1. 12 Aug, 2009 1 commit
    • Nils Carlson's avatar
      The periodic interrupt from drivers/char/hpet.c does not work correctly, · 7a6c798b
      Nils Carlson authored
      both when using the periodic capability of the hardware and while
      emulating the periodic interrupt (when hardware does not support periodic
      mode).
      
      With timers capable of periodic interrupts, the comparator field is first
      set with the period value followed by set of hidden accumulator, which has
      the side effect of overwriting the comparator value.  This results in
      wrong periodicity for the interrupts.  For, periodic interrupts to work,
      following steps are necessary, in that order.
      
      * Set config with Tn_VAL_SET_CNF bit
      
      * Write to hidden accumulator, the value written is the time when the
        first interrupt should be generated
      
      * Write compartor with period interval for subsequent interrupts
        (http://www.intel.com/hardwaredesign/hpetspec_1.pdf )
      
      When emulating periodic timer with timers not capable of periodic
      interrupt, driver is adding the period to counter value instead of
      comparator value, which causes slow drift when using this emulation.
      
      Also, driver seems to add hpetp->hp_delta both while setting up periodic
      interrupt and while emulating periodic interrupts with timers not capable
      of doing periodic interrupts.  This hp_delta will result in slower than
      expected interrupt rate and should not be used while setting the interval.
      Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
      Signed-off-by: default avatarNils Carlson <nils.carlson@ericsson.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      7a6c798b
  2. 04 Aug, 2009 1 commit
  3. 24 Aug, 2009 2 commits
  4. 18 Aug, 2009 1 commit
    • Renzo Davoli's avatar
      There are two useless lines in fs/char_dev.c. · 5529cb8a
      Renzo Davoli authored
      In register_chrdev there is a loop to change all '/' into '!' in the
      kernel object name.
      This code is useless as the same substitution is in kobject_set_name_vargs in
      lib/kobject.c:
      228         /* ewww... some of these buggers have '/' in the name ... */
      229         while ((s = strchr(kobj->name, '/')))
      230                 s[0] = '!';
      
      kobject_set_name_vargs is called by kobject_set_name.
      kobject_set_name is called just above the useless loop.
      Signed-off-by: default avatarRenzo Davoli <renzo@cs.unibo.it>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      5529cb8a
  5. 21 Jul, 2009 1 commit
  6. 02 Jul, 2009 1 commit
  7. 20 Jul, 2009 1 commit
  8. 01 Jul, 2009 2 commits
  9. 23 Jul, 2009 1 commit
    • Lai Jiangshan's avatar
      _cpu_down() changes the current task's affinity and then recovers it at · 0fdcbb46
      Lai Jiangshan authored
      the end.
      
      It has two problems:
      
      1) The recovery of the current tasks's cpus_allowed will fail under
         some conditions.
      
         # grep Cpus_allowed_list /proc/$$/status
         Cpus_allowed_list:      0-3
      
         # taskset -pc 2 $$
         pid 29075's current affinity list: 0-3
         pid 29075's new affinity list: 2
      
         # grep Cpus_allowed_list /proc/$$/status
         Cpus_allowed_list:      2
      
         # echo 0 > /sys/devices/system/cpu/cpu2/online
      
         # grep Cpus_allowed_list /proc/$$/status
         Cpus_allowed_list:      0
      
         Here, the Cpus_allowed_list was originally "2" and has become
         "0-1,3" after cpu #2 is offlined.
      
         This "Cpus_allowed_list:      0" is incorrect.
      
      2) If the current task is a userspace task, the user may change its
         cpu-affinity during the CPU hot-unplugging.  This change can be
         overwritten when _cpu_down() changes the current task's affinity.
      
      
      Fix all this by not changing the current tasks's affinity.  Instead we
      create a kernel thread to do the work.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      0fdcbb46
  10. 28 Jul, 2009 1 commit
    • Oleg Nesterov's avatar
      sys_delete_module() can set MODULE_STATE_GOING after · dfdcb38a
      Oleg Nesterov authored
      search_binary_handler() does try_module_get().  In this case
      set_binfmt()->try_module_get() fails but since none of the callers
      check the returned error, the task will run with the wrong old
      ->binfmt.
      
