27 May, 2009
1 commit
-
call_usermodehelper_setup() forgot to kfree(sub_info)
when prepare_usermodehelper_creds() failed.Signed-off-by: Tetsuo Handa
Signed-off-by: David Howells
Signed-off-by: Linus Torvalds
31 Mar, 2009
1 commit
-
There seems to be a common pattern in the kernel where drivers want to
call request_module() from inside a module_init() function. Currently
this would deadlock.As a result, several drivers go through hoops like scheduling things via
kevent, or creating custom work queues (because kevent can deadlock on them).This patch changes this to use a request_module_nowait() function macro instead,
which just fires the modprobe off but doesn't wait for it, and thus avoids the
original deadlock entirely.On my laptop this already results in one less kernel thread running..
(Includes Jiri's patch to use enum umh_wait)
Signed-off-by: Arjan van de Ven
Signed-off-by: Rusty Russell (bool-ified)
Cc: Jiri Slaby
30 Mar, 2009
1 commit
-
Impact: cleanup
(Thanks to Al Viro for reminding me of this, via Ingo)
CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so:
#define CPU_MASK_ALL (cpumask_t) { { ... } }
Taking the address of such a temporary is questionable at best,
unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added
CPU_MASK_ALL_PTR:#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
Which formalizes this practice. One day gcc could bite us over this
usage (though we seem to have gotten away with it so far).So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR
with the modern "cpu_all_mask" (a real const struct cpumask *).Signed-off-by: Rusty Russell
Acked-by: Ingo Molnar
Reported-by: Al Viro
Cc: Mike Travis
07 Jan, 2009
1 commit
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Fix varargs kernel-doc format in kmod.c:
Use @... instead of @varargs.Warning(kernel/kmod.c:67): Excess function parameter or struct member 'varargs' description in 'request_module'
Signed-off-by: Randy Dunlap
Acked-by: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Nov, 2008
2 commits
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Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).This patch and the preceding patches have been tested with the LTP SELinux
testsuite.This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()Changed. These now take cred pointers rather than task pointers to
refer to the security context.(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.Signed-off-by: David Howells
Acked-by: James Morris
Signed-off-by: James Morris -
Alter the use of the key instantiation and negation functions' link-to-keyring
arguments. Currently this specifies a keyring in the target process to link
the key into, creating the keyring if it doesn't exist. This, however, can be
a problem for copy-on-write credentials as it means that the instantiating
process can alter the credentials of the requesting process.This patch alters the behaviour such that:
(1) If keyctl_instantiate_key() or keyctl_negate_key() are given a specific
keyring by ID (ringid >= 0), then that keyring will be used.(2) If keyctl_instantiate_key() or keyctl_negate_key() are given one of the
special constants that refer to the requesting process's keyrings
(KEY_SPEC_*_KEYRING, all | Instantiator |------->| Instantiator |
| | | | | |
+-----------+ +--------------+ +--------------+
request_key() request_key()This might be useful, for example, in Kerberos, where the requestor requests a
ticket, and then the ticket instantiator requests the TGT, which someone else
then has to go and fetch. The TGT, however, should be retained in the
keyrings of the requestor, not the first instantiator. To make this explict
an extra special keyring constant is also added.Signed-off-by: David Howells
Reviewed-by: James Morris
Signed-off-by: James Morris
17 Oct, 2008
2 commits
-
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
module: remove CONFIG_KMOD in comment after #endif
remove CONFIG_KMOD from fs
remove CONFIG_KMOD from driversManually fix conflict due to include cleanups in drivers/md/md.c
-
We currently use a PM notifier to disable user mode helpers before suspend
and hibernation and to re-enable them during resume. However, this is not
an ideal solution, because if any drivers want to upload firmware into
memory before suspend, they have to use a PM notifier for this purpose and
there is no guarantee that the ordering of PM notifiers will be as
expected (ie. the notifier that disables user mode helpers has to be run
after the driver's notifier used for uploading the firmware).For this reason, it seems better to move the disabling and enabling of
user mode helpers to separate functions that will be called by the PM core
as necessary.[akpm@linux-foundation.org: remove unneeded ifdefs]
Signed-off-by: Rafael J. Wysocki
Cc: Alan Stern
Acked-by: Pavel Machek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Oct, 2008
1 commit
-
Signed-off-by: Rusty Russell
26 Jul, 2008
1 commit
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Presently call_usermodehelper_setup() uses GFP_ATOMIC. but it can return
NULL _very_ easily.GFP_ATOMIC is needed only when we can't sleep. and, GFP_KERNEL is robust
and better.thus, I add gfp_mask argument to call_usermodehelper_setup().
