From: "Steven Rostedt (Google)" rostedt@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.
Link: https://lkml.kernel.org/r/20231121231112.373501894@goodmis.org
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode") Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode") Reported-by: Mark Rutland mark.rutland@arm.com Reviewed-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org (cherry picked from commit 4763d635c907baed212664dc579dde1663bb2676) --- 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;