linux-stable.git/arch/um, branch v3.5

Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation"

2012-07-02T18:39:19+00:00

This reverts commit 616c310e83b872024271c915c1b9ab505b9efad9.
(Move PREEMPT_RCU preemption to switch_to() invocation).
Testing by Sasha Levin  showed that this
can result in deadlock due to invoking the scheduler when one of
the runqueue locks is held.  Because this commit was simply a
performance optimization, revert it.

Reported-by: Sasha Levin 
Signed-off-by: Paul E. McKenney 
Tested-by: Sasha Levin

new helper: signal_delivered()

2012-06-01T16:58:52+00:00

Does block_sigmask() + tracehook_signal_handler();  called when
sigframe has been successfully built.  All architectures converted
to it; block_sigmask() itself is gone now (merged into this one).

I'm still not too happy with the signature, but that's a separate
story (IMO we need a structure that would contain signal number +
siginfo + k_sigaction, so that get_signal_to_deliver() would fill one,
signal_delivered(), handle_signal() and probably setup...frame() -
take one).

Signed-off-by: Al Viro

most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set

2012-06-01T16:58:51+00:00

Only 3 out of 63 do not.  Renamed the current variant to __set_current_blocked(),
added set_current_blocked() that will exclude unblockable signals, switched
open-coded instances to it.

Signed-off-by: Al Viro

pull clearing RESTORE_SIGMASK into block_sigmask()

2012-06-01T16:58:49+00:00

Signed-off-by: Al Viro

new helper: sigmask_to_save()

2012-06-01T16:58:48+00:00

replace boilerplate "should we use ->saved_sigmask or ->blocked?"
with calls of obvious inlined helper...

Signed-off-by: Al Viro

new helper: restore_saved_sigmask()

2012-06-01T16:58:47+00:00

first fruits of ..._restore_sigmask() helpers: now we can take
boilerplate "signal didn't have a handler, clear RESTORE_SIGMASK
and restore the blocked mask from ->saved_mask" into a common
helper.  Open-coded instances switched...

Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2012-06-01T01:47:30+00:00

Pull second pile of signal handling patches from Al Viro:
 "This one is just task_work_add() series + remaining prereqs for it.

  There probably will be another pull request from that tree this
  cycle - at least for helpers, to get them out of the way for per-arch
  fixes remaining in the tree."

Fix trivial conflict in kernel/irq/manage.c: the merge of Andrew's pile
had brought in commit 97fd75b7b8e0 ("kernel/irq/manage.c: use the
pr_foo() infrastructure to prefix printks") which changed one of the
pr_err() calls that this merge moves around.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  keys: kill task_struct->replacement_session_keyring
  keys: kill the dummy key_replace_session_keyring()
  keys: change keyctl_session_to_parent() to use task_work_add()
  genirq: reimplement exit_irq_thread() hook via task_work_add()
  task_work_add: generic process-context callbacks
  avr32: missed _TIF_NOTIFY_RESUME on one of do_notify_resume callers
  parisc: need to check NOTIFY_RESUME when exiting from syscall
  move key_repace_session_keyring() into tracehook_notify_resume()
  TIF_NOTIFY_RESUME is defined on all targets now

um: properly check all process' threads for a live mm

2012-06-01T00:49:30+00:00

kill_off_processes() might miss a valid process, this is because checking
for process->mm is not enough.  Process' main thread may exit or detach
its mm via use_mm(), but other threads may still have a valid mm.

To catch this we use find_lock_task_mm(), which walks up all threads and
returns an appropriate task (with task lock held).

Suggested-by: Oleg Nesterov 
Signed-off-by: Anton Vorontsov 
Cc: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix possible race on task->mm

2012-06-01T00:49:30+00:00

Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
assigns NULL under task_lock(), so tasklist lock is not enough).

We can't use get_task_mm()/mmput() pair as mmput() might sleep, so let's
take the task lock while we care about its mm.

Note that we should also use find_lock_task_mm() to check all process'
threads for a valid mm, but for uml we'll do it in a separate patch.

Signed-off-by: Anton Vorontsov 
Cc: Richard Weinberger 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: should hold tasklist_lock while traversing processes

2012-06-01T00:49:30+00:00

Traversing the tasks requires holding tasklist_lock, otherwise it is
unsafe.

p.s.  However, I'm not sure that calling os_kill_ptraced_process() in the
atomic context is correct.  It seem to work, but please take a closer
look.

Signed-off-by: Anton Vorontsov 
Cc: Richard Weinberger 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds