From: Mathias Krause minipli@grsecurity.net
Commit 77a06c33a22d ("eventfs: Test for ei->is_freed when accessing ei->dentry") added another check, testing if the parent was freed after we released the mutex. If so, the function returns NULL. However, all callers expect it to either return a valid pointer or an error pointer, at least since commit 5264a2f4bb3b ("tracing: Fix a NULL vs IS_ERR() bug in event_subsystem_dir()"). Returning NULL will therefore fail the error condition check in the caller.
Fix this by substituting the NULL return value with a fitting error pointer.
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: stable@vger.kernel.org Fixes: 77a06c33a22d ("eventfs: Test for ei->is_freed when accessing ei->dentry") Link: https://lore.kernel.org/20240723122522.2724-1-minipli@grsecurity.net Reviewed-by: Dan Carpenter dan.carpenter@linaro.org Reviewed-by: Ajay Kaher ajay.kaher@broadcom.com Signed-off-by: Mathias Krause minipli@grsecurity.net Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- fs/tracefs/event_inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 5d88c184f0fc..a9c28a1d5dc8 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -736,7 +736,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode /* Was the parent freed? */ if (list_empty(&ei->list)) { cleanup_ei(ei); - ei = NULL; + ei = ERR_PTR(-EBUSY); } return ei; }