From: Phong Tran <tranmanphong@gmail.com>
To: tytso@mit.edu, adilger.kernel@dilger.ca, paulmck@kernel.org,
joel@joelfernandes.org
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
rcu@vger.kernel.org, Phong Tran <tranmanphong@gmail.com>
Subject: [PATCH] ext4: use rcu API in debug_print_tree
Date: Sun, 1 Dec 2019 10:51:07 +0700 [thread overview]
Message-ID: <20191201035107.24355-1-tranmanphong@gmail.com> (raw)
struct ext4_sb_info.system_blks was marked __rcu.
But access the pointer without using RCU lock and dereference.
Sparse warning with __rcu notation:
block_validity.c:139:29: warning: incorrect type in argument 1 (different address spaces)
block_validity.c:139:29: expected struct rb_root const *
block_validity.c:139:29: got struct rb_root [noderef] <asn:4> *
Signed-off-by: Phong Tran <tranmanphong@gmail.com>
---
fs/ext4/block_validity.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index d4d4fdfac1a6..1ee04e76bbe0 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -133,10 +133,13 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
{
struct rb_node *node;
struct ext4_system_zone *entry;
+ struct ext4_system_blocks *system_blks;
int first = 1;
printk(KERN_INFO "System zones: ");
- node = rb_first(&sbi->system_blks->root);
+ rcu_read_lock();
+ system_blks = rcu_dereference(sbi->system_blks);
+ node = rb_first(&system_blks->root);
while (node) {
entry = rb_entry(node, struct ext4_system_zone, node);
printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",
@@ -144,6 +147,7 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
first = 0;
node = rb_next(node);
}
+ rcu_read_unlock();
printk(KERN_CONT "\n");
}
--
2.20.1
next reply other threads:[~2019-12-01 3:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-01 3:51 Phong Tran [this message]
2019-12-13 11:35 ` [PATCH] ext4: use rcu API in debug_print_tree Jan Kara
2019-12-13 15:33 ` [PATCH V2] " Phong Tran
2019-12-13 18:11 ` Joel Fernandes
2019-12-13 19:49 ` Jan Kara
2019-12-13 23:19 ` Joel Fernandes
2019-12-16 2:41 ` Theodore Y. Ts'o
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