kprobes: bugfix: try_module_get even if calling_mod is NULL
When someone called register_*probe() from kernel-core code(not from
module) and that probes a kernel module, users can remove the probed
module because kprobe doesn't increment reference counter of the module.
(on the other hand, if the kernel-module calls register_*probe, kprobe
increments refcount of the probed module.)
Currently, we have no register_*probe() calling from kernel-core(except
smoke-test, but the smoke-test doesn't probe module), so there is no real
bugs. But the logic is wrong(or not fair) and it can causes a problem
when someone might want to probe module from kernel.
After this patch is applied, even if someone put register_*probe() call in
the kernel-core code, it increments the reference counter of the probed
module, and it prevents user to remove the module until stopping probing
it.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This solves several issues:
* It fixes the wrong idle clock polarity issue in a cleaner and less
expensive way.
* It handles the AT32AP7000 errata "SPI Chip Select 0 BITS field
overrides other Chip Selects". Other chips, e.g. AT91SAM9261, have
similar issues.
Currently, the AT91RM9200 code path is left alone. But it might be
interesting to try the same technique on RM9200 using a different CSR
register.
[dbrownell@users.sourceforge.net: restore debug message for activation] Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, we have a flag called "new_1" which is basically equivalent
to cpu_is_at91rm9200(). The latter is also called directly a few places.
Clean up this mess by introducing a atmel_spi_v2() function for
determining the controller version, and move all version dependent code
over to use it. This allows us to remove the new_1 flag.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Brownell [Tue, 6 Jan 2009 22:41:41 +0000 (14:41 -0800)]
spi_gpio driver
Generalize the old at91rm9200 "bootstrap" bitbanging SPI master driver as
"spi_gpio", so it works with arbitrary GPIOs and can be configured through
platform_data. Such SPI masters support:
- any number of bus instances (bus_num is the platform_device.id)
- any number of chipselects (one GPIO per spi_device)
- all four SPI_MODE values, and SPI_CS_HIGH
- i/o word sizes from 1 to 32 bits;
- devices configured as with any other spi_master controller
When configured using platform_data, this provides relatively low clock
rates. On platforms that support inlined GPIO calls, significantly
improved transfer speeds are also possible with a semi-custom driver.
(It's still painful when accessing flash memory, but less so.)
Sanity checked by using this version to replace both native controllers on
a board with six different SPI slaves, relying on three different
SPI_MODE_* values and both SPI_CS_HIGH settings for correct operation.
[akpm@linux-foundation.org: cleanups] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Magnus Damm <damm@igel.co.jp> Tested-by: Magnus Damm <damm@igel.co.jp> Cc: Torgil Svensson <torgil.svensson@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Tue, 6 Jan 2009 22:41:40 +0000 (14:41 -0800)]
dmi: fix kernel-doc notation
Add missing kernel-doc notation:
drivers/firmware/dmi_scan.c:475: No description found for parameter 'str'
drivers/firmware/dmi_scan.c:592: No description found for parameter 'f'
drivers/firmware/dmi_scan.c:592: No description found for parameter 'str'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicolas Palix [Tue, 6 Jan 2009 22:41:35 +0000 (14:41 -0800)]
drivers/macintosh: Add missing of_node_put in therm_adt746x.c
of_node_put is needed before discarding a value received from
of_find_node_by_name, eg in error handling code or when the device node is
no longer used.
The semantic match that catches the bug is as follows:
(http://www.emn.fr/x-info/coccinelle/)
n@p1 = of_find_node_by_name(...)
...
if (!n) S
... when != of_node_put(n)
when != n1 = f(n,...)
when != E = n
when any
when strict
(
return \(0\|<+...n...+>\|ptr\);
|
return@p2 ...;
|
of_node_put(n);
|
n1 = f(n,...)
|
E = n
)
Signed-off-by: Nicolas Palix <npalix@diku.dk> Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Darrick J. Wong [Tue, 6 Jan 2009 22:41:34 +0000 (14:41 -0800)]
adt7470: make automatic fan control really work
It turns out that the adt7470's automatic fan control algorithm only works
when the temperature sensors get updated. This in turn happens only when
someone tells the chip to read its temperature sensors. Regrettably, this
means that we have to drive the chip periodically.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Darrick J. Wong [Tue, 6 Jan 2009 22:41:33 +0000 (14:41 -0800)]
adt7470: observe the number of temperature sensors to shorten update time
The adt7470 driver currently assumes that 1s is the proper time to wait to
read all temperature sensors. However, the correct time is 200ms *
number_of_sensors. This patch sets the default time to provide for 10
sensors and then lowers it based on the number of sensor inputs that have
nozero values.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Darrick J. Wong [Tue, 6 Jan 2009 22:41:32 +0000 (14:41 -0800)]
adt7470: fix pwm at a certain level during temperature sensor scan
In the small window that it takes to read the temperature sensors, the pwm
outputs momentarily drop to 0. This causes a noticeable hiccup in fan
speed, which is slightly annoying. The solution is to manually program
the pwm output with whatever the automatic value is and then shift the
fans to manual control while reading temperatures. Once that is done, put
the fans back to whatever mode of control was there before.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Darrick J. Wong [Tue, 6 Jan 2009 22:41:31 +0000 (14:41 -0800)]
adt74{62, 70, 73}: Use DIV_ROUND_CLOSEST for rounded division
Modify some hwmon drivers to use DIV_ROUND_CLOSEST instead of bloating
source with (naughty) macros.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:29 +0000 (14:41 -0800)]
checkpatch: ensure we actually detect if assignments split across lines
When checking for assignments within if conditionals we check the whole of
the condition, but the match is performed using a line constrained regular
expression. This means we can miss split conditionals or those on the
second line. Allow the check to span lines.
Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:28 +0000 (14:41 -0800)]
checkpatch: do not report nr_static as a static declaration
Ensure we do not report identifiers containing the word static as static
declarations. For example this should not be reported as an unecessary
assignement of 0:
long nr_static = 0;
Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:27 +0000 (14:41 -0800)]
checkpatch: track #ifdef/#else/#endif when tracking blocks
When picking up a complete statement or block for analysis we cannot
simply track open/close/etc parenthesis we must take into account
preprocessor section boundaries.
Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:27 +0000 (14:41 -0800)]
checkpatch: fix continuation detection when handling spacing on operators
We are miscategorising a continuation fragment following an operator
which may lead to us thinking that there is a space after it when there is
not. Fix this up.
Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Frysinger [Tue, 6 Jan 2009 22:41:25 +0000 (14:41 -0800)]
checkpatch: try to catch missing VMLINUX_SYMBOL() in vmlinux.lds.h
Seems like every other release we have someone who updates vmlinux.lds.h
and adds C-visible symbols without VMLINUX_SYMBOL() around them. So start
checking the file and reject assignments which have plain symbols on
either side.
[apw@canonical.com: soften the check, add tests] Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:24 +0000 (14:41 -0800)]
checkpatch: allow parentheses on return for comparisons
It seems to be a common idiom to include braces on conditionals in all
contexts including return. Allow this exception to the return is not a
function checks. Reported by Kay Sievers.
Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Wolfram Sang [Tue, 6 Jan 2009 22:41:24 +0000 (14:41 -0800)]
checkpatch: Add warning for p0-patches
Some people work internally with -p0-patches which has the danger that one
forgets to convert them to -p1 before mainlining. Bitten myself and seen
p0-patches in mailing lists occasionally, this patch adds a warning to
checkpatch.pl in case a patch is -p0. If you really want, you can fool
this check to generate false positives, this is why it just spits a
warning. Making the check 100% proof is trickier than it looks, so let's
start with a version which catches the cases of real use.
[apw@canonical.com: update message language, handle null prefix, add tests] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:22 +0000 (14:41 -0800)]
checkpatch: update MAINTAINERS entry
Update my email address to my new work address. Also, as per our recent
email conversation remove Randy and Joel from the maintainers list.
Finally add LKML so that emails are recorded somewhere.
Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Joel Schopp <jschopp@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:20 +0000 (14:41 -0800)]
checkpatch: comment ends inside strings is most likely not an open comment
When we are detecting whether a comment is open when we start a hunk we
check for the first comment edge in the hunk and assume its inverse.
However if the hunk contains something like below, then we will assume
that a comment was open. Update this heuristic to see if the comment edge
is obviously within double quotes and ignore it if so:
foo(" */);
Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:17 +0000 (14:41 -0800)]
checkpatch: widen implied comment detection to allow multiple stars
Some people use double star '**' as a comment continuation, and start
comments with complete lines of stars. Widen the implied comment
detection to pick these up.
Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:16 +0000 (14:41 -0800)]
checkpatch: comment detection may miss an implied comment on the last hunk
When detecting implied comments from leading stars we may incorrectly
think we have detected an edge one way or the other when we have not if we
drop off the end of the last hunk. Fix this up.
Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Whitcroft [Tue, 6 Jan 2009 22:41:16 +0000 (14:41 -0800)]
checkpatch: add checks for in_atomic()
in_atomic() is not for driver use so report any such use as an ERROR.
Also in_atomic() is often used to determine if we may sleep, but it is not
reliable in this use model therefore strongly discourage its use.
Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Tue, 6 Jan 2009 22:41:15 +0000 (14:41 -0800)]
fs: fix function param name in kernel-doc
Fix function parameter name in kernel-doc:
Warning(linux-2.6.28-git5//fs/block_dev.c:1272): No description found for parameter 'pathname'
Warning(linux-2.6.28-git5//fs/block_dev.c:1272): Excess function parameter 'path' description in 'lookup_bdev'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Tue, 6 Jan 2009 22:41:13 +0000 (14:41 -0800)]
sysrq: more explicit, less terse help messages
Eliminate sysrq terse help mode; make sysrq help messages more meaningful
(more explicit/verbose). Make the sysrq action letter clearer by listing
it explicitly in more sysrq help messages (when it is not simple/clear).
Randy Dunlap [Tue, 6 Jan 2009 22:41:13 +0000 (14:41 -0800)]
fs/inode: fix kernel-doc notation
Fix kernel-doc notation:
Warning(linux-2.6.28-git3//fs/inode.c:120): No description found for parameter 'sb'
Warning(linux-2.6.28-git3//fs/inode.c:120): No description found for parameter 'inode'
Warning(linux-2.6.28-git3//fs/inode.c:588): No description found for parameter 'sb'
Warning(linux-2.6.28-git3//fs/inode.c:588): No description found for parameter 'inode'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.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>
commit 8308c54d7e312f7a03e2ce2057d0837e6fe3843f ("generic: redefine
resource_size_t as phys_addr_t") made CONFIG_RESOURCES_64BIT obsolete, but
didn't remove it. Remove it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Russell King [Tue, 6 Jan 2009 22:41:07 +0000 (14:41 -0800)]
remove linux/hardirq.h from asm-generic/local.h
While looking at reducing the amount of architecture namespace pollution
in the generic kernel, I found that asm/irq.h is included in the vast
majority of compilations on ARM (around 650 files.)
Since asm/irq.h includes a sub-architecture include file on ARM, this
causes a negative impact on the ccache's ability to re-use the build
results from other sub-architectures, so we have a desire to reduce the
dependencies on asm/irq.h.
It turns out that a major cause of this is the needless include of
linux/hardirq.h into asm-generic/local.h. The patch below removes this
include, resulting in some 250 to 300 files (around half) of the kernel
then omitting asm/irq.h.
My test builds still succeed, provided two ARM files are fixed
(arch/arm/kernel/traps.c and arch/arm/mm/fault.c) - so there may be
negative impacts for this on other architectures.
Note that x86 does not include asm/irq.h nor linux/hardirq.h in its
asm/local.h, so this patch can be viewed as bringing the generic version
into line with the x86 version.
[kosaki.motohiro@jp.fujitsu.com: add #include <linux/irqflags.h> to acpi/processor_idle.c]
[adobriyan@gmail.com: fix sparc64] Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Modify ioc4 to always load the sgiioc4 IDE module if the board carrying
the IOC4 hardware actually implements the IDE interface (not all boards
bring this functionality off the IOC4 chip). A drive hosted on the IDE
interface may contain the root filesystem, and sgiioc4 doesn't load
automatically as ioc4 owns the PCI device ID, not sgiioc4.
Eric Dumazet [Tue, 6 Jan 2009 22:41:04 +0000 (14:41 -0800)]
percpu_counter: FBC_BATCH should be a variable
For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS
Considering more and more distros are using high NR_CPUS values, it makes
sense to use a more sensible value for FBC_BATCH, and get rid of NR_CPUS.
A sensible value is 2*num_online_cpus(), with a minimum value of 32 (This
minimum value helps branch prediction in __percpu_counter_add())
We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically.
We rename FBC_BATCH to percpu_counter_batch since its not a constant
anymore.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Paul Mackerras [Tue, 6 Jan 2009 22:41:02 +0000 (14:41 -0800)]
Allow times and time system calls to return small negative values
At the moment, the times() system call will appear to fail for a period
shortly after boot, while the value it want to return is between -4095 and
-1. The same thing will also happen for the time() system call on 32-bit
platforms some time in 2106 or so.
On some platforms, such as x86, this is unavoidable because of the system
call ABI, but other platforms such as powerpc have a separate error
indication from the return value, so system calls can in fact return small
negative values without indicating an error. On those platforms,
force_successful_syscall_return() provides a way to indicate that the
system call return value should not be treated as an error even if it is
in the range which would normally be taken as a negative error number.
This adds a force_successful_syscall_return() call to the time() and
times() system calls plus their 32-bit compat versions, so that they don't
erroneously indicate an error on those platforms whose system call ABI has
a separate error indication. This will not affect anything on other
platforms.
Joakim Tjernlund added the fix for time() and the compat versions of
time() and times(), after I did the fix for times().
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Brownell [Tue, 6 Jan 2009 22:41:01 +0000 (14:41 -0800)]
documentation: when to BUG(), and when to not BUG()
Provide some basic advice about when to use BUG()/BUG_ON(): never, unless
there's really no better option.
This matches my understanding of the standard policy ... which seems not
to be written down so far, outside of LKML messages that I haven't
bookmarked.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tejun Heo [Tue, 6 Jan 2009 22:40:59 +0000 (14:40 -0800)]
poll: allow f_op->poll to sleep
f_op->poll is the only vfs operation which is not allowed to sleep. It's
because poll and select implementation used task state to synchronize
against wake ups, which doesn't have to be the case anymore as wait/wake
interface can now use custom wake up functions. The non-sleep restriction
can be a bit tricky because ->poll is not called from an atomic context
and the result of accidentally sleeping in ->poll only shows up as
temporary busy looping when the timing is right or rather wrong.
This patch converts poll/select to use custom wake up function and use
separate triggered variable to synchronize against wake up events. The
only added overhead is an extra function call during wake up and
negligible.
This patch removes the one non-sleep exception from vfs locking rules and
is beneficial to userland filesystem implementations like FUSE, 9p or
peculiar fs like spufs as it's very difficult for those to implement
non-sleeping poll method.
While at it, make the following cosmetic changes to make poll.h and
select.c checkpatch friendly.
* s/type * symbol/type *symbol/ : three places in poll.h
* remove blank line before EXPORT_SYMBOL() : two places in select.c
Oleg: spotted missing barrier in poll_schedule_timeout()
Davide: spotted missing write barrier in pollwake()
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Ingo Molnar <mingo@elte.hu> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Brad Boyer <flar@allandria.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Roland McGrath <roland@redhat.com> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scripts: script from kerneloops.org to pretty print oops dumps
We're struggling all the time to figure out where the code came from that
oopsed.. The script below (a adaption from a script used by
kerneloops.org) can help developers quite a bit, at least for non-module
cases.
memory = agp_allocate_memory(agp_bridge, pg_count, type); c055c10f: 89 c2 mov %eax,%edx
if (memory == NULL) c055c111: 74 19 je c055c12c <agp_allocate_memory_wrap+0x30>
/* This function must only be called when current_controller != NULL */
static void agp_insert_into_pool(struct agp_memory * temp)
{
struct agp_memory *prev;
so in this case, we faulted while dereferencing agp_fe.current_controller
pointer, and we get to see exactly which function and line it affects...
Personally I find this very useful, and I can see value for having this
script in the kernel for more-than-just-me to use.
Caveats:
* It only works for oopses not-in-modules
* It only works nicely for kernels compiled with CONFIG_DEBUG_INFO
* It's not very fast.
* It only works on x86
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... because we do want repeated same-oops to be seen by automated
tools like kerneloops.org
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Machek [Tue, 6 Jan 2009 22:40:53 +0000 (14:40 -0800)]
strict_strto* is not strict enough
It decodes "\n" as 0, which is bad, because stray echo into backlight
will turn your backlight off, etc...
Signed-off-by: Pavel Machek <pavel@suse.cz> Cc: Yi Yang <yi.y.yang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Frysinger [Tue, 6 Jan 2009 22:40:53 +0000 (14:40 -0800)]
autodetect_raid: add missing __init marking
The function autodetect_raid is only used by __init functions, and it refers
to __initdata, so it needs __init markings. Fixes this error:
The function autodetect_raid() references
the variable __initdata raid_noautodetect.
This is often because autodetect_raid lacks a __initdata
annotation or the annotation of raid_noautodetect is wrong.
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Qinghuang Feng [Tue, 6 Jan 2009 22:40:52 +0000 (14:40 -0800)]
samples: mark {static|__init|__exit} for {init|exit} functions
None of these (init|exit) functions is called from other functions which
is outside the kernel module mechanism or kernel itself, so mark them as
{static|__init|__exit}.
Darrick J. Wong [Tue, 6 Jan 2009 22:40:51 +0000 (14:40 -0800)]
Create a DIV_ROUND_CLOSEST macro to do division with rounding
Create a helper macro to divide two numbers and round the result to the
nearest whole number. This is a helper macro for hwmon drivers that want
to convert incoming sysfs values per standard hwmon practice, though the
macro itself can be used by anyone.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/exec.c:__bprm_mm_init(): clean up error handling
Untangle the error unwinding in this function, saving a test of local
variable `vma'.
Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Marton Balint [Tue, 6 Jan 2009 22:40:43 +0000 (14:40 -0800)]
do_mounts: add device info to mount message
In the past, I used the root=... command line parameter to specify the
root filesystem to the kernel. Now it seems that specifying it is not
necessary. The kernel detects the root filesystem even if the kernel
command line is empty. My root fs is on a raid1 device by the way, and I
am not using initrd for the boot process.
If the kernel detects the root filesystem somehow, I think it should print
out the result of this detection, otherwise I will not know which device
has the root filesystem. Or is there an easy way to get this information
on a running system? I had a quick look at the /proc and /sys
filesystems, but haven't found anything useful there.
Signed-off-by: Marton Balint <cus@fazekas.hu> Cc: Christoph Hellwig <hch@lst.de> 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>
oops handling: ensure that any oops is flushed to the mtdoops console
This used to work unpatched with older kernels, during the development
phase of mtdoops. Before commit e3e8a75d2acfc61ebf25524666a0a2c6abb0620c
a space was printed with console_loglevel set to 15, which probably
flushed the oops message as a side effect.
This is another patch from the Nokia N810 kernel.
Signed-off-by: Viktor Rosendahl <viktor.rosendahl@nokia.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several subsystem open handlers dereference the fops_get() return value
without checking it for nullness. This opens a race condition between the
open handler and module unloading.
A module can be marked as being unloaded (MODULE_STATE_GOING) before its
exit function is called and gets the chance to unregister the driver.
During that window open handlers can still be called, and fops_get() will
fail in try_module_get() and return a NULL pointer.
This change checks the fops_get() return value and returns -ENODEV if NULL.
Reported-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk> Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be> Acked-by: Takashi Iwai <tiwai@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Airlie <airlied@linux.ie> Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the newly introduced pci_ioremap_bar() function in drivers/misc.
pci_ioremap_bar() just takes a pci device and a bar number, with the goal
of making it really hard to get wrong, while also having a central place
to stick sanity checks.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Tue, 6 Jan 2009 22:40:39 +0000 (14:40 -0800)]
atomic_t: unify all arch definitions
The atomic_t type cannot currently be used in some header files because it
would create an include loop with asm/atomic.h. Move the type definition
to linux/types.h to break the loop.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rakib Mullick [Tue, 6 Jan 2009 22:40:38 +0000 (14:40 -0800)]
init: properly placing noinline keyword
checkpatch warns about 'static void noinline'. It wants `static noinline
void'.
Both are permissible, but the kernel consistently uses `static inline' and
`static noinline', and consistency is good. Hence let's keep the
checkpatch warning and fix up this code site.
[akpm@linux-foundation.org: rewrote changelog] Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KOSAKI Motohiro [Tue, 6 Jan 2009 22:40:33 +0000 (14:40 -0800)]
mm: stop kswapd's infinite loop at high order allocation
Wassim Dagash reported following kswapd infinite loop problem.
kswapd runs in some infinite loop trying to swap until order 10 of zone
highmem is OK.... kswapd will continue to try to balance order 10 of zone
highmem forever (or until someone release a very large chunk of highmem).
For non order-0 allocations, the system may never be balanced due to
fragmentation but kswapd should not infinitely loop as a result.
Instead, recheck all watermarks at order-0 as they are the most important.
If watermarks are ok, kswapd will go back to sleep.
Johannes Weiner [Tue, 6 Jan 2009 22:40:32 +0000 (14:40 -0800)]
bootmem: print request details before BUG_ON(them)
Moving the request details print-out before the sanity checks that
might panic() enables us to analyse invalid requests without having
access to the line information of the stack dump.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses
mm->hiwater_xxx directly, this leads to 2 problems:
- taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any
moment before the task exits, so we should check the current values of
rss/vm anyway.
- do_exit()->update_hiwater_xxx() calls are racy. An exiting thread can
be preempted right before mm->hiwater_xxx = new_val, and another thread
can use A_LOT of memory and exit in between. When the first thread
resumes it can be the last thread in the thread group, in that case we
report the wrong hiwater_xxx values which do not take A_LOT into
account.
Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change
xacct_add_tsk() to use them. The first helper will also be used by
rusage->ru_maxrss accounting.
Kill do_exit()->update_hiwater_xxx() calls. Unless we are going to
decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody
can look at this mm_struct when exit_mmap() actually unmaps the memory.
Nick Piggin [Tue, 6 Jan 2009 22:40:28 +0000 (14:40 -0800)]
mm: pagecache gfp flags fix
Frustratingly, gfp_t is really divided into two classes of flags. One are
the context dependent ones (can we sleep? can we enter filesystem? block
subsystem? should we use some extra reserves, etc.). The other ones are
the type of memory required and depend on how the algorithm is implemented
rather than the point at which the memory is allocated (highmem? dma
memory? etc).
Some of the functions which allocate a page and add it to page cache take
a gfp_t, but sometimes those functions or their callers aren't really
doing the right thing: when allocating pagecache page, the memory type
should be mapping_gfp_mask(mapping). When allocating radix tree nodes,
the memory type should be kernel mapped (not highmem) memory. The gfp_t
argument should only really be needed for context dependent options.
This patch doesn't really solve that tangle in a nice way, but it does
attempt to fix a couple of bugs.
- find_or_create_page changes its radix-tree allocation to only include
the main context dependent flags in order so the pagecache page may be
allocated from arbitrary types of memory without affecting the
radix-tree. In practice, slab allocations don't come from highmem
anyway, and radix-tree only uses slab allocations. So there isn't a
practical change (unless some fs uses GFP_DMA for pages).
- grab_cache_page_nowait() is changed to allocate radix-tree nodes with
GFP_NOFS, because it is not supposed to reenter the filesystem. This
bug could cause lock recursion if a filesystem is not expecting the
function to reenter the fs (as-per documentation).
Filesystems should be careful about exactly what semantics they want and
what they get when fiddling with gfp_t masks to allocate pagecache. One
should be as liberal as possible with the type of memory that can be used,
and same for the the context specific flags.
Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:40:26 +0000 (14:40 -0800)]
fs: sys_sync fix
s_syncing livelock avoidance was breaking data integrity guarantee of
sys_sync, by allowing sys_sync to skip writing or waiting for superblocks
if there is a concurrent sys_sync happening.
This livelock avoidance is much less important now that we don't have the
get_super_to_sync() call after every sb that we sync. This was replaced
by __put_super_and_need_restart.
Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:40:25 +0000 (14:40 -0800)]
fs: sync_sb_inodes fix
Fix data integrity semantics required by sys_sync, by iterating over all
inodes and waiting for any writeback pages after the initial writeout.
Comments explain the exact problem.
Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:40:25 +0000 (14:40 -0800)]
fs: remove WB_SYNC_HOLD
Remove WB_SYNC_HOLD. The primary motiviation is the design of my
anti-starvation code for fsync. It requires taking an inode lock over the
sync operation, so we could run into lock ordering problems with multiple
inodes. It is possible to take a single global lock to solve the ordering
problem, but then that would prevent a future nice implementation of "sync
multiple inodes" based on lock order via inode address.
Seems like a backward step to remove this, but actually it is busted
anyway: we can't use the inode lists for data integrity wait: an inode can
be taken off the dirty lists but still be under writeback. In order to
satisfy data integrity semantics, we should wait for it to finish
writeback, but if we only search the dirty lists, we'll miss it.
It would be possible to have a "writeback" list, for sys_sync, I suppose.
But why complicate things by prematurely optimise? For unmounting, we
could avoid the "livelock avoidance" code, which would be easier, but
again premature IMO.
Fixing the existing data integrity problem will come next.
Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
WB_SYNC_HOLD is going to be zapped so we should not use it. Use
%WB_SYNC_NONE instead. Here is what akpm said:
"I think I'll just switch that to WB_SYNC_NONE. The `wait==0' mode is
just an advisory thing to help the fs shove lots of data into the
queues. If some gets missed then it'll be picked up on the second
->sync_fs call, with wait==1."
Thanks to Randy Dunlap for catching this.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:40:22 +0000 (14:40 -0800)]
mm: direct IO starvation improvement
Direct IO can invalidate and sync a lot of pagecache pages in the mapping.
A 4K direct IO will actually try to sync and/or invalidate the pagecache
of the entire file, for example (which might be many GB or TB large).
Improve this by doing range syncs. Also, memory no longer has to be
unmapped to catch the dirty bits for syncing, as dirty bits would remain
coherent due to dirty mmap accounting.
This fixes the immediate DM deadlocks when doing direct IO reads to block
device with a mounted filesystem, if only by papering over the problem
somewhat rather than addressing the fsync starvation cases.
Signed-off-by: Nick Piggin <npiggin@suse.de> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matt Mackall [Tue, 6 Jan 2009 22:40:20 +0000 (14:40 -0800)]
shmem: unify regular and tiny shmem
tiny-shmem shares most of its 130 lines of code with shmem and tends to
break when particular bits of shmem get modified. Unifying saves code and
makes keeping these two in sync much easier.
Ying Han [Tue, 6 Jan 2009 22:40:18 +0000 (14:40 -0800)]
mm: make get_user_pages() interruptible
The initial implementation of checking TIF_MEMDIE covers the cases of OOM
killing. If the process has been OOM killed, the TIF_MEMDIE is set and it
return immediately. This patch includes:
1. add the case that the SIGKILL is sent by user processes. The
process can try to get_user_pages() unlimited memory even if a user
process has sent a SIGKILL to it(maybe a monitor find the process
exceed its memory limit and try to kill it). In the old
implementation, the SIGKILL won't be handled until the get_user_pages()
returns.
2. change the return value to be ERESTARTSYS. It makes no sense to
return ENOMEM if the get_user_pages returned by getting a SIGKILL
signal. Considering the general convention for a system call
interrupted by a signal is ERESTARTNOSYS, so the current return value
is consistant to that.
Lee:
An unfortunate side effect of "make-get_user_pages-interruptible" is that
it prevents a SIGKILL'd task from munlock-ing pages that it had mlocked,
resulting in freeing of mlocked pages. Freeing of mlocked pages, in
itself, is not so bad. We just count them now--altho' I had hoped to
remove this stat and add PG_MLOCKED to the free pages flags check.
However, consider pages in shared libraries mapped by more than one task
that a task mlocked--e.g., via mlockall(). If the task that mlocked the
pages exits via SIGKILL, these pages would be left mlocked and
unevictable.
Proposed fix:
Add another GUP flag to ignore sigkill when calling get_user_pages from
munlock()--similar to Kosaki Motohiro's 'IGNORE_VMA_PERMISSIONS flag for
the same purpose. We are not actually allocating memory in this case,
which "make-get_user_pages-interruptible" intends to avoid. We're just
munlocking pages that are already resident and mapped, and we're reusing
get_user_pages() to access those pages.
?? Maybe we should combine 'IGNORE_VMA_PERMISSIONS and '_IGNORE_SIGKILL
into a single flag: GUP_FLAGS_MUNLOCK ???
[Lee.Schermerhorn@hp.com: ignore sigkill in get_user_pages during munlock] Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Hugh Dickins <hugh@veritas.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Rohit Seth <rohitseth@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:13 +0000 (14:40 -0800)]
badpage: KERN_ALERT BUG instead of KERN_EMERG
bad_page() and rmap Eeek messages have said KERN_EMERG for a few years,
which I've followed in print_bad_pte(). These are serious system errors,
on a par with BUGs, but they're not quite emergencies, and we do our best
to carry on: say KERN_ALERT "BUG: " like the x86 oops does.
And remove the "Trying to fix it up, but a reboot is needed" line: it's
not untrue, but I hope the KERN_ALERT "BUG: " conveys as much.
