LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, "Xu, Yanfei" <yanfei.xu@windriver.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 11/24] rcu-tasks: Dont delete holdouts within trc_inspect_reader()
Date: Thu, 29 Jul 2021 15:54:31 +0200	[thread overview]
Message-ID: <20210729135137.616116362@linuxfoundation.org> (raw)
In-Reply-To: <20210729135137.267680390@linuxfoundation.org>

From: Paul E. McKenney <paulmck@kernel.org>

[ 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>
---
 kernel/rcu/tasks.h | 5 ++---
 1 file 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!!!
-- 
2.30.2




  parent reply	other threads:[~2021-07-29 13:58 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 13:54 [PATCH 5.10 00/24] 5.10.55-rc1 review Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 01/24] tools: Allow proper CC/CXX/... override with LLVM=1 in Makefile.include Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 02/24] [PATCH] io_uring: fix link timeout refs Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 03/24] KVM: x86: determine if an exception has an error code only when injecting it Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 04/24] af_unix: fix garbage collect vs MSG_PEEK Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 05/24] workqueue: fix UAF in pwq_unbound_release_workfn() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 06/24] cgroup1: fix leaked context root causing sporadic NULL deref in LTP Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 07/24] net/802/mrp: fix memleak in mrp_request_join() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 08/24] net/802/garp: fix memleak in garp_request_join() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 09/24] net: annotate data race around sk_ll_usec Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 10/24] sctp: move 198 addresses from unusable to private scope Greg Kroah-Hartman
2021-07-29 13:54 ` Greg Kroah-Hartman [this message]
2021-07-29 13:54 ` [PATCH 5.10 12/24] rcu-tasks: Dont delete holdouts within trc_wait_for_one_reader() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 13/24] ipv6: allocate enough headroom in ip6_finish_output2() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 14/24] drm/ttm: add a check against null pointer dereference Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 15/24] hfs: add missing clean-up in hfs_fill_super Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 16/24] hfs: fix high memory mapping in hfs_bnode_read Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 17/24] hfs: add lock nesting notation to hfs_find_init Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 18/24] firmware: arm_scmi: Fix possible scmi_linux_errmap buffer overflow Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 19/24] firmware: arm_scmi: Fix range check for the maximum number of pending messages Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 20/24] cifs: fix the out of range assignment to bit fields in parse_server_interfaces Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 21/24] iomap: remove the length variable in iomap_seek_data Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 22/24] iomap: remove the length variable in iomap_seek_hole Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 23/24] ARM: dts: versatile: Fix up interrupt controller node names Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 5.10 24/24] ipv6: ip6_finish_output2: set sk into newly allocated nskb Greg Kroah-Hartman
2021-07-29 19:47 ` [PATCH 5.10 00/24] 5.10.55-rc1 review Pavel Machek
2021-07-29 22:53 ` Shuah Khan
2021-07-30  4:58   ` Greg Kroah-Hartman
2021-07-29 23:36 ` Florian Fainelli
2021-07-30  2:40 ` Shuah Khan
2021-07-30  6:23 ` Naresh Kamboju
2021-07-30 10:12 ` Sudip Mukherjee
2021-07-31  4:43 ` Guenter Roeck
2021-07-31  7:51 ` Fox Chen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210729135137.616116362@linuxfoundation.org \
    --to=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=paulmck@kernel.org \
    --cc=sashal@kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=yanfei.xu@windriver.com \
    --subject='Re: [PATCH 5.10 11/24] rcu-tasks: Dont delete holdouts within trc_inspect_reader()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).