into samba.org:/scratch/anton/sfr

This fixes the signal code to not wake up threads with blocked signals,
especially noticeable with kernel threads that may not be able to handle
signals at all.

We also don't unnecessarily wake processes in TASK_UNINTERRUPTIBLE.

Sound drivers need <linus/interrupt.h> for tasklets

  - emu10k1 - fixed makefile to not build synth module when emu10k1 is not selected

  - cmipci driver cleanups (ac3 & surround)
  - replaced snd_dma_residue() with snd_dma_pointer()
  - GCC 3.3 warnings removal
  - timer interface
    - recoded using tasklet
    - improved slave timer locking (should be much faster)
    - added async support
  - improved ioctl32 wrapper functions
  - fixed Makefile problems (synth modules were build for not selected driver)
  - AC97 codec
    - improved SPSA control
    - moved reset function outside the main init code
    - improved ALC650 initialization
  - USB driver
    - added quirk for Roland XV-2020

For handle_stop_signal to do the special case for SIGKILL and have it
work right in all SMP cases (without changing all the existing ptrace
stops), it needs to at least set TIF_SIGPENDING on each thread before
resuming it.

handle_stop_signal addresses a related race for SIGCONT by setting
TIF_SIGPENDING already, so having SIGKILL handled the same way makes
sense.

Now it seems pretty clean to have handle_stop_signal resume threads for
SIGKILL, and have on SIGKILL special case in group_send_sig_info.

There is also an SMP race issue with cases like do_syscall_trace, i.e.
TASK_STOPPED state set without holding the siglock.  So I think
handle_stop_signal should call wake_up_process unconditionally.

Accomodate the signal locking moving from "tsk->sig" to "tsk->sighand".

into samba.org:/scratch/anton/sfr

This is required to get make the old LinuxThread semantics work
together with the fixed-for-POSIX full signal sharing. A traditional
CLONE_SIGHAND thread (LinuxThread) will not see any other shared
signal state, while a new-style CLONE_THREAD thread will share all
of it.

This way the two methods don't confuse each other.

already take care of it.

This fixes kernel threads that _do_ block SIGKILL/STOP.

into samba.org:/scratch/anton/sfr

Spotted by davem.  Strange that it ever worked.  Don't know why the compiler
didn't warn...

This changes do_sigaction to avoid read_lock(&tasklist_lock) on every
call.  Only in the fairly uncommon cases where it's really needed will
it take that lock (which requires unlocking and relocking the siglock
for locking order).

I also changed the ERESTARTSYS added in my earlier patch to ERESTARTNOINTR.
That is an "instantaneous" case, and there is no reason to have it possibly
return EINTR if !SA_RESTART (which AFAIK sigaction never could before, and
it might not be kosher by POSIX); rollback is always better.

This patch removes all the comments on the SA_NOCLDWAIT definitions,
since SA_NOCLDWAIT is fully supported now.

This fixes the following common misspellings and their variants.

  consistant -> consistent
  dependant  -> dependent
  persistant -> persistent

into samba.org:/scratch/anton/sfr

into samba.org:/scratch/anton/sfr

into samba.org:/scratch/anton/sfr

Here is a cleanup moving the new pending thread signal check into
exit_notify.

I also made exit_notify and do_exit consistent in using the saved tsk
variable instead of current, as most of do_exit already does.

Add a missing include for those pesky S_IRUGO thingys.

This patch for bt819.c addresses buzilla bug #169 (compile error).

This patch to saa7185 to resolves buzilla bug #168 (compile error).  It
has been sent to l-k and has received no objections.

This fixes a bt856.c compile error.  The driver now compiles.  Its a
straightforward patch and have emailed l-k and no objections have been
reported.

The Stanford checker disclose that vxfs_read_fshead was missing any
unwinding in the error cases..

In struct char_dev the fields openers and sem are unused.
The file char_dev.c claims that it is called differently.

hm.  It seems that I sent this patch twice.

After resyncing with your tree I go through and try to reapply all the sent
patches, throwing out the ones which get a lot of rejects.  Just to make sure
that everything got through OK.

But it appears that that particular patch happily applied on top of itself,
so I assumed it was not applied...

I cleaned up sys_wait4; it was straightforward and I think a definite
improvement.  While at it, I noticed that one of the races I fixed in the
TASK_STOPPED case actually can happen earlier.  Between read_unlock and
write_lock_irq, another thread could reap the process and make P invalid,
so now I do get_task_struct before read_unlock and then the existing race
checks catch all scenarios.

Aside from the aforementioned race tweak, the code should be the same as
in the previous patch (that Ingo and I have tested more thoroughly)
modulo being moved into functions and some reformatting and comment
changes.

Oh, my old patch had one case where it failed to retake the read lock after
a race bailout that I just noticed reading over it.  That's fixed too.

These exit fixes were something I noticed incidentally and spent less time
on than the signals changes.  Another few passes of eyeballs over them are
certainly warranted.  (In particular, there are code paths like that one
that check for specific races that have probably never been seen in
practice, so those code paths have never run once.)

OK, here is the diff against 2.5.59-bk2, now up to 880 lines due to an
additional misspelling which crept in the -bk2 snapshot.

Fixes 'seperate' -> 'separate' and 'definate' -> 'definite'.

Kernal codrs cna't spel.

The CLEAR_BITMAP() macro in include/linux/types.h is broken and doesn't
round the bitmap size to the proper 'long' boundary.

This fixes it by creating a macro BITS_TO_LONGS that just rounds a
number of bits up to the closest number of unsigned longs.  This makes
the DECLARE & CLEAR _BITMAP macros more readable and fixes the bug.

This moves access of the host element to device since host has been
removed from struct scsi_cmnd.

this is the current threading patchset, which accumulated up during the
past two weeks. It consists of a biggest set of changes from Roland, to
make threaded signals work. There were still tons of testcases and
boundary conditions (mostly in the signal/exit/ptrace area) that we did
not handle correctly.

Roland's thread-signal semantics/behavior/ptrace fixes:

 - fix signal delivery race with do_exit() => signals are re-queued to the
   'process' if do_exit() finds pending unhandled ones. This prevents
   signals getting lost upon thread-sys_exit().

 - a non-main thread has died on one processor and gone to TASK_ZOMBIE,
   but before it's gotten to release_task a sys_wait4 on the other
   processor reaps it.  It's only because it's ptraced that this gets
   through eligible_child.  Somewhere in there the main thread is also
   dying so it reparents the child thread to hit that case.  This means
   that there is a race where P might be totally invalid.

 - forget_original_parent is not doing the right thing when the group
   leader dies, i.e. reparenting threads to init when there is a zombie
   group leader.  Perhaps it doesn't matter for any practical purpose
   without ptrace, though it makes for ppid=1 for each thread in core
   dumps, which looks funny. Incidentally, SIGCHLD here really should be
   p->exit_signal.

 - one of the gdb tests makes a questionable assumption about what kill
   will do when it has some threads stopped by ptrace and others running.

exit races:

1. Processor A is in sys_wait4 case TASK_STOPPED considering task P.
   Processor B is about to resume P and then switch to it.

   While A is inside that case block, B starts running P and it clears
   P->exit_code, or takes a pending fatal signal and sets it to a new
   value. Depending on the interleaving, the possible failure modes are:
        a. A gets to its put_user after B has cleared P->exit_code
           => returns with WIFSTOPPED, WSTOPSIG==0
        b. A gets to its put_user after B has set P->exit_code anew
           => returns with e.g. WIFSTOPPED, WSTOPSIG==SIGKILL

   A can spend an arbitrarily long time in that case block, because
   there's getrusage and put_user that can take page faults, and
   write_lock'ing of the tasklist_lock that can block.  But even if it's
   short the race is there in principle.

2. This is new with NPTL, i.e. CLONE_THREAD.
   Two processors A and B are both in sys_wait4 case TASK_STOPPED
   considering task P.

   Both get through their tests and fetches of P->exit_code before either
   gets to P->exit_code = 0.  => two threads return the same pid from
   waitpid.

   In other interleavings where one processor gets to its put_user after
   the other has cleared P->exit_code, it's like case 1(a).


3. SMP races with stop/cont signals

   First, take:

        kill(pid, SIGSTOP);
        kill(pid, SIGCONT);

   or:

        kill(pid, SIGSTOP);
        kill(pid, SIGKILL);

   It's possible for this to leave the process stopped with a pending
   SIGCONT/SIGKILL.  That's a state that should never be possible.
   Moreover, kill(pid, SIGKILL) without any repetition should always be
   enough to kill a process.  (Likewise SIGCONT when you know it's
   sequenced after the last stop signal, must be sufficient to resume a
   process.)

4. take:

        kill(pid, SIGKILL);     // or any fatal signal
        kill(pid, SIGCONT);     // or SIGKILL

    it's possible for this to cause pid to be reaped with status 0
    instead of its true termination status.  The equivalent scenario
    happens when the process being killed is in an _exit call or a
    trap-induced fatal signal before the kills.

plus i've done stability fixes for bugs that popped up during
beta-testing, and minor tidying of Roland's changes:

 - a rare tasklist corruption during exec, causing some very spurious and
   colorful crashes.

 - a copy_process()-related dereference of already freed thread structure
   if hit with a SIGKILL in the wrong moment.

 - SMP spinlock deadlocks in the signal code

this patchset has been tested quite well in the 2.4 backport of the
threading changes - and i've done some stresstesting on 2.5.59 SMP as
well, and did an x86 UP testcompile + testboot as well.