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  1. 22 11月, 2010 1 次提交
  3. 12 11月, 2010 1 次提交
    • N
      radix-tree: fix RCU bug · 27d20fdd
      由 Nick Piggin 提交于 
      Salman Qazi describes the following radix-tree bug:

In the following case, we get can get a deadlock:

0.  The radix tree contains two items, one has the index 0.
1.  The reader (in this case find_get_pages) takes the rcu_read_lock.
2.  The reader acquires slot(s) for item(s) including the index 0 item.
3.  The non-zero index item is deleted, and as a consequence the other item is
    moved to the root of the tree. The place where it used to be is queued for
    deletion after the readers finish.
3b. The zero item is deleted, removing it from the direct slot, it remains in
    the rcu-delayed indirect node.
4.  The reader looks at the index 0 slot, and finds that the page has 0 ref
    count
5.  The reader looks at it again, hoping that the item will either be freed or
    the ref count will increase. This never happens, as the slot it is looking
    at will never be updated. Also, this slot can never be reclaimed because
    the reader is holding rcu_read_lock and is in an infinite loop.

The fix is to re-use the same "indirect" pointer case that requires a slot
lookup retry into a general "retry the lookup" bit.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>
Reported-by: NSalman Qazi <sqazi@google.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      27d20fdd
  5. 27 10月, 2010 16 次提交
  7. 23 10月, 2010 4 次提交
    • R
      kobject: Introduce kset_find_obj_hinted. · c25d1dfb
      由 Robin Holt 提交于 
      One call chain getting to kset_find_obj is:
  link_mem_sections()
    find_mem_section()
      kset_find_obj()

This is done during boot.  The memory sections were added in a linearly
increasing order and link_mem_sections tends to utilize them in that
same linear order.

Introduce a kset_find_obj_hinted which is passed the result of the
previous kset_find_obj which it uses for a quick "is the next object
our desired object" check before falling back to the old behavior.
Signed-off-by: NRobin Holt <holt@sgi.com>
To: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      c25d1dfb
    • T
      Dynamic Debug: Initialize dynamic debug earlier via arch_initcall · 6a5c083d
      由 Thomas Renninger 提交于 
      Having the ddebug_query= boot parameter it makes sense to set up
dynamic debug as soon as possible.

I expect sysfs files cannot be set up via an arch_initcall, because
this one is even before fs_initcall. Therefore I splitted the
dynamic_debug_init function into an early one and a later one providing
/sys/../dynamic_debug/control file.

Possibly dynamic_debug can be initialized even earlier, not sure whether
this still makes sense then. I picked up arch_initcall as it covers
quite a lot already.

Dynamic debug needs to allocate memory, therefore it's not easily possible to
set it up even before the command line gets parsed.
Therefore the boot param query string is stored in a temp string which is
applied when dynamic debug gets set up.

This has been tested with ddebug_query="file ec.c +p"
and I could retrieve pr_debug() messages early at boot during ACPI setup:
ACPI: EC: Look up EC in DSDT
ACPI: EC: ---> status = 0x08
ACPI: EC: transaction start
ACPI: EC: <--- command = 0x80
ACPI: EC: ~~~> interrupt
ACPI: EC: ---> status = 0x08
ACPI: EC: <--- data = 0xa4
...
ACPI: Interpreter enabled
ACPI: (supports S0 S3 S4 S5)
ACPI: Using IOAPIC for interrupt routing
ACPI: EC: ---> status = 0x00
ACPI: EC: transaction start
ACPI: EC: <--- command = 0x80
Signed-off-by: NThomas Renninger <trenn@suse.de>
Acked-by: jbaron@redhat.com
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
CC: linux-acpi@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      6a5c083d
    • T
      Dynamic Debug: Introduce ddebug_query= boot parameter · a648ec05
      由 Thomas Renninger 提交于 
      Dynamic debug lacks the ability to enable debug messages at boot time.
One could patch initramfs or service startup scripts to write to
/sys/../dynamic_debug/control, but this sucks.

This patch makes it possible to pass a query in the same format one can
write to /sys/../dynamic_debug/control via boot param.
When dynamic debug gets initialized, this query will automatically be
applied.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Acked-by: jbaron@redhat.com
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      a648ec05
    • T
      Dynamic Debug: Split out query string parsing/setup from proc_write · fd89cfb8
      由 Thomas Renninger 提交于 
      The parsing and applying of dynamic debug strings is not only useful for
/sys/../dynamic_debug/control write access, but can also be used for
boot parameter parsing.
The boot parameter is introduced in a follow up patch.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Acked-by: jbaron@redhat.com
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      fd89cfb8
  9. 21 10月, 2010 1 次提交
    • A
      BKL: introduce CONFIG_BKL. · 6de5bd12
      由 Arnd Bergmann 提交于 
      With all the patches we have queued in the BKL removal tree, only a
few dozen modules are left that actually rely on the BKL, and even
there are lots of low-hanging fruit. We need to decide what to do
about them, this patch illustrates one of the options:

Every user of the BKL is marked as 'depends on BKL' in Kconfig,
and the CONFIG_BKL becomes a user-visible option. If it gets
disabled, no BKL using module can be built any more and the BKL
code itself is compiled out.

The one exception is file locking, which is practically always
enabled and does a 'select BKL' instead. This effectively forces
CONFIG_BKL to be enabled until we have solved the fs/lockd
mess and can apply the patch that removes the BKL from fs/locks.c.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      6de5bd12
  11. 19 10月, 2010 1 次提交
  13. 15 10月, 2010 2 次提交
    • A
      llseek: automatically add .llseek fop · 6038f373
      由 Arnd Bergmann 提交于 
      All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
      6038f373
    • C
      kmemleak: add TILE to the list of supported architectures. · 6b945df7
      由 Chris Metcalf 提交于 
      All the necessary functionality was already there; we just need
to make it possible to select the config option.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
      6b945df7
  15. 12 10月, 2010 2 次提交
  17. 08 10月, 2010 1 次提交
    • D
      move async raid6 test to lib/Kconfig.debug · 400fb7f6
      由 Dan Williams 提交于 
      The prompt for "Self test for hardware accelerated raid6 recovery" does not
belong in the top level configuration menu.  All the options in
crypto/async_tx/Kconfig are selected and do not depend on CRYPTO.
Kconfig.debug seems like a reasonable fit.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      400fb7f6
  19. 06 10月, 2010 2 次提交
    • C
      slub: Enable sysfs support for !CONFIG_SLUB_DEBUG · ab4d5ed5
      由 Christoph Lameter 提交于 
      Currently disabling CONFIG_SLUB_DEBUG also disabled SYSFS support meaning
that the slabs cannot be tuned without DEBUG.

Make SYSFS support independent of CONFIG_SLUB_DEBUG
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NPekka Enberg <penberg@kernel.org>
      ab4d5ed5
    • L
      modules: Fix module_bug_list list corruption race · 5336377d
      由 Linus Torvalds 提交于 
      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: NThomas 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: NLinus Torvalds <torvalds@linux-foundation.org>
      5336377d
  21. 02 10月, 2010 1 次提交
  23. 24 9月, 2010 1 次提交
  25. 23 9月, 2010 1 次提交
  27. 01 9月, 2010 1 次提交
    • S
      tracing/lockdep: Fix dependency of TRACE_IRQFLAGS · 46b93b74
      由 Steven Rostedt 提交于 
      When CONFIG_IRQSOFF_TRACER is set and CONFIG_PROVE_LOCKING is not, we
get the following error:

$  make oldconfig
scripts/kconfig/conf --oldconfig arch/x86/Kconfig
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)

This is because IRQSOFF_TRACER selects TRACE_IRQFLAGS but TRACE_IRQFLAGS
has PROVE_LOCKING as a dependency. This code is incorrect, and
this patch changes the TRACE_IRQFLAGS to be just a simple bool that
does not depend or select anything. Instead both IRQSOFF_TRACER and
PROVE_LOCKING select it.
Reported-by: NRichard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      46b93b74
  29. 31 8月, 2010 3 次提交
  31. 30 8月, 2010 1 次提交
  33. 24 8月, 2010 1 次提交