[PATCH 1/4] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rost...@goodmis.org>

If memory reclaim happens, it can reclaim file system pages. The file
system pages from eventfs may take the eventfs_mutex on reclaim. This
means that allocation while holding the eventfs_mutex must not call into
filesystem reclaim. A lockdep splat uncovered this.

Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode")
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Mark Rutland <mark.rutl...@arm.com>
Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
 fs/tracefs/event_inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 3eb6c622a74d..56d192f0ead8 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -95,7 +95,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct 
dentry *dentry,
        if (!(dentry->d_inode->i_mode & S_IFDIR)) {
                if (!ei->entry_attrs) {
                        ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * 
ei->nr_entries,
-                                                 GFP_KERNEL);
+                                                 GFP_NOFS);
                        if (!ei->entry_attrs) {
                                ret = -ENOMEM;
                                goto out;
@@ -627,7 +627,7 @@ static int add_dentries(struct dentry ***dentries, struct 
dentry *d, int cnt)
 {
        struct dentry **tmp;
 
-       tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
+       tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS);
        if (!tmp)
                return -1;
        tmp[cnt] = d;
-- 
2.42.0