From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 01/21] srcu: Tighten cleanup_srcu_struct() GP checks
Date: Mon, 18 Apr 2022 17:03:02 -0700 [thread overview]
Message-ID: <20220419000322.3948903-1-paulmck@kernel.org> (raw)
In-Reply-To: <20220419000315.GA3948789@paulmck-ThinkPad-P17-Gen-1>
Currently, cleanup_srcu_struct() checks for a grace period in progress,
but it does not check for a grace period that has not yet started but
which might start at any time. Such a situation could result in a
use-after-free bug, so this commit adds a check for a grace period that
is needed but not yet started to cleanup_srcu_struct().
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/srcutree.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 6833d8887181..d30e4db04506 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -382,9 +382,11 @@ void cleanup_srcu_struct(struct srcu_struct *ssp)
return; /* Forgot srcu_barrier(), so just leak it! */
}
if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
+ WARN_ON(rcu_seq_current(&ssp->srcu_gp_seq) != ssp->srcu_gp_seq_needed) ||
WARN_ON(srcu_readers_active(ssp))) {
- pr_info("%s: Active srcu_struct %p state: %d\n",
- __func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)));
+ pr_info("%s: Active srcu_struct %p read state: %d gp state: %lu/%lu\n",
+ __func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)),
+ rcu_seq_current(&ssp->srcu_gp_seq), ssp->srcu_gp_seq_needed);
return; /* Caller forgot to stop doing call_srcu()? */
}
free_percpu(ssp->sda);
--
2.31.1.189.g2e36527f23
next prev parent reply other threads:[~2022-04-19 0:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 0:03 [PATCH rcu 0/21] SRCU updates for v5.19 Paul E. McKenney
2022-04-19 0:03 ` Paul E. McKenney [this message]
2022-04-19 0:03 ` [PATCH rcu 02/21] srcu: Fix s/is/if/ typo in srcu_node comment Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 03/21] srcu: Make srcu_funnel_gp_start() cache ->mynode in snp_leaf Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 04/21] srcu: Make Tree SRCU able to operate without snp_node array Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 05/21] srcu: Dynamically allocate srcu_node array Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 06/21] srcu: Add size-state transitioning code Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 07/21] srcu: Make rcutorture dump the SRCU size state Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 08/21] srcu: Compute snp_seq earlier in srcu_funnel_gp_start() Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 09/21] srcu: Use invalid initial value for srcu_node GP sequence numbers Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 10/21] srcu: Ensure snp nodes tree is fully initialized before traversal Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 11/21] srcu: Add boot-time control over srcu_node array allocation Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 12/21] srcu: Use export for srcu_struct defined by DEFINE_STATIC_SRCU() Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 13/21] srcu: Avoid NULL dereference in srcu_torture_stats_print() Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 14/21] srcu: Prevent cleanup_srcu_struct() from freeing non-dynamic ->sda Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 15/21] srcu: Explain srcu_funnel_gp_start() call to list_add() is safe Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 16/21] srcu: Create concurrency-safe helper for initiating size transition Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 17/21] srcu: Add contention-triggered addition of srcu_node tree Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 18/21] srcu: Automatically determine size-transition strategy at boot Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 19/21] srcu: Add contention check to call_srcu() srcu_data ->lock acquisition Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 20/21] srcu: Prevent expedited GPs and blocking readers from consuming CPU Paul E. McKenney
2022-04-19 0:03 ` [PATCH rcu 21/21] srcu: Drop needless initialization of sdp in srcu_gp_start() Paul E. McKenney
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