex. (note: it should be
investigated whether kprobes could benefit of being dissociated from the
modules mutex too.)

This also fixes module handling of tracepoint list iterators, because it
was expecting the list to be sorted by pointer address. Given we have
control on our own list now, it's OK to sort this list which has
tracepoints as its only purpose. The reason why this sorting is required
is to handle the fact that seq files (and any read() operation from
user-space) cannot hold the tracepoint mutex across multiple calls, so
list entries may vanish between calls. With sorting, the tracepoint
iterator becomes usable even if the list don't contain the exact item
pointed to by the iterator anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Jason Baron <jbaron@redhat.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20110810191839.GC8525@Krystal
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-08-10 20:38:14 -04:00
Kay Sievers
88bfa32479 module: add /sys/module/<name>/uevent files
Userspace wants to manage module parameters with udev rules.
This currently only works for loaded modules, but not for
built-in ones.

To allow access to the built-in modules we need to
re-trigger all module load events that happened before any
userspace was running. We already do the same thing for all
devices, subsystems(buses) and drivers.

This adds the currently missing /sys/module/<name>/uevent files
to all module entries.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (split & trivial fix)
2011-07-24 22:06:04 +09:30
Kay Sievers
4befb026cf module: change attr callbacks to take struct module_kobject
This simplifies the next patch, where we have an attribute on a
builtin module (ie. module == NULL).

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (split into 2)
2011-07-24 22:06:04 +09:30
Jonas Bonn
74e08fcf7b modules: add default loader hook implementations
The module loader code allows architectures to hook into the code by
providing a small number of entry points that each arch must implement.
This patch provides __weakly linked generic implementations of these
entry points for architectures that don't need to do anything special.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-07-24 22:06:04 +09:30
Linus Torvalds
1f3a8e093f Merge branch 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6
* 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (970 commits)
  staging: usbip: replace usbip_u{dbg,err,info} and printk with dev_ and pr_
  staging:iio: Trivial kconfig reorganization and uniformity improvements.
  staging:iio:documenation partial update.
  staging:iio: use pollfunc allocation helpers in remaining drivers.
  staging:iio:max1363 misc cleanups and use of for_each_bit_set to simplify event code spitting out.
  staging:iio: implement an iio_info structure to take some of the constant elements out of iio_dev.
  staging:iio:meter:ade7758: Use private data space from iio_allocate_device
  staging:iio:accel:lis3l02dq make write_reg_8 take value not a pointer to value.
  staging:iio: ring core cleanups + check if read_last available in lis3l02dq
  staging:iio:core cleanup: squash tiny wrappers and use dev_set_name to handle creation of event interface name.
  staging:iio: poll func allocation clean up.
  staging:iio:ad7780 trivial unused header cleanup.
  staging:iio:adc: AD7780: Use private data space from iio_allocate_device + trivial fixes
  staging:iio:adc:AD7780: Convert to new channel registration method
  staging:iio:adc: AD7606: Drop dev_data in favour of iio_priv()
  staging:iio:adc: AD7606: Consitently use indio_dev
  staging:iio: Rip out helper for software rings.
  staging:iio:adc:AD7298: Use private data space from iio_allocate_device
  staging:iio: rationalization of different buffer implementation hooks.
  staging:iio:imu:adis16400 avoid allocating rx, tx, and state separately from iio_dev.
  ...

Fix up trivial conflicts in
 - drivers/staging/intel_sst/intelmid.c: patches applied in both branches
 - drivers/staging/rt2860/common/cmm_data_{pci,usb}.c: removed vs spelling
 - drivers/staging/usbip/vhci_sysfs.c: trivial header file inclusion
2011-05-23 12:49:28 -07:00
Alessio Igor Bogani
9d63487f86 module: Use binary search in lookup_symbol()
The function is_exported() with its helper function lookup_symbol() are used to
verify if a provided symbol is effectively exported by the kernel or by the
modules. Now that both have their symbols sorted we can replace a linear search
with a binary search which provide a considerably speed-up.

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:27 +09:30
Alessio Igor Bogani
403ed27846 module: Use the binary search for symbols resolution
Takes advantage of the order and locates symbols using binary search.

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Dirk Behme <dirk.behme@googlemail.com>
2011-05-19 16:55:27 +09:30
Rusty Russell
de4d8d5346 module: each_symbol_section instead of each_symbol
Instead of having a callback function for each symbol in the kernel,
have a callback for each array of symbols.

This eases the logic when we move to sorted symbols and binary search.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
2011-05-19 16:55:26 +09:30
Jan Glauber
01526ed083 module: split unset_section_ro_nx function.
Split the unprotect function into a function per section to make
the code more readable and add the missing static declaration.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:26 +09:30
Jan Glauber
448694a1d5 module: undo module RONX protection correctly.
While debugging I stumbled over two problems in the code that protects module
pages.

First issue is that disabling the protection before freeing init or unload of
a module is not symmetric with the enablement. For instance, if pages are set
to RO the page range from module_core to module_core + core_ro_size is
protected. If a module is unloaded the page range from module_core to
module_core + core_size is set back to RW.
So pages that were not set to RO are also changed to RW.
This is not critical but IMHO it should be symmetric.

Second issue is that while set_memory_rw & set_memory_ro are used for
RO/RW changes only set_memory_nx is involved for NX/X. One would await that
the inverse function is called when the NX protection should be removed,
which is not the case here, unless I'm missing something.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:26 +09:30
Jan Glauber
4d10380e72 module: zero mod->init_ro_size after init is freed.
Reset mod->init_ro_size to zero after the init part of a module is unloaded.
Otherwise we need to check if module->init is NULL in the unprotect functions
in the next patch.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:26 +09:30
Daniel J Blueman
5d05c70849 minor ANSI prototype sparse fix
Fix function prototype to be ANSI-C compliant, consistent with other
function prototypes, addressing a sparse warning.

Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:25 +09:30
Roland Vossen
7816c45bf1 modules: Enabled dynamic debugging for staging modules
Driver modules from the staging directory are marked 'tainted'
by module.c. Subsequently, tainted modules are denied dynamic
debugging. This is unwanted behavior, since staging modules should
be able to use the dynamic debugging mechanism.

Please merge this also into the staging-linus branch.

Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25 16:45:22 -07:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Kees Cook
9f36e2c448 printk: use %pK for /proc/kallsyms and /proc/modules
In an effort to reduce kernel address leaks that might be used to help
target kernel privilege escalation exploits, this patch uses %pK when
displaying addresses in /proc/kallsyms, /proc/modules, and
/sys/module/*/sections/*.

Note that this changes %x to %p, so some legitimately 0 values in
/proc/kallsyms would have changed from 00000000 to "(null)".  To avoid
this, "(null)" is not used when using the "K" format.  Anything that was
already successfully parsing "(null)" in addition to full hex digits
should have no problem with this change.  (Thanks to Joe Perches for the
suggestion.) Due to the %x to %p, "void *" casts are needed since these
addresses are already "unsigned long" everywhere internally, due to their
starting life as ELF section offsets.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Cc: Eugene Teo <eugene@redhat.com>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:12 -07:00
Mathieu Desnoyers
6549864629 tracepoints: Fix section alignment using pointer array
Make the tracepoints more robust, making them solid enough to handle compiler
changes by not relying on anything based on compiler-specific behavior with
respect to structure alignment. Implement an approach proposed by David Miller:
use an array of const pointers to refer to the individual structures, and export
this pointer array through the linker script rather than the structures per se.
It will consume 32 extra bytes per tracepoint (24 for structure padding and 8
for the pointers), but are less likely to break due to compiler changes.

History:

commit 7e066fb8 tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()
added the aligned(32) type and variable attribute to the tracepoint structures
to deal with gcc happily aligning statically defined structures on 32-byte
multiples.

One attempt was to use a 8-byte alignment for tracepoint structures by applying
both the variable and type attribute to tracepoint structures definitions and
declarations. It worked fine with gcc 4.5.1, but broke with gcc 4.4.4 and 4.4.5.

The reason is that the "aligned" attribute only specify the _minimum_ alignment
for a structure, leaving both the compiler and the linker free to align on
larger multiples. Because tracepoint.c expects the structures to be placed as an
array within each section, up-alignment cause NULL-pointer exceptions due to the
extra unexpected padding.

(this patch applies on top of -tip)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <20110126222622.GA10794@Krystal>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-02-03 09:28:46 -05:00
Steven Rostedt
94462ad3b1 module: Move RO/NX module protection to after ftrace module update
The commit:

84e1c6bb38
x86: Add RO/NX protection for loadable kernel modules

Broke the function tracer with this output:

------------[ cut here ]------------
WARNING: at kernel/trace/ftrace.c:1014 ftrace_bug+0x114/0x171()
Hardware name: Precision WorkStation 470
Modules linked in: i2c_core(+)
Pid: 86, comm: modprobe Not tainted 2.6.37-rc2+ #68
Call Trace:
 [<ffffffff8104e957>] warn_slowpath_common+0x85/0x9d
 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core]
 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core]
 [<ffffffff8104e989>] warn_slowpath_null+0x1a/0x1c
 [<ffffffff810a9dfe>] ftrace_bug+0x114/0x171
 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core]
 [<ffffffff810aa0db>] ftrace_process_locs+0x1ae/0x274
 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core]
 [<ffffffff810aa29e>] ftrace_module_notify+0x39/0x44
 [<ffffffff814405cf>] notifier_call_chain+0x37/0x63
 [<ffffffff8106e054>] __blocking_notifier_call_chain+0x46/0x5b
 [<ffffffff8106e07d>] blocking_notifier_call_chain+0x14/0x16
 [<ffffffff8107ffde>] sys_init_module+0x73/0x1f3
 [<ffffffff8100acf2>] system_call_fastpath+0x16/0x1b
---[ end trace 2aff4f4ca53ec746 ]---
ftrace faulted on writing [<ffffffffa00026db>]
__process_new_adapter+0x7/0x34 [i2c_core]

The cause was that the module text was set to read only before ftrace
could convert the calls to mcount to nops. Thus, the conversions failed
due to not being able to write to the text locations.

The simple fix is to move setting the module to read only after the
module notifiers are called (where ftrace sets the module mcounts to nops).

Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-12-23 09:56:00 -05:00
Ingo Molnar
26e20a108c Merge commit 'v2.6.37-rc7' into x86/security 2010-12-23 09:48:41 +01:00
matthieu castet
84e1c6bb38 x86: Add RO/NX protection for loadable kernel modules
This patch is a logical extension of the protection provided by
CONFIG_DEBUG_RODATA to LKMs. The protection is provided by
splitting module_core and module_init into three logical parts
each and setting appropriate page access permissions for each
individual section:

 1. Code: RO+X
 2. RO data: RO+NX
 3. RW data: RW+NX

In order to achieve proper protection, layout_sections() have
been modified to align each of the three parts mentioned above
onto page boundary. Next, the corresponding page access
permissions are set right before successful exit from
load_module(). Further, free_module() and sys_init_module have
been modified to set module_core and module_init as RW+NX right
before calling module_free().

By default, the original section layout and access flags are
preserved. When compiled with CONFIG_DEBUG_SET_MODULE_RONX=y,
the patch will page-align each group of sections to ensure that
each page contains only one type of content and will enforce
RO/NX for each group of pages.

  -v1: Initial proof-of-concept patch.
  -v2: The patch have been re-written to reduce the number of #ifdefs
       and to make it architecture-agnostic. Code formatting has also
       been corrected.
  -v3: Opportunistic RO/NX protection is now unconditional. Section
       page-alignment is enabled when CONFIG_DEBUG_RODATA=y.
  -v4: Removed most macros and improved coding style.
  -v5: Changed page-alignment and RO/NX section size calculation
  -v6: Fixed comments. Restricted RO/NX enforcement to x86 only
  -v7: Introduced CONFIG_DEBUG_SET_MODULE_RONX, added
       calls to set_all_modules_text_rw() and set_all_modules_text_ro()
       in ftrace
  -v8: updated for compatibility with linux 2.6.33-rc5
  -v9: coding style fixes
 -v10: more coding style fixes
 -v11: minor adjustments for -tip
 -v12: minor adjustments for v2.6.35-rc2-tip
 -v13: minor adjustments for v2.6.37-rc1-tip

Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com>
Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dave Jones <davej@redhat.com>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4CE2F914.9070106@free.fr>
[ minor cleanliness edits, -v14: build failure fix ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18 13:32:56 +01:00
Steven Rostedt
13b9b6e746 tracing: Fix module use of trace_bprintk()
On use of trace_printk() there's a macro that determines if the format
is static or a variable. If it is static, it defaults to __trace_bprintk()
otherwise it uses __trace_printk().

A while ago, Lai Jiangshan added __trace_bprintk(). In that patch, we
discussed a way to allow modules to use it. The difference between
__trace_bprintk() and __trace_printk() is that for faster processing,
just the format and args are stored in the trace instead of running
it through a sprintf function. In order to do this, the format used
by the __trace_bprintk() had to be persistent.

See commit 1ba28e02a1

The problem comes with trace_bprintk() where the module is unloaded.
The pointer left in the buffer is still pointing to the format.

To solve this issue, the formats in the module were copied into kernel
core. If the same format was used, they would use the same copy (to prevent
memory leak). This all worked well until we tried to merge everything.

At the time this was written, Lai Jiangshan, Frederic Weisbecker,
Ingo Molnar and myself were all touching the same code. When this was
merged, we lost the part of it that was in module.c. This kept out the
copying of the formats and unloading the module could cause bad pointers
left in the ring buffer.

This patch adds back (with updates required for current kernel) the
module code that sets up the necessary pointers.

Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-11-10 22:19:24 -05:00
Michał Mirosław
abbce906d0 (trivial) Fix compiler warning in kernel/modules.c
Building with CONFIG_KALLSYMS=n gives following warning:

/mnt/src/linux-git/kernel/module.c: In function ‘post_relocation’:
/mnt/src/linux-git/kernel/module.c:2534:2: warning: passing argument 2 of ‘add_kallsyms’ discards qualifiers from pointer target type
/mnt/src/linux-git/kernel/module.c:2038:13: note: expected ‘struct load_info *’ but argument is of type ‘const struct load_info *’

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-27 20:33:05 +10:30
Ingo Molnar
7cd2541cf2 Merge commit 'v2.6.36-rc7' into perf/core
Conflicts:
	arch/x86/kernel/module.c

Merge reason: Resolve the conflict, pick up fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-08 10:46:27 +02:00
Linus Torvalds
5336377d62 modules: Fix module_bug_list list corruption race
With all the recent module loading cleanups, we've minimized the code
that sits under module_mutex, fixing various deadlocks and making it
possible to do most of the module loading in parallel.

However, that whole conversion totally missed the rather obscure code
that adds a new module to the list for BUG() handling.  That code was
doubly obscure because (a) the code itself lives in lib/bugs.c (for
dubious reasons) and (b) it gets called from the architecture-specific
"module_finalize()" rather than from generic code.

Calling it from arch-specific code makes no sense what-so-ever to begin
with, and is now actively wrong since that code isn't protected by the
module loading lock any more.

So this commit moves the "module_bug_{finalize,cleanup}()" calls away
from the arch-specific code, and into the generic code - and in the
process protects it with the module_mutex so that the list operations
are now safe.

Future fixups:
 - move the module list handling code into kernel/module.c where it
   belongs.
 - get rid of 'module_bug_list' and just use the regular list of modules
   (called 'modules' - imagine that) that we already create and maintain
   for other reasons.

Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-05 11:29:27 -07:00
Jason Baron
bf5438fca2 jump label: Base patch for jump label
base patch to implement 'jump labeling'. Based on a new 'asm goto' inline
assembly gcc mechanism, we can now branch to labels from an 'asm goto'
statment. This allows us to create a 'no-op' fastpath, which can subsequently
be patched with a jump to the slowpath code. This is useful for code which
might be rarely used, but which we'd like to be able to call, if needed.
Tracepoints are the current usecase that these are being implemented for.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com>

[ cleaned up some formating ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-09-22 16:29:41 -04:00
Rusty Russell
51f3d0f474 module: cleanup comments, remove noinline
On my (32-bit x86) machine, sys_init_module() uses 124 bytes of stack
once load_module() is inlined.

This effectively reverts ffb4ba76 which inlined it due to stack
pressure.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:13 +09:30
Rusty Russell
811d66a0e1 module: group post-relocation functions into post_relocation()
This simply hoists more code out of load_module; we also put the
identification of the extable and dynamic debug table in with the
others in find_module_sections().

We move the taint check to the actual add/remove of the dynamic debug
info: this is certain (find_module_sections is too early).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yehuda Sadeh <yehuda@hq.newdream.net>
2010-08-05 12:59:13 +09:30
Rusty Russell
6526c534b2 module: move module args strndup_user to just before use
Instead of copying and allocating the args and storing it in
load_info, we can just allocate them right before we need them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:12 +09:30
Rusty Russell
49668688dd module: pass load_info into other functions
Pass the struct load_info into all the other functions in module
loading.  This neatens things and makes them more consistent.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:10 +09:30
Rusty Russell
36b0360d17 module: fix sysfs cleanup for !CONFIG_SYSFS
Restore the stub module_remove_modinfo_attrs, remove the now-unused
!CONFIG_SYSFS module_sysfs_init.

Also, rename mod_kobject_remove() to mod_sysfs_teardown() as
it is the logical counterpart to mod_sysfs_setup now.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:10 +09:30
Rusty Russell
8f6d037815 module: sysfs cleanup
We change the sysfs functions to take struct load_info, and call
them all in mod_sysfs_setup().

We also clean up the #ifdefs a little.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:09 +09:30
Rusty Russell
d913188c75 module: layout_and_allocate
layout_and_allocate() does everything up to and including the final
struct module placement inside the allocated module memory.  We have
to store the symbol layout information in our struct load_info though.

This avoids the nasty code we had before where 'mod' pointed first
to the version inside the temporary allocation containing the entire
file, then later was moved to point to the real struct module: now
the main code only ever sees the final module address.

(Includes fix for the Tony Luck-found Linus-diagnosed failure path
 error).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:09 +09:30
Rusty Russell
511ca6ae43 module: fix crash in get_ksymbol() when oopsing in module init
Andrew had the sole pleasure of tickling this bug in linux-next; when we set
up "info->strtab" it's pointing into the temporary copy of the module.  For
most uses that is fine, but kallsyms keeps a pointer around during module
load (inside mod->strtab).

If we oops for some reason inside a module's init function, kallsyms will use
the mod->strtab pointer into the now-freed temporary module copy.

(Later oopses work fine: after init we overwrite mod->strtab to point to a
 compacted core-only strtab).

Reported-by: Andrew "Grumpy" Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty "Buggy" Russell <rusty@rustcorp.com.au>
Tested-by: Andrew "Happy" Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:08 +09:30
Rusty Russell
eded41c1c6 module: kallsyms functions take struct load_info
Simple refactor causes us to lift struct definition to top of file.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:08 +09:30
Rusty Russell
d6df72a06e module: refactor out section header rewriting: FIX modversions
We can't do the find_sec after removing the SHF_ALLOC flags; it won't
find the sections.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:07 +09:30
Rusty Russell
8b5f61a795 module: refactor out section header rewriting
Put all the "rewrite and check section headers" in one place.  This
adds another iteration over the sections, but it's far clearer.  We
iterate once for every find_section() so we already iterate over many
times.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:06 +09:30
Linus Torvalds
3264d3f9dd module: add load_info
Btw, here's a patch that _looks_ large, but it really pretty trivial, and
sets things up so that it would be way easier to split off pieces of the
module loading.

The reason it looks large is that it creates a "module_info" structure
that contains all the module state that we're building up while loading,
instead of having individual variables for all the indices etc.

So the patch ends up being large, because every "symindex" access instead
becomes "info.index.sym" etc. That may be a few characters longer, but it
then means that we can just pass a pointer to that "info" structure
around. and let all the pieces fill it in very naturally.

As an example of that, the patch also moves the initialization of all
those convenience variables into a "setup_module_info()" function. And at
this point it really does become very natural to start to peel off some of
the error labels and move them into the helper functions - now the
"truncated" case is gone, and is handled inside that setup function
instead.

So maybe you don't like this approach, and it does make the variable
accesses a bit longer, but I don't think unreadably so. And the patch
really does look big and scary, but there really should be absolutely no
semantic changes - most of it was a trivial and mindless rename.

In fact, it was so mindless that I on purpose kept the existing helper
functions looking like this:

-       err = check_modinfo(mod, sechdrs, infoindex, versindex);
+       err = check_modinfo(mod, info.sechdrs, info.index.info, info.index.vers);

rather than changing them to just take the "info" pointer. IOW, a second
phase (if you think the approach is ok) would change that calling
convention to just do

	err = check_modinfo(mod, &info);

(and same for "layout_sections()", "layout_symtabs()" etc.) Similarly,
while right now it makes things _look_ bigger, with things like this:

	versindex = find_sec(hdr, sechdrs, secstrings, "__versions");

becoming

	info->index.vers = find_sec(info->hdr, info->sechdrs, info->secstrings, "__versions");

in the new "setup_module_info()" function, that's again just a result of
it being a search-and-replace patch. By using the 'info' pointer, we could
just change the 'find_sec()' interface so that it ends up being

	info->index.vers = find_sec(info, "__versions");

instead, and then we'd actually have a shorter and more readable line. So
for a lot of those mindless variable name expansions there's would be room
for separate cleanups.

I didn't move quite everything in there - if we do this to layout_symtabs,
for example, we'd want to move the percpu, symoffs, stroffs, *strmap
variables to be fields in that module_info structure too. But that's a
much smaller patch, I moved just the really core stuff that is currently
being set up and used in various parts.

But even in this rough form, it removes close to 70 lines from that
function (but adds 22 lines overall, of course - the structure definition,
the helper function declarations and call-sites etc etc).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:06 +09:30
Linus Torvalds
44032e6316 module: reduce stack usage for each_symbol()
And now that I'm looking at that call-chain (to see if it would make sense
to use some other more specific lock - doesn't look like it: all the
readers are using RCU and this is the only writer), I also give you this
trivial one-liner. It changes each_symbol() to not put that constant array
on the stack, resulting in changing

        movq    $C.388.31095, %rsi      #, tmp85
        subq    $376, %rsp      #,
        movq    %rdi, %rbx      # fn, fn
        leaq    -208(%rbp), %rdi        #, tmp84
        movq    %rbx, %rdx      # fn,
        rep movsl
        xorl    %esi, %esi      #
        leaq    -208(%rbp), %rdi        #, tmp87
        movq    %r12, %rcx      # data,
        call    each_symbol_in_section.clone.0  #

into

        xorl    %esi, %esi      #
        subq    $216, %rsp      #,
        movq    %rdi, %rbx      # fn, fn
        movq    $arr.31078, %rdi        #,
        call    each_symbol_in_section.clone.0  #

which is not so much about being obviously shorter and simpler because we
don't unnecessarily copy that constant array around onto the stack, but
also about having a much smaller stack footprint (376 vs 216 bytes - see
the update of 'rsp').

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:06 +09:30
Rusty Russell
22e268ebec module: refactor load_module part 5
1) Extract out the relocation loop into apply_relocations
2) Extract license and version checks into check_module_license_and_versions
3) Extract icache flushing into flush_module_icache
4) Move __obsparm warning into find_module_sections
5) Move license setting into check_modinfo.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:05 +09:30
Rusty Russell
9f85a4bbb1 module: refactor load_module part 4
Allocate references inside module_unload_init(), clean up inside
module_unload_free().

This version fixed to do allocation before __this_cpu_write, thanks to
bug reports from linux-next from Dave Young <hidave.darkstar@gmail.com>
and Stephen Rothwell <sfr@canb.auug.org.au>.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:05 +09:30
Rusty Russell
40dd2560ec module: refactor load_module part 3
Extract out the allocation and copying in from userspace, and the
first set of modinfo checks.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:04 +09:30
Linus Torvalds
65b8a9b4d5 module: refactor load_module part 2
Here's a second one. It's slightly less trivial - since we now have error
cases - and equally untested so it may well be totally broken. But it also
cleans up a bit more, and avoids one of the goto targets, because the
"move_module()" helper now does both allocations or none.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:03 +09:30
Linus Torvalds
f91a13bb99 module: refactor load_module
I'd start from the trivial stuff. There's a fair amount of straight-line
code that just makes the function hard to read just because you have to
page up and down so far. Some of it is trivial to just create a helper
function for.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-08-05 12:59:02 +09:30
Eric Dumazet
2409e74278 module: module_unload_init() cleanup
No need to clear mod->refptr in module_unload_init(), since
alloc_percpu() already clears allocated chunks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
2010-08-05 12:59:02 +09:30
Jason Baron
b82bab4bbe dynamic debug: move ddebug_remove_module() down into free_module()
The command

	echo "file ec.c +p" >/sys/kernel/debug/dynamic_debug/control

causes an oops.

Move the call to ddebug_remove_module() down into free_module().  In this
way it should be called from all error paths.  Currently, we are missing
the remove if the module init routine fails.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Reported-by: Thomas Renninger <trenn@suse.de>
Tested-by: Thomas Renninger <trenn@suse.de>
Cc: <stable@kernel.org>		[2.6.32+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-27 14:32:06 -07:00
Yehuda Sadeh
ff49d74ad3 module: initialize module dynamic debug later
We should initialize the module dynamic debug datastructures
only after determining that the module is not loaded yet. This
fixes a bug that introduced in 2.6.35-rc2, where when a trying
to load a module twice, we also load it's dynamic printing data
twice which causes all sorts of nasty issues. Also handle
the dynamic debug cleanup later on failure.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-04 20:17:22 -07:00
Rusty Russell
9bea7f2395 module: fix bne2 "gave up waiting for init of module libcrc32c"
Problem: it's hard to avoid an init routine stumbling over a
request_module these days.  And it's not clear it's always a bad idea:
for example, a module like kvm with dynamic dependencies on kvm-intel
or kvm-amd would be neater if it could simply request_module the right
one.

In this particular case, it's libcrc32c:

	libcrc32c_mod_init
	 crypto_alloc_shash
	  crypto_alloc_tfm
	   crypto_find_alg
	    crypto_alg_mod_lookup
	     crypto_larval_lookup
	      request_module

If another module is waiting inside resolve_symbol() for libcrc32c to
finish initializing (ie. bne2 depends on libcrc32c) then it does so
holding the module lock, and our request_module() can't make progress
until that is released.

Waiting inside resolve_symbol() without the lock isn't all that hard:
we just need to pass the -EBUSY up the call chain so we can sleep
where we don't hold the lock.  Error reporting is a bit trickier: we
need to copy the name of the unfinished module before releasing the
lock.

Other notes:
1) This also fixes a theoretical issue where a weak dependency would allow
   symbol version mismatches to be ignored.
2) We rename use_module to ref_module to make life easier for the only
   external user (the out-of-tree ksplice patches).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tim Abbot <tabbott@ksplice.com>
Tested-by: Brandon Philips <bphilips@suse.de>
2010-06-05 11:17:37 +09:30
Rusty Russell
be593f4ce4 module: verify_export_symbols under the lock
It disabled preempt so it was "safe", but nothing stops another module
slipping in before this module is added to the global list now we don't
hold the lock the whole time.

So we check this just after we check for duplicate modules, and just
before we put the module in the global list.

(find_symbol finds symbols in coming and going modules, too).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-06-05 11:17:37 +09:30
Linus Torvalds
3bafeb6247 module: move find_module check to end
I think Rusty may have made the lock a bit _too_ finegrained there, and
didn't add it to some places that needed it. It looks, for example, like
PATCH 1/2 actually drops the lock in places where it's needed
("find_module()" is documented to need it, but now load_module() didn't
hold it at all when it did the find_module()).

Rather than adding a new "module_loading" list, I think we should be able
to just use the existing "modules" list, and just fix up the locking a
bit.

In fact, maybe we could just move the "look up existing module" a bit
later - optimistically assuming that the module doesn't exist, and then
just undoing the work if it turns out that we were wrong, just before
adding ourselves to the list.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-06-05 11:17:37 +09:30
Rusty Russell
75676500f8 module: make locking more fine-grained.
Kay Sievers <kay.sievers@vrfy.org> reports that we still have some
contention over module loading which is slowing boot.

Linus also disliked a previous "drop lock and regrab" patch to fix the
bne2 "gave up waiting for init of module libcrc32c" message.

This is more ambitious: we only grab the lock where we need it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Brandon Philips <brandon@ifup.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-05 11:17:36 +09:30
Rusty Russell
6407ebb271 module: Make module sysfs functions private.
These were placed in the header in ef665c1a06 to get the various
SYSFS/MODULE config combintations to compile.

That may have been necessary then, but it's not now.  These functions
are all local to module.c.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
2010-06-05 11:17:36 +09:30