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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ming Lei <ming.lei@redhat.com>, Tejun Heo <tj@kernel.org>,
	Bruno Goncalves <bgoncalv@redhat.com>,
	Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
	linux-block@vger.kernel.org
Subject: [PATCH AUTOSEL 5.13 10/12] blk-iocost: fix lockdep warning on blkcg->lock
Date: Mon, 16 Aug 2021 20:35:34 -0400	[thread overview]
Message-ID: <20210817003536.83063-10-sashal@kernel.org> (raw)
In-Reply-To: <20210817003536.83063-1-sashal@kernel.org>

From: Ming Lei <ming.lei@redhat.com>

[ Upstream commit 11431e26c9c43fa26f6b33ee1a90989f57b86024 ]

blkcg->lock depends on q->queue_lock which may depend on another driver
lock required in irq context, one example is dm-thin:

	Chain exists of:
	  &pool->lock#3 --> &q->queue_lock --> &blkcg->lock

	 Possible interrupt unsafe locking scenario:

	       CPU0                    CPU1
	       ----                    ----
	  lock(&blkcg->lock);
	                               local_irq_disable();
	                               lock(&pool->lock#3);
	                               lock(&q->queue_lock);
	  <Interrupt>
	    lock(&pool->lock#3);

Fix the issue by using spin_lock_irq(&blkcg->lock) in ioc_weight_write().

Cc: Tejun Heo <tj@kernel.org>
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Link: https://lore.kernel.org/linux-block/CA+QYu4rzz6079ighEanS3Qq_Dmnczcf45ZoJoHKVLVATTo1e4Q@mail.gmail.com/T/#u
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210803070608.1766400-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 block/blk-iocost.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 5fac3757e6e0..0e56557cacf2 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -3061,19 +3061,19 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf,
 		if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX)
 			return -EINVAL;
 
-		spin_lock(&blkcg->lock);
+		spin_lock_irq(&blkcg->lock);
 		iocc->dfl_weight = v * WEIGHT_ONE;
 		hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
 			struct ioc_gq *iocg = blkg_to_iocg(blkg);
 
 			if (iocg) {
-				spin_lock_irq(&iocg->ioc->lock);
+				spin_lock(&iocg->ioc->lock);
 				ioc_now(iocg->ioc, &now);
 				weight_updated(iocg, &now);
-				spin_unlock_irq(&iocg->ioc->lock);
+				spin_unlock(&iocg->ioc->lock);
 			}
 		}
-		spin_unlock(&blkcg->lock);
+		spin_unlock_irq(&blkcg->lock);
 
 		return nbytes;
 	}
-- 
2.30.2


  parent reply	other threads:[~2021-08-17  0:36 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17  0:35 [PATCH AUTOSEL 5.13 01/12] ASoC: rt5682: Adjust headset volume button threshold Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 02/12] ASoC: component: Remove misplaced prefix handling in pin control functions Sasha Levin
2021-08-30 12:49   ` Pavel Machek
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 03/12] ASoC: wm_adsp: Let soc_cleanup_component_debugfs remove debugfs Sasha Levin
2021-08-18 13:15   ` Charles Keepax
2021-08-19 13:26     ` Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 04/12] platform/x86: Add and use a dual_accel_detect() helper Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 05/12] ARC: Fix CONFIG_STACKDEPOT Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 06/12] netfilter: ipset: Limit the maximal range of consecutive elements to add/delete Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 07/12] netfilter: conntrack: collect all entries in one cycle Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 08/12] once: Fix panic when module unload Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 09/12] io_uring: rsrc ref lock needs to be IRQ safe Sasha Levin
2021-08-17  0:35 ` Sasha Levin [this message]
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 11/12] ovl: fix uninitialized pointer read in ovl_lookup_real_one() Sasha Levin
2021-08-17  0:35 ` [PATCH AUTOSEL 5.13 12/12] net: mscc: Fix non-GPL export of regmap APIs Sasha Levin

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