lkml.org 
[lkml]   [2014]   [Oct]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.10 143/143] vm_is_stack: use for_each_thread() rather then buggy while_each_thread()
    Date
    3.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Oleg Nesterov <oleg@redhat.com>

    commit 4449a51a7c281602d3a385044ab928322a122a02 upstream.

    Aleksei hit the soft lockup during reading /proc/PID/smaps. David
    investigated the problem and suggested the right fix.

    while_each_thread() is racy and should die, this patch updates
    vm_is_stack().

    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    Reported-by: Aleksei Besogonov <alex.besogonov@gmail.com>
    Tested-by: Aleksei Besogonov <alex.besogonov@gmail.com>
    Suggested-by: David Rientjes <rientjes@google.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Li Zefan <lizefan@huawei.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    mm/util.c | 9 +++------
    1 file changed, 3 insertions(+), 6 deletions(-)

    --- a/mm/util.c
    +++ b/mm/util.c
    @@ -272,17 +272,14 @@ pid_t vm_is_stack(struct task_struct *ta

    if (in_group) {
    struct task_struct *t;
    - rcu_read_lock();
    - if (!pid_alive(task))
    - goto done;

    - t = task;
    - do {
    + rcu_read_lock();
    + for_each_thread(task, t) {
    if (vm_is_stack_for_task(t, vma)) {
    ret = t->pid;
    goto done;
    }
    - } while_each_thread(task, t);
    + }
    done:
    rcu_read_unlock();
    }



    \
     
     \ /
      Last update: 2014-10-04 01:21    [W:4.071 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site