So, its callers pass the gfp_t as below:
call_usermodehelper() and call_usermodehelper_keys():
depend on 'wait' argument.
call_usermodehelper_pipe():
always GFP_KERNEL because always run under process context.
orderly_poweroff():
pass to GFP_ATOMIC because may run under interrupt context.Signed-off-by: KOSAKI Motohiro
Cc: "Paul Menage"
Reviewed-by: Li Zefan
Acked-by: Jeremy Fitzhardinge
Cc: Rusty Russell
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Jul, 2008
1 commit
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This patch adds O_NONBLOCK support to pipe2. It is minimally more involved
than the patches for eventfd et.al but still trivial. The interfaces of the
create_write_pipe and create_read_pipe helper functions were changed and the
one other caller as well.The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include
#include
#include
#include#ifndef __NR_pipe2
# ifdef __x86_64__
# define __NR_pipe2 293
# elif defined __i386__
# define __NR_pipe2 331
# else
# error "need __NR_pipe2"
# endif
#endifint
main (void)
{
int fds[2];
if (syscall (__NR_pipe2, fds, 0) == -1)
{
puts ("pipe2(0) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
printf ("pipe2(0) set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}if (syscall (__NR_pipe2, fds, O_NONBLOCK) == -1)
{
puts ("pipe2(O_NONBLOCK) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
printf ("pipe2(O_NONBLOCK) does not set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Signed-off-by: Ulrich Drepper
Acked-by: Davide Libenzi
Cc: Michael Kerrisk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Jul, 2008
1 commit
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Always compile request_module when the kernel allows modules.
Signed-off-by: Johannes Berg
Signed-off-by: Rusty Russell
02 May, 2008
1 commit
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Initial splitoff of the low-level stuff; taken to fdtable.h
Signed-off-by: Al Viro
20 Apr, 2008
1 commit
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* Use new set_cpus_allowed_ptr() function added by previous patch,
which instead of passing the "newly allowed cpus" cpumask_t arg
by value, pass it by pointer:-int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
+int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)* Modify CPU_MASK_ALL
Depends on:
[sched-devel]: sched: add new set_cpus_allowed_ptr functionSigned-off-by: Mike Travis
Signed-off-by: Ingo Molnar
15 Feb, 2008
1 commit
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This test seems to be unnecessary since we always have rootfs mounted before
calling a usermodehelper.Signed-off-by: Andreas Gruenbacher
Signed-off-by: Jan Blunck
Acked-by: Christoph Hellwig
Acked-by: Greg KH
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Jan, 2008
1 commit
-
call_usermodehelper_exec() has an exit path that can leave the
helper_lock() call at the top of the routine unbalanced. The attached
patch fixes this issue.Signed-off-by: Nigel Cunningham
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Sep, 2007
1 commit
-
The semantics of call_usermodehelper_pipe() used to be that it would fork
the helper, and wait for the kernel thread to be started. This was
implemented by setting sub_info.wait to 0 (implicitly), and doing a
wait_for_completion().As part of the cleanup done in 0ab4dc92278a0f3816e486d6350c6652a72e06c8,
call_usermodehelper_pipe() was changed to pass 1 as the value for wait to
call_usermodehelper_exec().This is equivalent to setting sub_info.wait to 1, which is a change from
the previous behaviour. Using 1 instead of 0 causes
__call_usermodehelper() to start the kernel thread running
wait_for_helper(), rather than directly calling ____call_usermodehelper().The end result is that the calling kernel code blocks until the user mode
helper finishes. As the helper is expecting input on stdin, and now no one
