Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4d1b1ef0 authored by Karthikeyan Ramasubramanian's avatar Karthikeyan Ramasubramanian Committed by Gerrit - the friendly Code Review server
Browse files

soc: qcom: glink_debugfs: Defer removing debugfs entries 



Removing debugfs entries waits for synchronization with global
debugfs_srcu. This leads to a deadlock if a debugfs entry is removed
while reading from another debugfs entry.

Defer removing the debugfs entries to avoid any deadlock.

CRs-Fixed: 1079350
Change-Id: I4404f77fec93ba16ecf60699b0d9e46cd9488739
Signed-off-by: default avatarKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
parent 974132c3

drivers/soc/qcom/glink_debugfs.c

+20 −5
Original line number Diff line number Diff line
@@ -64,6 +64,8 @@ struct glink_dbgfs_dent { 
	struct dentry *self;

	spinlock_t file_list_lock_lhb0;

	struct list_head file_list;

	bool rm_debugfs;

	struct work_struct rm_work;

};



static struct dentry *dent;
@@ -91,6 +93,7 @@ static const struct file_operations debug_ops = { 
	.llseek = seq_lseek,

};

#endif

static void glink_dfs_dent_rm_worker(struct work_struct *work);



/**

 * glink_get_ss_enum_string() - get the name of the subsystem based on enum
@@ -568,6 +571,8 @@ void glink_dfs_update_list(struct dentry *curr_dent, struct dentry *parent, 
				curr, strlen(curr) + 1);

			strlcpy(dbgfs_dent_s->par_name, par_dir,

					strlen(par_dir) + 1);

			INIT_WORK(&dbgfs_dent_s->rm_work,

				  glink_dfs_dent_rm_worker);

			mutex_lock(&dent_list_lock_lha0);

			list_add_tail(&dbgfs_dent_s->list_node, &dent_list);

			mutex_unlock(&dent_list_lock_lha0);
@@ -606,8 +611,21 @@ void glink_remove_dfs_entry(struct glink_dbgfs_dent *entry) 
		spin_unlock_irqrestore(&entry->file_list_lock_lhb0, flags);

	}

	list_del(&entry->list_node);

	schedule_work(&entry->rm_work);

}



/**

 * glink_dfs_dent_rm_worker() - Remove the debugfs entry recursively

 * @work:	Deferred work whose entry needs to be removed.

 */

static void glink_dfs_dent_rm_worker(struct work_struct *work)

{

	struct glink_dbgfs_dent *entry =

		container_of(work, struct glink_dbgfs_dent, rm_work);



	if (entry->rm_debugfs)

		debugfs_remove_recursive(entry->self);

	kfree(entry);

	entry = NULL;

}



/**
@@ -622,7 +640,6 @@ void glink_debugfs_remove_recur(struct glink_dbgfs *rm_dfs) 
	const char *c_dir_name;

	const char *p_dir_name;

	struct glink_dbgfs_dent *entry, *entry_temp;

	struct dentry *par_dent = NULL;



	if (rm_dfs == NULL)

		return;
@@ -636,13 +653,11 @@ void glink_debugfs_remove_recur(struct glink_dbgfs *rm_dfs) 
			glink_remove_dfs_entry(entry);

		} else if (!strcmp(entry->self_name, c_dir_name)

				&& !strcmp(entry->par_name, p_dir_name)) {

			par_dent = entry->self;

			entry->rm_debugfs = true;

			glink_remove_dfs_entry(entry);

		}

	}

	mutex_unlock(&dent_list_lock_lha0);

	if (par_dent != NULL)

		debugfs_remove_recursive(par_dent);

}

EXPORT_SYMBOL(glink_debugfs_remove_recur);