[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1243628537.6645.106.camel@laptop>
Date: Fri, 29 May 2009 22:22:17 +0200
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Ingo Molnar <mingo@...e.hu>, Mike Galbraith <efault@....de>,
Paul Mackerras <paulus@...ba.org>,
Thomas Gleixner <tglx@...utronix.de>,
Steven Rostedt <rostedt@...dmis.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH tip 1/1] perf_counter tools: Add locking to perf top
On Fri, 2009-05-29 at 17:03 -0300, Arnaldo Carvalho de Melo wrote:
> /* Sort the active symbols */
> - list_for_each_entry_safe(syme, n, &active_symbols, node) {
> - if (syme->count[0] != 0) {
> + pthread_mutex_lock(&active_symbols_lock);
> + syme = list_entry(active_symbols.next, struct sym_entry, node);
> + pthread_mutex_unlock(&active_symbols_lock);
> +
> + list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
> + syme->snap_count = syme->count[0];
> + if (syme->snap_count != 0) {
> + syme->weight = sym_weight(syme);
That looks wrong, you basically do a fancy cast while holding the lock,
then you overwrite the variable doing a list iteration without holding
the lock.
If list_add and list_del are under a lock, the iteration should be too.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists