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  1. 28 10月, 2005 11 次提交
  3. 27 10月, 2005 12 次提交
  5. 26 10月, 2005 7 次提交
  7. 25 10月, 2005 5 次提交
  9. 24 10月, 2005 5 次提交
    • M
      [PATCH] uml: fix compile failure for TT mode · 10ded949
      由 Miklos Szeredi 提交于 
      Without this patch, uml compile fails with:

  LD      .tmp_vmlinux1
arch/um/kernel/built-in.o: In function `config_gdb_cb':
arch/um/kernel/tt/gdb.c:129: undefined reference to `TASK_EXTERN_PID'

Tested on i386, but fix needed on x86_64 too AFAICS.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      10ded949
    • O
      [PATCH] posix-timers: fix posix_cpu_timer_set() vs run_posix_cpu_timers() race · a69ac4a7
      由 Oleg Nesterov 提交于 
      This might be harmless, but looks like a race from code inspection (I
was unable to trigger it).  I must admit, I don't understand why we
can't return TIMER_RETRY after 'spin_unlock(&p->sighand->siglock)'
without doing bump_cpu_timer(), but this is what original code does.

posix_cpu_timer_set:

	read_lock(&tasklist_lock);

	spin_lock(&p->sighand->siglock);
	list_del_init(&timer->it.cpu.entry);
	spin_unlock(&p->sighand->siglock);

We are probaly deleting the timer from run_posix_cpu_timers's 'firing'
local list_head while run_posix_cpu_timers() does list_for_each_safe.

Various bad things can happen, for example we can just delete this timer
so that list_for_each() will not notice it and run_posix_cpu_timers()
will not reset '->firing' flag. In that case,

	....

	if (timer->it.cpu.firing) {
		read_unlock(&tasklist_lock);
		timer->it.cpu.firing = -1;
		return TIMER_RETRY;
	}

sys_timer_settime() goes to 'retry:', calls posix_cpu_timer_set() again,
it returns TIMER_RETRY ...
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      a69ac4a7
    • O
      [PATCH] posix-timers: exit path cleanup · ca531a0a
      由 Oleg Nesterov 提交于 
      No need to rebalance when task exited
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ca531a0a
    • O
      [PATCH] posix-timers: remove false BUG_ON() from run_posix_cpu_timers() · 3de463c7
      由 Oleg Nesterov 提交于 
      do_exit() clears ->it_##clock##_expires, but nothing prevents
another cpu to attach the timer to exiting process after that.

After exit_notify() does 'write_unlock_irq(&tasklist_lock)' and
before do_exit() calls 'schedule() local timer interrupt can find
tsk->exit_state != 0. If that state was EXIT_DEAD (or another cpu
does sys_wait4) interrupted task has ->signal == NULL.

At this moment exiting task has no pending cpu timers, they were cleaned
up in __exit_signal()->posix_cpu_timers_exit{,_group}(), so we can just
return from irq.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3de463c7
    • O
      [PATCH] posix-timers: fix cleanup_timers() and run_posix_cpu_timers() races · 108150ea
      由 Oleg Nesterov 提交于 
      1. cleanup_timers() sets timer->task = NULL under tasklist + ->sighand locks.
   That means that this code in posix_cpu_timer_del() and posix_cpu_timer_set()

   		lock_timer(timer);
		if (timer->task == NULL)
			return;
		read_lock(tasklist);
		put_task_struct(timer->task)

   is racy. With this patch timer->task modified and accounted only under
   timer->it_lock. Sadly, this means that dead task_struct won't be freed
   until timer deleted or armed.

2. run_posix_cpu_timers() collects expired timers into local list under
   tasklist + ->sighand again. That means that posix_cpu_timer_del()
   should check timer->it.cpu.firing under these locks too.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      108150ea