Patch "blk-cgroup: fix rcu lockdep warning in blkg_lookup()" has been added to the 6.6-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    blk-cgroup: fix rcu lockdep warning in blkg_lookup()

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     blk-cgroup-fix-rcu-lockdep-warning-in-blkg_lookup.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 43f1d7adc8c5130b146934aca5907ffc0f1feda8
Author: Ming Lei <ming.lei@xxxxxxxxxx>
Date:   Tue Dec 19 09:28:33 2023 +0800

    blk-cgroup: fix rcu lockdep warning in blkg_lookup()
    
    [ Upstream commit 393cd8ffd832f23eec3a105553eff622e8198918 ]
    
    blkg_lookup() is called with either queue_lock or rcu read lock, so
    use rcu_dereference_check(lockdep_is_held(&q->queue_lock)) for
    retrieving 'blkg', which way models the check exactly for covering
    queue lock or rcu read lock.
    
    Fix lockdep warning of "block/blk-cgroup.h:254 suspicious rcu_dereference_check() usage!"
    from blkg_lookup().
    
    Tested-by: Changhui Zhong <czhong@xxxxxxxxxx>
    Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
    Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
    Fixes: 83462a6c971c ("blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish()")
    Acked-by: Tejun Heo <tj@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20231219012833.2129540-1-ming.lei@xxxxxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index fd482439afbc..b927a4a0ad03 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -252,7 +252,8 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
 	if (blkcg == &blkcg_root)
 		return q->root_blkg;
 
-	blkg = rcu_dereference(blkcg->blkg_hint);
+	blkg = rcu_dereference_check(blkcg->blkg_hint,
+			lockdep_is_held(&q->queue_lock));
 	if (blkg && blkg->q == q)
 		return blkg;
 




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux