| Age | Commit message (Collapse) | Author | Files | Lines |
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Move the instrumentation Kconfig to
arch/Kconfig for architecture dependent options
- oprofile
- kprobes
and
init/Kconfig for architecture independent options
- profiling
- markers
Remove the "Instrumentation Support" menu. Everything moves to "General setup".
Delete the kernel/Kconfig.instrumentation file.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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Linus:
On the per-architecture side, I do think it would be better to *not* have
internal architecture knowledge in a generic file, and as such a line like
depends on X86_32 || IA64 || PPC || S390 || SPARC64 || X86_64 || AVR32
really shouldn't exist in a file like kernel/Kconfig.instrumentation.
It would be much better to do
depends on ARCH_SUPPORTS_KPROBES
in that generic file, and then architectures that do support it would just
have a
bool ARCH_SUPPORTS_KPROBES
default y
in *their* architecture files. That would seem to be much more logical,
and is readable both for arch maintainers *and* for people who have no
clue - and don't care - about which architecture is supposed to support
which interface...
Changelog:
Actually, I know I gave this as the magic incantation, but now that I see
it, I realize that I should have told you to just use
config KPROBES_SUPPORT
def_bool y
instead, which is a bit denser.
We seem to use both kinds of syntax for these things, but this is really
what "def_bool" is there for...
- Use HAVE_KPROBES
- Use a select
- Yet another update :
Moving to HAVE_* now.
- Update ARM for kprobes support.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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Linus:
On the per-architecture side, I do think it would be better to *not* have
internal architecture knowledge in a generic file, and as such a line like
depends on X86_32 || IA64 || PPC || S390 || SPARC64 || X86_64 || AVR32
really shouldn't exist in a file like kernel/Kconfig.instrumentation.
It would be much better to do
depends on ARCH_SUPPORTS_KPROBES
in that generic file, and then architectures that do support it would just
have a
bool ARCH_SUPPORTS_KPROBES
default y
in *their* architecture files. That would seem to be much more logical,
and is readable both for arch maintainers *and* for people who have no
clue - and don't care - about which architecture is supposed to support
which interface...
Changelog:
Actually, I know I gave this as the magic incantation, but now that I see
it, I realize that I should have told you to just use
config ARCH_SUPPORTS_KPROBES
def_bool y
instead, which is a bit denser.
We seem to use both kinds of syntax for these things, but this is really
what "def_bool" is there for...
Changelog :
- Moving to HAVE_*.
- Add AVR32 oprofile.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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The conflicting commit for
move-kconfiginstrumentation-to-arch-kconfig-and-init-kconfig.patch
is the ARM fix from Linus :
commit 38ad9aebe70dc72df08851bbd1620d89329129ba
He just seemed to agree that my approach (just putting the missing ARM
config options in arch/arm/Kconfig) works too. The main advantage it has
is that it is smaller, does not need a cleanup in the future and does
not break the following patches unnecessarily.
It's just been discussed here
http://lkml.org/lkml/2008/1/15/267
However, Linus might prefer to stay with his own patch and I would
totally understand it that late in the release cycle. Therefore I submit
this for the next release cycle.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: Russell King <rmk+lkml@arm.linux.org.uk>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6
* 'suspend' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (38 commits)
suspend: cleanup reference to swsusp_pg_dir[]
PM: Remove obsolete /sys/devices/.../power/state docs
Hibernation: Invoke suspend notifications after console switch
Suspend: Invoke suspend notifications after console switch
Suspend: Clean up suspend_64.c
Suspend: Add config option to disable the freezer if architecture wants that
ACPI: Print message before calling _PTS
ACPI hibernation: Call _PTS before suspending devices
Hibernation: Introduce begin() and end() callbacks
ACPI suspend: Call _PTS before suspending devices
ACPI: Separate disabling of GPEs from _PTS
ACPI: Separate invocations of _GTS and _BFS from _PTS and _WAK
Suspend: Introduce begin() and end() callbacks
suspend: fix ia64 allmodconfig build
ACPI: clear GPE earily in resume to avoid warning
Suspend: Clean up Kconfig (V2)
Hibernation: Clean up Kconfig (V2)
Hibernation: Update messages
Suspend: Use common prefix in messages
Hibernation: Remove unnecessary variable declaration
...
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Rafael J. Wysocki reported weird, multi-seconds delays during
suspend/resume and bisected it back to:
commit 82a1fcb90287052aabfa235e7ffc693ea003fe69
Author: Ingo Molnar <mingo@elte.hu>
Date: Fri Jan 25 21:08:02 2008 +0100
softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
fix it:
- restore the old wakeup mechanism
- fix break usage in do_each_thread() { } while_each_thread().
- fix the hotplug switch stmt, a fall-through case was broken.
Bisected-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Following the recent change in the suspend code path, switch consoles before
calling PM notifiers during hibernation.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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In order to fix APM emulation it is necessary to enable apm-emulation
notifications for suspends triggered in various ways via the suspend
notifiers. However, this will cause the systems using APM emulation
to lock up between X being needed to switch away from the VT and X
already waiting for resume in the APM ioctl.
This patch moves the console switch (if enabled) before the suspend
notification (and after the resume notification) to avoid this issue.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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This patch makes the freezer optional for suspend to allow the
system to work (or not work) like the original PMU suspend.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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Introduce global hibernation callback .end() and rename global
hibernation callback .start() to .begin(), in analogy with the
recent modifications of the global suspend callbacks.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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On ACPI systems the target state set by acpi_pm_set_target() is
reset by acpi_pm_finish(), but that need not be called if the
suspend fails. All platforms that use the .set_target() global
suspend callback are affected by analogous issues.
For this reason, we need an additional global suspend callback that
will reset the target state regardless of whether or not the suspend
is successful. Also, it is reasonable to rename the .set_target()
callback, since it will be used for a different purpose on ACPI
systems (due to ACPI 1.0x code ordering requirements).
Introduce the global suspend callback .end() to be executed at the
end of the suspend sequence and rename the .set_target() global
suspend callback to .begin().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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kernel/power/main.c:488: error: ‘pm_test_attr’ undeclared here (not in a function)
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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This cleans up the suspend Kconfig and removes the need to
declare centrally which architectures support suspend. All
architectures that currently support suspend are modified
accordingly.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Pavel Machek <pavel@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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This cleans up the hibernation Kconfig and removes the need to
declare centrally which architectures support hibernation. All
architectures that currently support hibernation are modified
accordingly.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Pavel Machek <pavel@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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Make hibernation messages start with one common prefix "PM: " and use
the word "hibernation" in the messages as a synonym of "suspend to
disk".
Turn some KERN_INFO messages into debug ones.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Make suspend messages start with one common prefix "PM: ".
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Remove the unnecessary extern declaration of resume_file[]
from kernel/power/swap.c .
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Fix a comment in kernel/power/disk.c so that it doesn't contain lines
longer that 80 characters.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Fix a comment in kernel/power/main.c so that it doesn't contain lines
longer that 80 characters.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Move the low level restore code to kernel/power/disk.c , since the
corresponding low level hibernation code is already there.
Make restore fail if device_power_down(PMSG_PRETHAW) returns an
error.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Suspend: Make debug facility depend on CONFIG_SUSPEND
Make the new suspend debug facility code depend on CONFIG_SUSPEND,
as appropriate, to remove the compiler warning printed when CONFIG_PM is set
and CONFIG_SUSPEND is not set.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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This patch (as1008b) converts the PM notifier routines from inline
calls to out-of-line code. It also prevents pm_chain_head from
being created when CONFIG_PM_SLEEP isn't enabled, and EXPORTs the
notifier registration and unregistration routines.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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When trying to debug a suspend failure I started implementing
PM_TRACE for powerpc. I then noticed that I'm debugging a suspend
failure and so PM_TRACE isn't useful at all, but thought that
nonetheless this could be useful in the future.
Basically, to support PM_TRACE, you add a Kconfig option that
selects PM_TRACE and provides the infrastructure as per the
help text of PM_TRACE.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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Make it possible to test the hibernation core code with the help of the
/sys/power/pm_test attribute introduced for suspend testing in the previous
patch.
Writing an appropriate string to this file causes the hibernation code to work
in one of the test modes defined as follows:
freezer
- test the freezing of processes
devices
- test the freezing of processes and suspending of devices
platform
- test the freezing of processes, suspending of devices and platform global
control methods(*)
processors
- test the freezing of processes, suspending of devices, platform global
control methods(*) and the disabling of nonboot CPUs
core
- test the freezing of processes, suspending of devices, platform global
control methods(*), the disabling of nonboot CPUs and suspending of
platform/system devices
(*) - the platform global control methods are only available on ACPI systems
and are only tested if the hibernation mode is set to "platform"
Then, if a hibernation is started by normal means, the hibernation core will
perform its normal operations up to the point indicated by given test level.
Next, it will wait for 5 seconds and carry out the resume operations needed to
transition the system back to the fully functional state.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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Introduce sysfs attribute /sys/power/pm_test allowing one to test the suspend
core code. Namely, writing one of the strings:
freezer
devices
platform
processors
core
to this file causes the suspend code to work in one of the test modes defined as
follows:
freezer
- test the freezing of processes
devices
- test the freezing of processes and suspending of devices
platform
- test the freezing of processes, suspending of devices and platform global
control methods(*)
processors
- test the freezing of processes, suspending of devices, platform global
control methods and the disabling of nonboot CPUs
core
- test the freezing of processes, suspending of devices, platform global
control methods, the disabling of nonboot CPUs and suspending of
platform/system devices
(*) These are ACPI global control methods on ACPI systems
Then, if a suspend is started by normal means, the suspend core will perform
its normal operations up to the point indicated by given test level. Next, it
will wait for 5 seconds and carry out the resume operations needed to transition
the system back to the fully functional state.
Writing "none" to /sys/power/pm_test turns the testing off.
When open for reading, /sys/power/pm_test contains a space-separated list of all
available tests (including "none" that represents the normal functionality) in
which the current test level is indicated by square brackets.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Add PM_RESTORE_PREPARE and PM_POST_RESTORE notifiers to the PM core, to be used
in analogy with the existing PM_HIBERNATION_PREPARE and PM_POST_HIBERNATION
notifiers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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This patch moves the prototypes of count_highmem_pages() and
restore_highmem() to kernel/power/power.h
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
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Move the definitions of hibernation ioctls to a separate header file in
include/linux, which can be exported to the user space.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Three ioctl numbers belonging to the hibernation userland interface,
SNAPSHOT_ATOMIC_SNAPSHOT, SNAPSHOT_AVAIL_SWAP, SNAPSHOT_GET_SWAP_PAGE,
are defined in a wrong way (eg. not portable). Provide new ioctl numbers for
these ioctls and mark the existing ones as deprecated.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Mark the SNAPSHOT_SET_SWAP_FILE ioctl belonging to the hibernation userland
interface as deprecated.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Modify the hibernation userland interface by adding two new ioctls to it,
SNAPSHOT_PLATFORM_SUPPORT and SNAPSHOT_POWER_OFF, that can be used,
respectively, to switch the hibernation platform support on/off and to make the
kernel transition the system to the hibernation state (eg. ACPI S4) using the
platform (eg. ACPI) driver.
These ioctls are intended to replace the misdesigned SNAPSHOT_PMOPS ioctl,
which from now is regarded as obsolete and will be removed in the future.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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Add a new ioctl, SNAPSHOT_GET_IMAGE_SIZE, returning the size of the (just
created) hibernation image, to the hibernation userland interface.
This ioctl is necessary so that the userland utilities using the interface need
not access the hibernation image header, owned by the kernel, in order to obtain
the size of the image.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b46' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
[AUDIT] Add uid, gid fields to ANOM_PROMISCUOUS message
[AUDIT] ratelimit printk messages audit
[patch 2/2] audit: complement va_copy with va_end()
[patch 1/2] kernel/audit.c: warning fix
[AUDIT] create context if auditing was ever enabled
[AUDIT] clean up audit_receive_msg()
[AUDIT] make audit=0 really stop audit messages
[AUDIT] break large execve argument logging into smaller messages
[AUDIT] include audit type in audit message when using printk
[AUDIT] do not panic on exclude messages in audit_log_pid_context()
[AUDIT] Add End of Event record
[AUDIT] add session id to audit messages
[AUDIT] collect uid, loginuid, and comm in OBJ_PID records
[AUDIT] return EINTR not ERESTART*
[PATCH] get rid of loginuid races
[PATCH] switch audit_get_loginuid() to task_struct *
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some printk messages from the audit system can become excessive. This
patch ratelimits those messages. It was found that messages, such as
the audit backlog lost printk message could flood the logs to the point
that a machine could take an nmi watchdog hit or otherwise become
unresponsive.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Complement va_copy() with va_end().
Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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kernel/audit.c: In function 'audit_log_start':
kernel/audit.c:1133: warning: 'serial' may be used uninitialized in this function
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Disabling audit at runtime by auditctl doesn't mean that we can
stop allocating contexts for new processes; we don't want to miss them
when that sucker is reenabled.
(based on work from Al Viro in the RHEL kernel series)
Signed-off-by: Eric Paris <eparis@redhat.com>
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generally clean up audit_receive_msg() don't free random memory if
selinux_sid_to_string fails for some reason. Move generic auditing
to a helper function
Signed-off-by: Eric Paris <eparis@redhat.com>
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Some audit messages (namely configuration changes) are still emitted even if
the audit subsystem has been explicitly disabled. This patch turns those
messages off as well.
Signed-off-by: Eric Paris <eparis@redhat.com>
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execve arguments can be quite large. There is no limit on the number of
arguments and a 4G limit on the size of an argument.
this patch prints those aruguments in bite sized pieces. a userspace size
limitation of 8k was discovered so this keeps messages around 7.5k
single arguments larger than 7.5k in length are split into multiple records
and can be identified as aX[Y]=
Signed-off-by: Eric Paris <eparis@redhat.com>
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Currently audit drops the audit type when an audit message goes through
printk instead of the audit deamon. This is a minor annoyance in
that the audit type is no longer part of the message and the information
the audit type conveys needs to be carried in, or derived from the
message data.
The attached patch includes the type number as part of the printk.
Admittedly it isn't the type name that the audit deamon provides but I
think this is better than dropping the type completely.
Signed-pff-by: John Johansen <jjohansen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
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If we fail to get an ab in audit_log_pid_context this may be due to an exclude
rule rather than a memory allocation failure. If it was due to a memory
allocation failue we would have already paniced and no need to do it again.
Signed-off-by: Eric Paris <eparis@redhat.com>
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This patch adds an end of event record type. It will be sent by the kernel as
the last record when a multi-record event is triggered. This will aid realtime
analysis programs since they will now reliably know they have the last record
to complete an event. The audit daemon filters this and will not write it to
disk.
Signed-off-by: Steve Grubb <sgrubb redhat com>
Signed-off-by: Eric Paris <eparis@redhat.com>
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In order to correlate audit records to an individual login add a session
id. This is incremented every time a user logs in and is included in
almost all messages which currently output the auid. The field is
labeled ses= or oses=
Signed-off-by: Eric Paris <eparis@redhat.com>
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Add uid, loginuid, and comm collection to OBJ_PID records. This just
gives users a little more information about the task that received a
signal. pid is rather meaningless after the fact, and even though comm
isn't great we can't collect exe reasonably on this code path for
performance reasons.
Signed-off-by: Eric Paris <eparis@redhat.com>
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The syscall exit code will change ERESTART* kernel internal return codes
to EINTR if it does not restart the syscall. Since we collect the audit
info before that point we should fix those in the audit log as well.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Keeping loginuid in audit_context is racy and results in messier
code. Taken to task_struct, out of the way of ->audit_context
changes.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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all callers pass something->audit_context
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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To allow the implementation of optimized rw-locks in user space, glibc
needs a possibility to select waiters for wakeup depending on a bitset
mask.
This requires two new futex OPs: FUTEX_WAIT_BITS and FUTEX_WAKE_BITS
These OPs are basically the same as FUTEX_WAIT and FUTEX_WAKE plus an
additional argument - a bitset. Further the FUTEX_WAIT_BITS OP is
expecting an absolute timeout value instead of the relative one, which
is used for the FUTEX_WAIT OP.
FUTEX_WAIT_BITS calls into the kernel with a bitset. The bitset is
stored in the futex_q structure, which is used to enqueue the waiter
into the hashed futex waitqueue.
FUTEX_WAKE_BITS also calls into the kernel with a bitset. The wakeup
function logically ANDs the bitset with the bitset stored in each
waiters futex_q structure. If the result is zero (i.e. none of the set
bits in the bitsets is matching), then the waiter is not woken up. If
the result is not zero (i.e. one of the set bits in the bitsets is
matching), then the waiter is woken.
The bitset provided by the caller must be non zero. In case the
provided bitset is zero the kernel returns EINVAL.
Internaly the new OPs are only extensions to the existing FUTEX_WAIT
and FUTEX_WAKE functions. The existing OPs hand a bitset with all bits
set into the futex_wait() and futex_wake() functions.
Signed-off-by: Thomas Gleixner <tgxl@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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