The problem. It is expected that /sbin/halt -p works exactly like
/sbin/halt, when the kernel does not implement power off functionality.
The kernel can do a lot of work in the reboot notifiers and in
device_shutdown before we even get to machine_power_off. Some of that
shutdown is not safe if you are leaving the power on, and it definitely
gets in the way of using sysrq or pressing ctrl-alt-del. Since the
shutdown happens in generic code there is no way to fix this in
architecture specific code :(
Some machines are kernel oopsing today because of this.
The simple solution is to turn LINUX_REBOOT_CMD_POWER_OFF into
LINUX_REBOOT_CMD_HALT if power_off functionality is not implemented.
This has the unfortunate side effect of disabling the power off
functionality on architectures that leave pm_power_off to null and still
implement something in machine_power_off. And it will break the build on
some architectures that don't have a pm_power_off variable at all.
On both counts I say tough.
For architectures like alpha that don't implement the pm_power_off variable
pm_power_off is declared in linux/pm.h and it is a generic part of our
power management code, and all architectures should implement it.
For architectures like parisc that have a default power off method in
machine_power_off if pm_power_off is not implemented or fails. It is easy
enough to set the pm_power_off variable. And nothing bad happens there,
the machines just stop powering off.
The current semantics are impossible without a flag at the top level so we
can avoid the problem code if a power off is not implemented. pm_power_off
is as good a flag as any with the bonus that it works without modification
on at least x86, x86_64, powerpc, and ppc today.
Andrew can you pick this up and put this in the mm tree. Kernels that
don't compile or don't power off seem saner than kernels that oops or
panic. Until we get the arch specific patches for the problem
architectures this probably isn't smart to push into the stable kernel.
Unfortunately I don't have the time at the moment to walk through every
architecture and make them work. And even if I did I couldn't test it :(
From: Hirokazu Takata <takata@linux-m32r.org>
Add pm_power_off() for build fix of arch/m32r/kernel/process.c.
From: Miklos Szeredi <miklos@szeredi.hu>
UML build fix
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Hayato Fujiwara <fujiwara@linux-m32r.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For Kprobes critical path is the path from debug break exception handler
till the control reaches kprobes exception code. No probes can be
supported in this path as we will end up in recursion.
This patch prevents this by moving the below function to safe __kprobes
section onto which no probes can be inserted.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I didn't find any possible modular usage in the kernel.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Convert to proper kernel-doc format.
Some have extra blank lines (not allowed immed. after the function name)
or need blank lines (after all parameters). Function summary must be only
one line.
Colon (":") in a function description does weird things (causes kernel-doc
to think that it's a new section head sadly).
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Various core kernel-doc cleanups:
- add missing function parameters in ipc, irq/manage, kernel/sys,
kernel/sysctl, and mm/slab;
- move description to just above function for kernel_restart()
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds a connector that reports fork, exec, id change, and exit
events for all processes to userspace. It replaces the fork_advisor patch
that ELSA is currently using. Applications that may find these events
useful include accounting/auditing (e.g. ELSA), system activity monitoring
(e.g. top), security, and resource management (e.g. CKRM).
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the lead up to 2.6.13 I fixed a large number of reboot problems by
making the calling conventions consistent. Despite checking and double
checking my work it appears I missed an obvious one.
This first patch simply refactors the reboot routines so all of the
preparation for various kinds of reboots are in their own functions.
Making it very hard to get the various kinds of reboot out of sync.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2.6.13 incorporated Alan Cox's patch for /proc/sys/fs/suid_dumpable (one
version of this patch can be found here
http://marc.theaimsgroup.com/?l=linux-kernel&m=109647550421014&w=2 ).
This patch also made corresponding changes in kernel/sys.c to change the
prctl() PR_SET_DUMPABLE operation so that the permitted range of 'arg2' was
modified from 0..1 to 0..2.
However, a corresponding change was not made for PR_GET_DUMPABLE: if the
dumpable flag is non-zero, then PR_GET_DUMPABLE always returns 1, so that
the caller can't determine the true setting of this flag.
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The patch removes a redundant variable `sig' from sys_prctl().