is writing anything, everything locks up (observed in do_coredump).The fix is to change the 1 to UMH_WAIT_EXEC (aka 0), indicating that we
want to wait for the kernel thread to be started, but not for the helper to
finish.Signed-off-by: Michael Ellerman
Acked-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2007
1 commit
-
Fix kmod.c:
Warning(linux-2.6.23-rc1//kernel/kmod.c:364): No description found for parameter 'envp'Signed-off-by: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Jul, 2007
2 commits
-
At present, if a user mode helper is running while
usermodehelper_pm_callback() is executed, the helper may be frozen and the
completion in call_usermodehelper_exec() won't be completed until user
space processes are thawed. As a result, the freezing of kernel threads
may fail, which is not desirable.Prevent this from happening by introducing a counter of running user mode
helpers and allowing usermodehelper_pm_callback() to succeed for action =
PM_HIBERNATION_PREPARE or action = PM_SUSPEND_PREPARE only if there are no
helpers running. [Namely, usermodehelper_pm_callback() waits for at most
RUNNING_HELPERS_TIMEOUT for the number of running helpers to become zero
and fails if that doesn't happen.]Special thanks to Uli Luckas , Pavel Machek
and Oleg Nesterov for reviewing the
previous versions of this patch and for very useful comments.Signed-off-by: Rafael J. Wysocki
Acked-by: Uli Luckas
Acked-by: Nigel Cunningham
Acked-by: Pavel Machek
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use a hibernation and suspend notifier to disable the user mode helper before
a hibernation/suspend and enable it after the operation.[akpm@linux-foundation.org: build fix]
Signed-off-by: Rafael J. Wysocki
Acked-by: Pavel Machek
Acked-by: Nigel Cunningham
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Jul, 2007
2 commits
-
Rather than using a tri-state integer for the wait flag in
call_usermodehelper_exec, define a proper enum, and use that. I've
preserved the integer values so that any callers I've missed should
still work OK.Signed-off-by: Jeremy Fitzhardinge
Cc: James Bottomley
Cc: Randy Dunlap
Cc: Christoph Hellwig
Cc: Andi Kleen
Cc: Paul Mackerras
Cc: Johannes Berg
Cc: Ralf Baechle
Cc: Bjorn Helgaas
Cc: Joel Becker
Cc: Tony Luck
Cc: Kay Sievers
Cc: Srivatsa Vaddagiri
Cc: Oleg Nesterov
Cc: David Howells -
Rather than having hundreds of variations of call_usermodehelper for
various pieces of usermode state which could be set up, split the
info allocation and initialization from the actual process execution.This means the general pattern becomes:
info = call_usermodehelper_setup(path, argv, envp); /* basic state */
call_usermodehelper_(info, stuff...); /* extra state */
call_usermodehelper_exec(info, wait); /* run process and free info */This patch introduces wrappers for all the existing calling styles for
call_usermodehelper_*, but folds their implementations into one.Signed-off-by: Jeremy Fitzhardinge
Cc: Andi Kleen
Cc: Rusty Russell
Cc: David Howells
Cc: Bj?rn Steinbrink
Cc: Randy Dunlap
10 May, 2007
2 commits
-
allow_signal(SIGCHLD) does all necessary job, no need to call do_sigaction()
prior to.Signed-off-by: Oleg Nesterov
Cc: Rusty Russell
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
____call_usermodehelper() has no reason for flush_signals(). It is a fresh
forked process which is going to exec a user-space application or exit on
failure.Signed-off-by: Oleg Nesterov
Cc: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 May, 2007
2 commits
-
Fix kevent's childs priority greediness. Such tasks were always scheduled
at nice level -5 and, at that time, udev stole us the CPU time with -5.Already posted at http://lkml.org/lkml/2005/1/10/85
[akpm@linux-foundation.org: add comment]
Signed-off-by: Jan Engelhardt
Cc: Chris Wright
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove includes of where it is not used/needed.
