Hi Andrew, On Thursday 10 May 2007 07:20, you wrote: > On Wed, 9 May 2007 14:13:27 +0530 Sripathi Kodi <[EMAIL PROTECTED]> wrote:
<snip old patch> > Your changelogs aren't vey logical. The context for this change is off in > > a different patch. I reproduce it here: > > I am trying to fix the BUG I mentioned here: > > http://lkml.org/lkml/2007/04/20/41. I noticed that an elegant way to > > solve this problem is to have a write_trylock_irqsave helper function. > > Since we don't have this now, the code in ptrace_attach implements it > > using local_irq_disable and write_trylock. I wish to add > > write_trylock_irqsave to mainline kernel and then fix the -rt specific > > problem using this. > > I can't imagine why -rt's write_unlock_irq() doesn't do local_irq_enable(). > > I have no problem adding write_trylock_irqsave() - it fills a gap in the > API. > > Once we have write_trylock_irqsave() it makes sense to use it here. > > One the downside, we added a few bytes to the SMP kernel, which I guess we > can live with. > > Whether this change is desired in -rt I don't know. Ingo? > > I don't think the initialisation of `flags' there was needed? I removed the initialization of 'flags' in the following patch. Would you like to drop the old one and pick up this? Signed-off-by: Sripathi Kodi <[EMAIL PROTECTED]> diff -uprN linux-2.6.21.1_org/kernel/ptrace.c linux-2.6.21.1/kernel/ptrace.c --- linux-2.6.21.1_org/kernel/ptrace.c 2007-05-09 13:18:39.000000000 +0530 +++ linux-2.6.21.1/kernel/ptrace.c 2007-05-10 17:40:51.000000000 +0530 @@ -160,6 +160,7 @@ int ptrace_may_attach(struct task_struct int ptrace_attach(struct task_struct *task) { int retval; + unsigned long flags; retval = -EPERM; if (task->pid <= 1) @@ -178,9 +179,7 @@ repeat: * cpu's that may have task_lock). */ task_lock(task); - local_irq_disable(); - if (!write_trylock(&tasklist_lock)) { - local_irq_enable(); + if (!write_trylock_irqsave(&tasklist_lock, flags)) { task_unlock(task); do { cpu_relax(); @@ -208,7 +207,7 @@ repeat: force_sig_specific(SIGSTOP, task); bad: - write_unlock_irq(&tasklist_lock); + write_unlock_irqrestore(&tasklist_lock, flags); task_unlock(task); out: return retval; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
