linux-toradex.git/kernel/kmod.c, branch v2.6.25-rc2

Dont touch fs_struct in usermodehelper

2008-02-15T05:13:32+00:00

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

Fix unbalanced helper_lock in kernel/kmod.c

2008-01-17T23:38:59+00:00

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

Restore call_usermodehelper_pipe() behaviour

2007-09-12T00:21:20+00:00

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

kernel-doc fix for kmod.c

2007-07-26T18:33:06+00:00

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

PM: prevent frozen user mode helpers from failing the freezing of tasks

2007-07-19T17:04:42+00:00

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

PM: disable usermode helper before hibernation and suspend

2007-07-19T17:04:42+00:00

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

usermodehelper: Tidy up waiting

2007-07-18T15:47:40+00:00

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

usermodehelper: split setup from execution

2007-07-18T15:47:40+00:00

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

wait_for_helper: remove unneeded do_sigaction()

2007-05-09T19:30:53+00:00

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: don't flush_signals()

2007-05-09T19:30:53+00:00

____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