The patch titled
Subject: set_task_comm: kill the pointless memset() + wmb()
has been removed from the -mm tree. Its filename was
set_task_comm-kill-the-pointless-memset-wmb.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: set_task_comm: kill the pointless memset() + wmb()
set_task_comm() does memset() + wmb() before strlcpy(). This buys nothing
and to add to the confusion, the comment is wrong.
- We do not need memset() to be "safe from non-terminating string
reads", the final char is always zero and we never change it.
- wmb() is paired with nothing, it cannot prevent from printing
the mixture of the old/new data unless the reader takes the lock.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: John Stultz <johnstul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 10 ----------
1 file changed, 10 deletions(-)
diff -puN fs/exec.c~set_task_comm-kill-the-pointless-memset-wmb fs/exec.c
--- a/fs/exec.c~set_task_comm-kill-the-pointless-memset-wmb
+++ a/fs/exec.c
@@ -1027,17 +1027,7 @@ EXPORT_SYMBOL_GPL(get_task_comm);
void set_task_comm(struct task_struct *tsk, char *buf)
{
task_lock(tsk);
-
trace_task_rename(tsk, buf);
-
- /*
- * Threads may access current->comm without holding
- * the task lock, so write the string carefully.
- * Readers without a lock may see incomplete new
- * names but are safe from non-terminating string reads.
- */
- memset(tsk->comm, 0, TASK_COMM_LEN);
- wmb();
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
task_unlock(tsk);
perf_event_comm(tsk);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
posix_cpu_timer-consolidate-expiry-time-type.patch
posix_cpu_timers-consolidate-timer-list-cleanups.patch
posix_cpu_timers-consolidate-expired-timers-check.patch
posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch
posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
