| Message ID | 20241001225207.2215639-4-andrii@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | uprobes,mm: speculative lockless VMA-to-uprobe lookup | expand |
diff --git a/fs/file_table.c b/fs/file_table.c index ca7843dde56d..257691d358ee 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -68,7 +68,7 @@ static inline void file_free(struct file *f) put_cred(f->f_cred); if (unlikely(f->f_mode & FMODE_BACKING)) { path_put(backing_file_user_path(f)); - kfree(backing_file(f)); + kfree_rcu_mightsleep(backing_file(f)); } else { kmem_cache_free(filp_cachep, f); }
6cf41fcfe099 ("backing file: free directly") switched FMODE_BACKING files to direct freeing as back then there were no use cases requiring RCU protected access to such files. Now, with speculative lockless VMA-to-uprobe lookup logic, we do need to have a guarantee that struct file memory is not going to be freed from under us during speculative check. So add back RCU-delayed freeing logic. We use headless kfree_rcu_mightsleep() variant, as file_free() is only called for FMODE_BACKING files in might_sleep() context. Suggested-by: Suren Baghdasaryan <surenb@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)