      The proper fix should change all ->load_binary() methods, but we can
      rely on fact that the caller must hold a reference to binfmt->module
      and use __module_get() which never fails.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
      Cc: Roland McGrath <roland@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      dfdcb38a
  11. 22 Jul, 2009 2 commits
    • Neil Horman's avatar
      Allow core_pattern pipes to wait for user space to complete · 00c67933
      Neil Horman authored
      One of the things that user space processes like to do is look at metadata
      for a crashing process in their /proc/<pid> directory.  this is racy
      however, since do_coredump in the kernel doesn't wait for the user space
      process to complete before it reaps the crashing process.  This patch
      corrects that.  Allowing the kernel to wait for the user space process to
      complete before cleaning up the crashing process.  This is a bit tricky to
      do for a few reasons:
      
      1) The user space process isn't our child, so we can't sys_wait4 on it
      2) We need to close the pipe before waiting for the user process to complete,
      since the user process may rely on an EOF condition
      
      I've discussed several solutions with Oleg Nesterov off-list about this,
      and this is the one we've come up with.  We add ourselves as a pipe reader
      (to prevent premature cleanup of the pipe_inode_info), and remove
      ourselves as a writer (to provide an EOF condition to the writer in user
      space), then we iterate until the user space process exits (which we
      detect by pipe->readers == 1, hence the > 1 check in the loop).  When we
      exit the loop, we restore the proper reader/writer values, then we return
      and let filp_close in do_coredump clean up the pipe data properly.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Reported-by: default avatarEarl Chew <earl_chew@agilent.com>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      00c67933
    • Andrew Morton's avatar
      ERROR: code indent should use tabs where possible · cbee3c33
      Andrew Morton authored
      #115: FILE: fs/exec.c:1838:
      + ^I^Iif (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL,$
      
      ERROR: code indent should use tabs where possible
      #120: FILE: fs/exec.c:1842:
      + ^I^I^Igoto fail_dropcount;$
      
      WARNING: externs should be avoided in .c files
      #149: FILE: kernel/sysctl.c:80:
      +extern unsigned int core_pipe_limit;
      
      total: 2 errors, 1 warnings, 120 lines checked
      
      ./patches/exec-let-do_coredump-limit-the-number-of-concurrent-dumps-to-pipes-v9.patch has style problems, please review.  If any of these errors
      are false positives report them to the maintainer, see
      CHECKPATCH in MAINTAINERS.
      
      Please run checkpatch prior to sending patches
      
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      cbee3c33
  12. 24 Aug, 2009 1 commit
    • Neil Horman's avatar
      Introduce core pipe limiting sysctl. · d4a72aff
      Neil Horman authored
      Since we can dump cores to pipe, rather than directly to the filesystem,
      we create a condition in which a user can create a very high load on the
      system simply by running bad applications.
      
      If the pipe reader specified in core_pattern is poorly written, we can
      have lots of ourstandig resources and processes in the system.
      
      This sysctl introduces an ability to limit that resource consumption. 
      core_pipe_limit defines how many in-flight dumps may be run in parallel,
      dumps beyond this value are skipped and a note is made in the kernel log. 
      A special value of 0 in core_pipe_limit denotes unlimited core dumps may
      be handled (this is the default value).
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Reported-by: default avatarEarl Chew <earl_chew@agilent.com>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      d4a72aff
  13. 22 Jul, 2009 2 commits
    • Andrew Morton's avatar
      WARNING: suspect code indent for conditional statements (16, 25) · c717903f
      Andrew Morton authored
      #48: FILE: fs/exec.c:1796:
      +		if (core_limit == 0) {
      +			 /*
      
      WARNING: line over 80 characters
      #57: FILE: fs/exec.c:1805:
      +			  * but it runs as root, and can do lots of stupid things
      
      WARNING: line over 80 characters
      #58: FILE: fs/exec.c:1806:
      +			  * Note that we use task_tgid_vnr here to grab the pid of the
      
      WARNING: line over 80 characters
      #59: FILE: fs/exec.c:1807:
      +			  * process group leader.  That way we get the right pid if a thread
      
      total: 0 errors, 4 warnings, 59 lines checked
      
      ./patches/exec-make-do_coredump-more-resilient-to-recursive-crashes-v9.patch has style problems, please review.  If any of these errors
      are false positives report them to the maintainer, see
      CHECKPATCH in MAINTAINERS.
      
      Please run checkpatch prior to sending patches
      
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      c717903f
    • Neil Horman's avatar
      Change how we detect recursive dumps. · 45262796
      Neil Horman authored
      Currently we have a mechanism by which we try to compare pathnames of the
      crashing process to the core_pattern path.  This is broken for a dozen
      reasons, and just doesn't work in any sort of robust way.
      
      I'm replacing it with the use of a 0 RLIMIT_CORE value.  Since helper apps
      set RLIMIT_CORE to zero, we don't write out core files for any process
      with that particular limit set.  It the core_pattern is a pipe, any
      non-zero limit is translated to RLIM_INFINITY.
      
      This allows complete dumps to be captured, but prevents infinite recursion
      in the event that the core_pattern process itself crashes.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Reported-by: default avatarEarl Chew <earl_chew@agilent.com>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      45262796
  14. 24 Aug, 2009 5 commits
  15. 17 Aug, 2009 1 commit
    • Peter Zijlstra's avatar
      In order to direct the SIGIO signal to a particular thread of a · 8415576e
      Peter Zijlstra authored
      multi-threaded application we cannot, like suggested by the manpage, put a
      TID into the regular fcntl(F_SETOWN) call.  It will still be send to the
      whole process of which that thread is part.
      
      Since people do want to properly direct SIGIO we introduce F_SETOWN_EX.
      
      The need to direct SIGIO comes from self-monitoring profiling such as with
      perf-counters.  Perf-counters uses SIGIO to notify that new sample data is
      available.  If the signal is delivered to the same task that generated the
      new sample it can augment that data by inspecting the task's user-space
      state right after it returns from the kernel.  This is esp.  convenient
      for interpreted or virtual machine driven environments.
      
      Both F_SETOWN_EX and F_GETOWN_EX take a pointer to a struct f_owner_ex
      as argument:
      
      struct f_owner_ex {
      	int   type;
      	pid_t pid;
      };
      
      Where type is one of F_OWNER_TID, F_OWNER_PID or F_OWNER_GID.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
      Tested-by: default avatarstephane eranian <eranian@googlemail.com>
      Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      8415576e
  16. 04 Aug, 2009 2 commits
  17. 24 Aug, 2009 2 commits
  18. 13 Jul, 2009 1 commit
  19. 24 Aug, 2009 1 commit
    • Oleg Nesterov's avatar
      Thanks to Roland who pointed out de_thread() issues. · 5abc9a5a
      Oleg Nesterov authored
      Currently we add sub-threads to ->real_parent->children list.  This buys
      nothing but slows down do_wait().
      
      With this patch ->children contains only main threads (group leaders). 
      The only complication is that forget_original_parent() should iterate over
      sub-threads by hand, and de_thread() needs another list_replace() when it
      changes ->group_leader.
      
      Henceforth do_wait_thread() can never see task_detached() && !EXIT_DEAD
      tasks, we can remove this check (and we can unify do_wait_thread() and
      ptrace_do_wait()).
      
      This change can confuse the optimistic search in mm_update_next_owner(),
      but this is fixable and minor.
      
      Perhaps badness() and oom_kill_process() should be updated, but they
      should be fixed in any case.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Ratan Nalumasu <rnalumasu@gmail.com>
      Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      5abc9a5a
  20. 02 Sep, 2009 2 commits
  21. 13 Jul, 2009 1 commit
    • Oleg Nesterov's avatar
      Suggested by Roland. · c6c326b8
      Oleg Nesterov authored
      do_wait(__WNOTHREAD) can only succeed if the caller is either ptracer, or
      it is ->real_parent and the child is not traced. IOW, caller == p->parent
      otherwise we should not wake up.
      
      Change child_wait_callback() to check this. Ratan reports the workload with
      CPU load >99% caused by unnecessary wakeups, should be fixed by this patch.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Ratan Nalumasu <rnalumasu@gmail.com>
      Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      c6c326b8
  22. 24 Aug, 2009 1 commit
  23. 13 Jul, 2009 2 commits
  24. 24 Aug, 2009 1 commit
    • Oleg Nesterov's avatar
      The bug is old, it wasn't cause by recent changes. · 4ffaf27f
      Oleg Nesterov authored
      Test case:
      
      	static void *tfunc(void *arg)
      	{
      		int pid = (long)arg;
      
      		assert(ptrace(PTRACE_ATTACH, pid, NULL, NULL) == 0);
      		kill(pid, SIGKILL);
      
      		sleep(1);
      		return NULL;
      	}
      
      	int main(void)
      	{
      		pthread_t th;
      		long pid = fork();
      
      		if (!pid)
      			pause();
      
      		signal(SIGCHLD, SIG_IGN);
      		assert(pthread_create(&th, NULL, tfunc, (void*)pid) == 0);
      
      		int r = waitpid(-1, NULL, __WNOTHREAD);
      		printf("waitpid: %d %m\n", r);
      
      		return 0;
      	}
      
      Before the patch this program hangs, after this patch waitpid() correctly
      fails with errno == -ECHILD.
      
      The problem is, __ptrace_detach() reaps the EXIT_ZOMBIE tracee if its
      ->real_parent is our sub-thread and we ignore SIGCHLD.  But in this case
      we should wake up other threads which can sleep in do_wait().
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      4ffaf27f
  25. 04 Sep, 2009 1 commit
  26. 24 Aug, 2009 1 commit
  27. 14 Aug, 2009 1 commit
  28. 11 Aug, 2009 1 commit
    • Andrew Morton's avatar
      ERROR: spaces required around that '?' (ctx:VxW) · 81812a99
      Andrew Morton authored
      #50: FILE: mm/memcontrol.c:485:
      +	int val = (charge)? 1 : -1;
       	                  ^
      
      total: 1 errors, 0 warnings, 171 lines checked
      
      ./patches/memcg-improve-resource-counter-scalability.patch has style problems, please review.  If any of these errors
      are false positives report them to the maintainer, see
      CHECKPATCH in MAINTAINERS.
      
      Please run checkpatch prior to sending patches
      
      Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      81812a99