linux-kernel - [tip: core/rcu] srcu: Take early exit on memory-allocation failure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <160788605872.3364.276499462904083916.tip-bot2@tip-bot2>
Date:   Sun, 13 Dec 2020 19:00:58 -0000
From:   "tip-bot2 for Paul E. McKenney" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Alexey Kardashevskiy <aik@...abs.ru>,
        "Paul E. McKenney" <paulmck@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: core/rcu] srcu: Take early exit on memory-allocation failure

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     50edb988534c621a56ca103c0c16ac59e7399f01
Gitweb:        https://git.kernel.org/tip/50edb988534c621a56ca103c0c16ac59e7399f01
Author:        Paul E. McKenney <paulmck@...nel.org>
AuthorDate:    Thu, 10 Sep 2020 11:54:42 -07:00
Committer:     Paul E. McKenney <paulmck@...nel.org>
CommitterDate: Thu, 19 Nov 2020 19:37:17 -08:00

srcu: Take early exit on memory-allocation failure

It turns out that init_srcu_struct() can be invoked from usermode tasks,
and that fatal signals received by these tasks can cause memory-allocation
failures.  These failures are not handled well by init_srcu_struct(),
so much so that NULL pointer dereferences can result.  This commit
therefore causes init_srcu_struct() to take an early exit upon detection
of memory-allocation failure.

Link: https://lore.kernel.org/lkml/20200908144306.33355-1-aik@ozlabs.ru/
Reported-by: Alexey Kardashevskiy <aik@...abs.ru>
Tested-by: Alexey Kardashevskiy <aik@...abs.ru>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 kernel/rcu/srcutree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index c13348e..6f7880a 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -177,11 +177,13 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 	INIT_DELAYED_WORK(&ssp->work, process_srcu);
 	if (!is_static)
 		ssp->sda = alloc_percpu(struct srcu_data);
+	if (!ssp->sda)
+		return -ENOMEM;
 	init_srcu_struct_nodes(ssp, is_static);
 	ssp->srcu_gp_seq_needed_exp = 0;
 	ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
 	smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
-	return ssp->sda ? 0 : -ENOMEM;
+	return 0;
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC