Commit 69000d82 authored Dec 13, 2019 by Phong Tran Committed by Theodore Ts'o Dec 15, 2019

ext4: use RCU API in debug_print_tree

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> *

Link: https://lore.kernel.org/r/20191213153306.30744-1-tranmanphong@gmail.com


Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent 9803387c

fs/ext4/block_validity.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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");
		}

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