Suggested by Al Viro.Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).Signed-off-by: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Feb, 2007
2 commits
-
This reverts commit c353c3fb0700a3c17ea2b0237710a184232ccd7f.
It turns out that we end up with a loop trying to load the unix
module and calling netfilter to do that. Will redo the patch
later to not have this loop.Acked-by: Kay Sievers
Signed-off-by: Greg Kroah-Hartman -
This patch makes the needlessly global struct kmod_mk static.
Signed-off-by: Adrian Bunk
Signed-off-by: Greg Kroah-Hartman
17 Feb, 2007
1 commit
-
On recent systems, calls to /sbin/modprobe are handled by udev depending
on the kind of device the kernel has discovered. This patch creates an
uevent for the kernels internal request_module(), to let udev take control
over the request, instead of forking the binary directly by the kernel.
The direct execution of /sbin/modprobe can be disabled by setting:
/sys/module/kmod/mod_request_helper (/proc/sys/kernel/modprobe)
to an empty string, the same way /proc/sys/kernel/hotplug is disabled on an
udev system.Signed-off-by: Kay Sievers
Signed-off-by: Greg Kroah-Hartman
13 Feb, 2007
1 commit
-
When a machine check event is detected (including a AMD RevF threshold
overflow event) allow to run a "trigger" program. This allows user space
to react to such events sooner.The trigger is configured using a new trigger entry in the
machinecheck sysfs interface. It is currently shared between
all CPUs.I also fixed the AMD threshold handler to run the machine
check polling code immediately to actually log any events
that might have caused the threshold interrupt.Also added some documentation for the mce sysfs interface.
Signed-off-by: Andi Kleen
09 Dec, 2006
1 commit
-
Rename 'struct namespace' to 'struct mnt_namespace' to avoid confusion with
other namespaces being developped for the containers : pid, uts, ipc, etc.
'namespace' variables and attributes are also renamed to 'mnt_ns'Signed-off-by: Kirill Korotaev
Signed-off-by: Cedric Le Goater
Cc: Eric W. Biederman
Cc: Herbert Poetzl
Cc: Sukadev Bhattiprolu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Dec, 2006
1 commit
-
Conflicts:
drivers/infiniband/core/iwcm.c
drivers/net/chelsio/cxgb2.c
drivers/net/wireless/bcm43xx/bcm43xx_main.c
drivers/net/wireless/prism54/islpci_eth.c
drivers/usb/core/hub.h
drivers/usb/input/hid-core.c
net/core/netpoll.cFix up merge failures with Linus's head and fix new compilation failures.
Signed-Off-By: David Howells
29 Nov, 2006
1 commit
-
The return value of create_write_pipe()/create_read_pipe() should be
checked by IS_ERR().Signed-off-by: Akinobu Mita
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Nov, 2006
1 commit
-
Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.To make this work, an extra flag is introduced into the management side of the
work_struct. This governs auto-release of the structure upon execution.Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function. This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated.. This is a
problem if the auxiliary data is taken away (as done by the last patch).However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems. But then the work function must itself release the
work_struct by calling work_release().In most cases, automatic release is fine, so this is the default. Special
initiators exist for the non-auto-release case (ending in _NAR).Signed-Off-By: David Howells
02 Oct, 2006
1 commit
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The use of execve() in the kernel is dubious, since it relies on the
__KERNEL_SYSCALLS__ mechanism that stores the result in a global errno
variable. As a first step of getting rid of this, change all users to a
global kernel_execve function that returns a proper error code.This function is a terrible hack, and a later patch removes it again after the
kernel syscalls are gone.Signed-off-by: Arnd Bergmann
Cc: Andi Kleen
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Richard Henderson
Cc: Ivan Kokshaysky
Cc: Russell King
Cc: Ian Molton
Cc: Mikael Starvik
Cc: David Howells
Cc: Yoshinori Sato
Cc: Hirokazu Takata
Cc: Ralf Baechle
Cc: Kyle McMartin
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Paul Mundt
Cc: Kazumoto Kojima
Cc: Richard Curnow
Cc: William Lee Irwin III
Cc: "David S. Miller"
Cc: Jeff Dike
Cc: Paolo 'Blaisorblade' Giarrusso
Cc: Miles Bader
Cc: Chris Zankel
Cc: "Luck, Tony"
Cc: Geert Uytterhoeven
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Oct, 2006
2 commits
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Using the infrastructure created in previous patches implement support to
pipe core dumps into programs.This is done by overloading the existing core_pattern sysctl
