* [PATCH AUTOSEL 5.8 15/29] blk-cgroup: Fix memleak on error path
[not found] <20201103011928.183145-1-sashal@kernel.org>
@ 2020-11-03 1:19 ` Sasha Levin
2020-11-03 1:19 ` [PATCH AUTOSEL 5.8 16/29] blk-cgroup: Pre-allocate tree node on blkg_conf_prep Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-11-03 1:19 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Gabriel Krisman Bertazi, Tejun Heo, Jens Axboe, Sasha Levin,
cgroups, linux-block
From: Gabriel Krisman Bertazi <krisman@collabora.com>
[ Upstream commit 52abfcbd57eefdd54737fc8c2dc79d8f46d4a3e5 ]
If new_blkg allocation raced with blk_policy change and
blkg_lookup_check fails, new_blkg is leaked.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-cgroup.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6e8f5e60b0982..67619f4e24907 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -682,6 +682,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
blkg = blkg_lookup_check(pos, pol, q);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
+ blkg_free(new_blkg);
goto fail_unlock;
}
--
2.27.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH AUTOSEL 5.8 16/29] blk-cgroup: Pre-allocate tree node on blkg_conf_prep
[not found] <20201103011928.183145-1-sashal@kernel.org>
2020-11-03 1:19 ` [PATCH AUTOSEL 5.8 15/29] blk-cgroup: Fix memleak on error path Sasha Levin
@ 2020-11-03 1:19 ` Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-11-03 1:19 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Gabriel Krisman Bertazi, Tejun Heo, Jens Axboe, Sasha Levin,
cgroups, linux-block
From: Gabriel Krisman Bertazi <krisman@collabora.com>
[ Upstream commit f255c19b3ab46d3cad3b1b2e1036f4c926cb1d0c ]
Similarly to commit 457e490f2b741 ("blkcg: allocate struct blkcg_gq
outside request queue spinlock"), blkg_create can also trigger
occasional -ENOMEM failures at the radix insertion because any
allocation inside blkg_create has to be non-blocking, making it more
likely to fail. This causes trouble for userspace tools trying to
configure io weights who need to deal with this condition.
This patch reduces the occurrence of -ENOMEMs on this path by preloading
the radix tree element on a GFP_KERNEL context, such that we guarantee
the later non-blocking insertion won't fail.
A similar solution exists in blkcg_init_queue for the same situation.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-cgroup.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 67619f4e24907..1cd0574b83bb2 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -676,6 +676,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
goto fail;
}
+ if (radix_tree_preload(GFP_KERNEL)) {
+ blkg_free(new_blkg);
+ ret = -ENOMEM;
+ goto fail;
+ }
+
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
@@ -683,7 +689,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
blkg_free(new_blkg);
- goto fail_unlock;
+ goto fail_preloaded;
}
if (blkg) {
@@ -692,10 +698,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
blkg = blkg_create(pos, q, new_blkg);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
- goto fail_unlock;
+ goto fail_preloaded;
}
}
+ radix_tree_preload_end();
+
if (pos == blkcg)
goto success;
}
@@ -705,6 +713,8 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
ctx->body = input;
return 0;
+fail_preloaded:
+ radix_tree_preload_end();
fail_unlock:
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
--
2.27.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2020-11-03 1:19 ` [PATCH AUTOSEL 5.8 15/29] blk-cgroup: Fix memleak on error path Sasha Levin
2020-11-03 1:19 ` [PATCH AUTOSEL 5.8 16/29] blk-cgroup: Pre-allocate tree node on blkg_conf_prep Sasha Levin
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