For some reason, when sys_prctl is called with option == PR_SET_PDEATHSIG
then the value of arg2 is assigned to an int variable named sig. Then sig
is tested with valid_signal() and later used to set the value of
current->pdeath_signal .
There is no reason to use this intermediate variable since valid_signal()
takes a unsigned long argument, so it can handle being passed arg2
directly, and if the call to valid_signal is OK, then we know the value of
arg2 is in the range zero to _NSIG and thus it'll easily fit in a plain int
and thus there's no problem assigning it later to current->pdeath_signal
(which is an int).
The patch gets rid of the pointless variable `sig'.
This reduces the size of kernel/sys.o in 2.6.13-rc6-mm1 by 32 bytes on my
system.
Patch has been compile tested, boot tested, and just to make damn sure I
didn't break anything I wrote a quick test app that calls
prctl(PR_SET_PDEATHSIG ...) with the entire range of values for a
unsigned long, and it behaves as expected with and without the patch.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This removes the calls to device_suspend() from the shutdown path that
were added sometime during 2.6.13-rc*. They aren't working properly on
a number of configs (I got reports from both ppc powerbook users and x86
users) causing the system to not shutdown anymore.
I think it isn't the right approach at the moment anyway. We have
already a shutdown() callback for the drivers that actually care about
shutdown and the suspend() code isn't yet in a good enough shape to be
so much generalized. Also, the semantics of suspend and shutdown are
slightly different on a number of setups and the way this was patched in
provides little way for drivers to cleanly differenciate. It should
have been at least a different message.
For 2.6.13, I think we should revert to 2.6.12 behaviour and have a
working suspend back.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If device_suspend(PMSG_FREEZE) is not ready to be called in
kernel_restart it is definitely not ready to be called in the even more
fickle kernel_kexec.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
My fairly ordinary x86 test box gets stuck during reboot on the
wait_for_completion() in ide_do_drive_cmd():
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When the kernel is working well and we want to restart cleanly
kernel_restart is the function to use. But in many instances
the kernel wants to reboot when thing are expected to be working
very badly such as from panic or a software watchdog handler.
This patch adds the function emergency_restart() so that
callers can be clear what semantics they expect when calling
restart. emergency_restart() is expected to be callable
from interrupt context and possibly reliable in even more
trying circumstances.
This is an initial generic implementation for all architectures.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is obvious we wanted to call kernel_restart here
but since we don't have it the code was expanded inline and hasn't
been correct since sometime in 2.4.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Because the factors of sys_reboot don't exist people calling
into the reboot path duplicate the code badly, leading to
inconsistent expectations of code in the reboot path.
This patch should is just code motion.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the recent addition of device_suspend calls into
sys_reboot two code paths were missed.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch introduces the architecture independent implementation the
sys_kexec_load, the compat_sys_kexec_load system calls.
Kexec on panic support has been integrated into the core patch and is
relatively clean.
In addition the hopefully architecture independent option
crashkernel=size@location has been docuemented. It's purpose is to reserve
space for the panic kernel to live, and where no DMA transfer will ever be
setup to access.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Alexander Nyberg <alexn@telia.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Without this patch, Linux provokes emergency disk shutdowns and
similar nastiness. It was in SuSE kernels for some time, IIRC.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The attached patch makes the following changes:
(1) There's a new special key type called ".request_key_auth".
This is an authorisation key for when one process requests a key and
another process is started to construct it. This type of key cannot be
created by the user; nor can it be requested by kernel services.
Authorisation keys hold two references:
(a) Each refers to a key being constructed. When the key being
constructed is instantiated the authorisation key is revoked,
rendering it of no further use.
(b) The "authorising process". This is either:
(i) the process that called request_key(), or:
(ii) if the process that called request_key() itself had an
authorisation key in its session keyring, then the authorising
process referred to by that authorisation key will also be
referred to by the new authorisation key.
This means that the process that initiated a chain of key requests
will authorise the lot of them, and will, by default, wind up with
the keys obtained from them in its keyrings.
(2) request_key() creates an authorisation key which is then passed to
/sbin/request-key in as part of a new session keyring.