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:12 +0000 (14:40 -0800)]
badpage: ratelimit print_bad_pte and bad_page
print_bad_pte() and bad_page() might each need ratelimiting - especially
for their dump_stacks, almost never of interest, yet not quite
dispensible. Correlating corruption across neighbouring entries can be
very helpful, so allow a burst of 60 reports before keeping quiet for the
remainder of that minute (or allow a steady drip of one report per
second).
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:11 +0000 (14:40 -0800)]
badpage: remove vma from page_remove_rmap
Remove page_remove_rmap()'s vma arg, which was only for the Eeek message.
And remove the BUG_ON(page_mapcount(page) == 0) from CONFIG_DEBUG_VM's
page_dup_rmap(): we're trying to be more resilient about that than BUGs.
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:10 +0000 (14:40 -0800)]
badpage: zap print_bad_pte on swap and file
Complete zap_pte_range()'s coverage of bad pagetable entries by calling
print_bad_pte() on a pte_file in a linear vma and on a bad swap entry.
That needs free_swap_and_cache() to tell it, which will also have shown
one of those "swap_free" errors (but with much less information).
Similar checks in fork's copy_one_pte()? No, that would be more noisy
than helpful: we'll see them when parent and child exec or exit.
Where do_nonlinear_fault() calls print_bad_pte(): omit !VM_CAN_NONLINEAR
case, that could only be a bug in sys_remap_file_pages(), not a bad pte.
VM_FAULT_OOM rather than VM_FAULT_SIGBUS? Well, okay, that is consistent
with what happens if do_swap_page() operates a bad swap entry; but don't
we have patches to be more careful about killing when VM_FAULT_OOM?
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:09 +0000 (14:40 -0800)]
badpage: vm_normal_page use print_bad_pte
print_bad_pte() is so far being called only when zap_pte_range() finds
negative page_mapcount, or there's a fault on a pte_file where it does not
belong. That's weak coverage when we suspect pagetable corruption.
Originally, it was called when vm_normal_page() found an invalid pfn: but
pfn_valid is expensive on some architectures and configurations, so 2.6.24
put that under CONFIG_DEBUG_VM (which doesn't help in the field), then
2.6.26 replaced it by a VM_BUG_ON (likewise).
Reinstate the print_bad_pte() in vm_normal_page(), but use a cheaper test
than pfn_valid(): memmap_init_zone() (used in bootup and hotplug) keep a
__read_mostly note of the highest_memmap_pfn, vm_normal_page() then check
pfn against that. We could call this pfn_plausible() or pfn_sane(), but I
doubt we'll need it elsewhere: of course it's not reliable, but gives much
stronger pagetable validation on many boxes.
Also use print_bad_pte() when the pte_special bit is found outside a
VM_PFNMAP or VM_MIXEDMAP area, instead of VM_BUG_ON.
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:40:08 +0000 (14:40 -0800)]
badpage: replace page_remove_rmap Eeek and BUG
Now that bad pages are kept out of circulation, there is no need for the
infamous page_remove_rmap() BUG() - once that page is freed, its negative
mapcount will issue a "Bad page state" message and the page won't be
freed. Removing the BUG() allows more info, on subsequent pages, to be
gathered.
We do have more info about the page at this point than bad_page() can know
- notably, what the pmd is, which might pinpoint something like low 64kB
corruption - but page_remove_rmap() isn't given the address to find that.
In practice, there is only one call to page_remove_rmap() which has ever
reported anything, that from zap_pte_range() (usually on exit, sometimes
on munmap). It has all the info, so remove page_remove_rmap()'s "Eeek"
message and leave it all to zap_pte_range().
mm/memory.c already has a hardly used print_bad_pte() function, showing
some of the appropriate info: extend it to show what we want for the rmap
case: pte info, page info (when there is a page) and vma info to compare.
zap_pte_range() already knows the pmd, but print_bad_pte() is easier to
use if it works that out for itself.
Some of this info is also shown in bad_page()'s "Bad page state" message.
Keep them separate, but adjust them to match each other as far as
possible. Say "Bad page map" in print_bad_pte(), and add a TAINT_BAD_PAGE
there too.
print_bad_pte() show current->comm unconditionally (though it should get
repeated in the usually irrelevant stack trace): sorry, I misled Nick
Piggin to make it conditional on vm_mm == current->mm, but current->mm is
already NULL in the exit case. Usually current->comm is good, though
exceptionally it may not be that of the mm (when "swapoff" for example).
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / linux-2.6-omap-h63xx.git / log