Doug / smarc-fsl-linux-kernel

10 May, 2007

2 commits

  • 10ab825bd   change kernel threads to ignore signals instead of blocking them ... Browse Code »

    Currently kernel threads use sigprocmask(SIG_BLOCK) to protect against
    signals. This doesn't prevent the signal delivery, this only blocks
    signal_wake_up(). Every "killall -33 kthreadd" means a "struct siginfo"
    leak.

    Change kthreadd_setup() to set all handlers to SIG_IGN instead of blocking
    them (make a new helper ignore_signals() for that). If the kernel thread
    needs some signal, it should use allow_signal() anyway, and in that case it
    should not use CLONE_SIGHAND.

    Note that we can't change daemonize() (should die!) in the same way,
    because it can be used along with CLONE_SIGHAND. This means that
    allow_signal() still should unblock the signal to work correctly with
    daemonize()ed threads.

    However, disallow_signal() doesn't block the signal any longer but ignores
    it.

    NOTE: with or without this patch the kernel threads are not protected from
    handle_stop_signal(), this seems harmless, but not good.

    Signed-off-by: Oleg Nesterov
    Acked-by: "Eric W. Biederman"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • 73c279927   kthread: don't depend on work queues ... Browse Code »

    Currently there is a circular reference between work queue initialization
    and kthread initialization. This prevents the kthread infrastructure from
    initializing until after work queues have been initialized.

    We want the properties of tasks created with kthread_create to be as close
    as possible to the init_task and to not be contaminated by user processes.
    The later we start our kthreadd that creates these tasks the harder it is
    to avoid contamination from user processes and the more of a mess we have
    to clean up because the defaults have changed on us.

    So this patch modifies the kthread support to not use work queues but to
    instead use a simple list of structures, and to have kthreadd start from
    init_task immediately after our kernel thread that execs /sbin/init.

    By being a true child of init_task we only have to change those process
    settings that we want to have different from init_task, such as our process
    name, the cpus that are allowed, blocking all signals and setting SIGCHLD
    to SIG_IGN so that all of our children are reaped automatically.

    By being a true child of init_task we also naturally get our ppid set to 0
    and do not wind up as a child of PID == 1. Ensuring that tasks generated
    by kthread_create will not slow down the functioning of the wait family of
    functions.

    [akpm@linux-foundation.org: use interruptible sleeps]
    Signed-off-by: Eric W. Biederman
    Cc: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Eric W. Biederman
     

12 Feb, 2007

1 commit

  • 72fd4a35a   [PATCH] Numerous fixes to kernel-doc info in source files. ... Browse Code »

    A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
    source files, including:

    * make multi-line initial descriptions single line
    * denote some function names, constants and structs as such
    * change erroneous opening '/*' to '/**' in a few places
    * reword some text for clarity

    Signed-off-by: Robert P. J. Day
    Cc: "Randy.Dunlap"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Robert P. J. Day
     

22 Nov, 2006

1 commit

  • 65f27f384   WorkStruct: Pass the work_struct pointer instead of context data ... Browse Code »

    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

    David Howells
     

15 Jul, 2006

1 commit

26 Jun, 2006

1 commit

26 Mar, 2006

1 commit

  • 05eeae208   [PATCH] find_task_by_pid() needs tasklist_lock ... Browse Code »

    A couple of places are forgetting to take it.

    The kswapd case is probably unimportant. keventd_create_kthread() was racy.

    The whole thing is a bit flakey: you start a kernel thread, get its pid from
    kernel_thread() then look up its task_struct.

    a) It assumes that pid recycling takes a "long" time.

    b) We get a task_struct but no reference was taken on it. The owner of the
    kswapd and kthread task_struct*'s must assume that the new thread won't
    exit unexpectedly. Because if it does, they're left holding dead memory
    and any attempt to control or stop that task will crash.

    Cc: Christoph Hellwig
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrew Morton
     

23 Mar, 2006

1 commit

  • 97d1f15b7   [PATCH] sem2mutex: kernel/ ... Browse Code »

    Semaphore to mutex conversion.

    The conversion was generated via scripts, and the result was validated
    automatically via a script as well.

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arjan van de Ven
     

31 Oct, 2005

1 commit

  • 61e1a9ea4   [PATCH] Add kthread_stop_sem() ... Browse Code »

    Enhance the kthread API by adding kthread_stop_sem, for use in stopping
    threads that spend their idle time waiting on a semaphore.

    Signed-off-by: Alan Stern
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Stern
     

01 May, 2005

1 commit

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    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!

    Linus Torvalds