diff options
author | Paul E. McKenney <paulmck@kernel.org> | 2021-05-25 10:12:45 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-31 08:16:11 +0200 |
commit | 55ddab2bfd7035347765e62748fd1e30cb3528d6 (patch) | |
tree | cd6bb741a54e7740c23129c32508998afcb40897 /kernel | |
parent | 4d972881f8d8e80e0320169e681284785cfe51e2 (diff) |
rcu-tasks: Don't delete holdouts within trc_inspect_reader()
[ Upstream commit 1d10bf55d85d34eb73dd8263635f43fd72135d2d ]
As Yanfei pointed out, although invoking trc_del_holdout() is safe
from the viewpoint of the integrity of the holdout list itself,
the put_task_struct() invoked by trc_del_holdout() can result in
use-after-free errors due to later accesses to this task_struct structure
by the RCU Tasks Trace grace-period kthread.
This commit therefore removes this call to trc_del_holdout() from
trc_inspect_reader() in favor of the grace-period thread's existing call
to trc_del_holdout(), thus eliminating that particular class of
use-after-free errors.
Reported-by: "Xu, Yanfei" <yanfei.xu@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/rcu/tasks.h | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 73bbe792fe1e..208acb286ec2 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -879,10 +879,9 @@ static bool trc_inspect_reader(struct task_struct *t, void *arg) in_qs = likely(!t->trc_reader_nesting); } - // Mark as checked. Because this is called from the grace-period - // kthread, also remove the task from the holdout list. + // Mark as checked so that the grace-period kthread will + // remove it from the holdout list. t->trc_reader_checked = true; - trc_del_holdout(t); if (in_qs) return true; // Already in quiescent state, done!!! |