Commit 9e0a9616 authored by Zijun Hu's avatar Zijun Hu Committed by Zheng Qixing
Browse files

blk-cgroup: Fix class @block_class's subsystem refcount leakage 

stable inclusion
from stable-v6.6.78
commit 993121481b5a87829f1e8163f47158b72679f309
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPC90
CVE: CVE-2025-21745

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=993121481b5a87829f1e8163f47158b72679f309



------------------

commit d1248436cbef1f924c04255367ff4845ccd9025e upstream.

blkcg_fill_root_iostats() iterates over @block_class's devices by
class_dev_iter_(init|next)(), but does not end iterating with
class_dev_iter_exit(), so causes the class's subsystem refcount leakage.

Fix by ending the iterating with class_dev_iter_exit().

Fixes: ef45fe47 ("blk-cgroup: show global disk stats in root cgroup io.stat")
Reviewed-by: default avatarMichal Koutný <mkoutny@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarZijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20250105-class_fix-v6-2-3a2f1768d4d4@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZheng Qixing <zhengqixing@huawei.com>
parent 9d22d5b7

block/blk-cgroup.c

+1 −0
Original line number Diff line number Diff line
@@ -1139,6 +1139,7 @@ static void blkcg_fill_root_iostats(void) 
		blkg_iostat_set(&blkg->iostat.cur, &tmp);

		u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);

	}

	class_dev_iter_exit(&iter);

}



static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)