with a new syntax:|program
When the first character of the pattern is a '|' the kernel will instead
threat the rest of the pattern as a command to run. The core dump will be
written to the standard input of that program instead of to a file.This is useful for having automatic core dump analysis without filling up
disks. The program can do some simple analysis and save only a summary of
the core dump.The core dump proces will run with the privileges and in the name space of
the process that caused the core dump.I also increased the core pattern size to 128 bytes so that longer command
lines fit.Most of the changes comes from allowing core dumps without seeks. They are
fairly straight forward though.One small incompatibility is that if someone had a core pattern previously
that started with '|' they will get suddenly new behaviour. I think that's
unlikely to be a real problem though.Additional background:
> Very nice, do you happen to have a program that can accept this kind of
> input for crash dumps? I'm guessing that the embedded people will
> really want this functionality.I had a cheesy demo/prototype. Basically it wrote the dump to a file again,
ran gdb on it to get a backtrace and wrote the summary to a shared directory.
Then there was a simple CGI script to generate a "top 10" crashes HTML
listing.Unfortunately this still had the disadvantage to needing full disk space for a
dump except for deleting it afterwards (in fact it was worse because over the
pipe holes didn't work so if you have a holey address map it would require
more space).Fortunately gdb seems to be happy to handle /proc/pid/fd/xxx input pipes as
cores (at least it worked with zsh's =(cat core) syntax), so it would be
likely possible to do it without temporary space with a simple wrapper that
calls it in the right way. I ran out of time before doing that though.The demo prototype scripts weren't very good. If there is really interest I
can dig them out (they are currently on a laptop disk on the desk with the
laptop itself being in service), but I would recommend to rewrite them for any
serious application of this and fix the disk space problem.Also to be really useful it should probably find a way to automatically fetch
the debuginfos (I cheated and just installed them in advance). If nobody else
does it I can probably do the rewrite myself again at some point.My hope at some point was that desktops would support it in their builtin
crash reporters, but at least the KDE people I talked too seemed to be happy
with their user space only solution.Alan sayeth:
I don't believe that piping as such as neccessarily the right model, but
the ability to intercept and processes core dumps from user space is asked
for by many enterprise users as well. They want to know about, capture,
analyse and process core dumps, often centrally and in automated form.[akpm@osdl.org: loff_t != unsigned long]
Signed-off-by: Andi Kleen
Cc: Alan Cox
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A new member in the ever growing family of call_usermode* functions is
born. The new call_usermodehelper_pipe() function allows to pipe data to
the stdin of the called user mode progam and behaves otherwise like the
normal call_usermodehelp() (except that it always waits for the child to
finish)Signed-off-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Sep, 2006
1 commit
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If ____call_usermodehelper fails, we're not interested in the child
process' exit value, but the real error, so let's stop wait_for_helper from
overwriting it in that case.Issue discovered by Benedikt Böhm while working on a Linux-VServer usermode
helper.Signed-off-by: Björn Steinbrink
Cc: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Sep, 2006
1 commit
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I think there is a bug in kmod.c: In __call_usermodehelper(), when
kernel_thread(wait_for_helper, ...) return success, since wait_for_helper()
might call complete() at any time, the sub_info should not be used any
more.Normally wait_for_helper() take a long time to finish, you may not get
problem for most of the case. But if you remove /sbin/modprobe, it may
become easier for you to get a oop in khelper.Cc: Matt Helsley
Cc: Martin Schwidefsky
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Jul, 2006
1 commit
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lockdep needs to have the waitqueue lock initialized for on-stack waitqueues
implicitly initialized by DECLARE_COMPLETION(). Annotate on-stack completions
accordingly.Has no effect on non-lockdep kernels.
Signed-off-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