(3) When request_key() is searching for a key to hand back to the caller, if
it comes across an authorisation key in the session keyring of the
calling process, it will also search the keyrings of the process
specified therein and it will use the specified process's credentials
(fsuid, fsgid, groups) to do that rather than the calling process's
credentials.
This allows a process started by /sbin/request-key to find keys belonging
to the authorising process.
(4) A key can be read, even if the process executing KEYCTL_READ doesn't have
direct read or search permission if that key is contained within the
keyrings of a process specified by an authorisation key found within the
calling process's session keyring, and is searchable using the
credentials of the authorising process.
This allows a process started by /sbin/request-key to read keys belonging
to the authorising process.
(5) The magic KEY_SPEC_*_KEYRING key IDs when passed to KEYCTL_INSTANTIATE or
KEYCTL_NEGATE will specify a keyring of the authorising process, rather
than the process doing the instantiation.
(6) One of the process keyrings can be nominated as the default to which
request_key() should attach new keys if not otherwise specified. This is
done with KEYCTL_SET_REQKEY_KEYRING and one of the KEY_REQKEY_DEFL_*
constants. The current setting can also be read using this call.
(7) request_key() is partially interruptible. If it is waiting for another
process to finish constructing a key, it can be interrupted. This permits
a request-key cycle to be broken without recourse to rebooting.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-Off-By: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Avoid taking the tasklist_lock in sys_times if the process is single
threaded. In a NUMA system taking the tasklist_lock may cause a bouncing
cacheline if multiple independent processes continually call sys_times to
measure their performance.
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a new `suid_dumpable' sysctl:
This value can be used to query and set the core dump mode for setuid
or otherwise protected/tainted binaries. The modes are
0 - (default) - traditional behaviour. Any process which has changed
privilege levels or is execute only will not be dumped
1 - (debug) - all processes dump core when possible. The core dump is
owned by the current user and no security is applied. This is intended
for system debugging situations only. Ptrace is unchecked.
2 - (suidsafe) - any binary which normally would not be dumped is dumped
readable by root only. This allows the end user to remove such a dump but
not access it directly. For security reasons core dumps in this mode will
not overwrite one another or other files. This mode is appropriate when
adminstrators are attempting to debug problems in a normal environment.
(akpm:
> > +EXPORT_SYMBOL(suid_dumpable);
>
> EXPORT_SYMBOL_GPL?
No problem to me.
> > if (current->euid == current->uid && current->egid == current->gid)
> > current->mm->dumpable = 1;
>
> Should this be SUID_DUMP_USER?
Actually the feedback I had from last time was that the SUID_ defines
should go because its clearer to follow the numbers. They can go
everywhere (and there are lots of places where dumpable is tested/used
as a bool in untouched code)
> Maybe this should be renamed to `dump_policy' or something. Doing that
> would help us catch any code which isn't using the #defines, too.
Fair comment. The patch was designed to be easy to maintain for Red Hat
rather than for merging. Changing that field would create a gigantic
diff because it is used all over the place.
)
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As per http://www.nist.gov/dads/HTML/shellsort.html, this should be
referred to as a Shell sort. Shell-Metzner is a misnomer.
Signed-off-by: Daniel Dickman <didickman@yahoo.com>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Convert most of the current code that uses _NSIG directly to instead use
valid_signal(). This avoids gcc -W warnings and off-by-one errors.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a pair of rlimits for allowing non-root tasks to raise nice and rt
priorities. Defaults to traditional behavior. Originally written by
Chris Wright.
The patch implements a simple rlimit ceiling for the RT (and nice) priorities
a task can set. The rlimit defaults to 0, meaning no change in behavior by
default. A value of 50 means RT priority levels 1-50 are allowed. A value of
100 means all 99 privilege levels from 1 to 99 are allowed. CAP_SYS_NICE is
blanket permission.
(akpm: see http://www.uwsg.iu.edu/hypermail/linux/kernel/0503.1/1921.html for
tips on integrating this with PAM).
Signed-off-by: Matt Mackall <mpm@selenic.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace a number of memory barriers with smp_ variants. This means we won't
take the unnecessary hit on UP machines.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Eric W. Biederman