[PATCH] io_uring/rsrc: Move lockdep assert from io_free_rsrc_node() to caller

[PATCH] io_uring/rsrc: Move lockdep assert from io_free_rsrc_node() to caller

[Jann Horn]

Checking for lockdep_assert_held(&ctx->uring_lock) in io_free_rsrc_node()
means that the assertion is only checked when the resource drops to zero
references.
Move the lockdep assertion up into the caller io_put_rsrc_node() so that it
instead happens on every reference count decrement.

Signed-off-by: Jann Horn <jannh@google.com>
---
 io_uring/rsrc.c | 2 --
 io_uring/rsrc.h | 3 +++
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index a5fc035af8ff910d423930d7c662cc0e1a9f8444..af39b69eb4fde8b6e478e71c36dc04d3eec1b6d1 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -444,8 +444,6 @@ int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
 
 void io_free_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
 {
-	lockdep_assert_held(&ctx->uring_lock);
-
 	if (node->tag)
 		io_post_aux_cqe(ctx, node->tag, 0, 0);
 
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 5cd00b7baef8b03dd5f4a3aacee859b37db98e9b..190f7ee45de933b39a8c4d33dc86f687e338eb16 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -2,6 +2,8 @@
 #ifndef IOU_RSRC_H
 #define IOU_RSRC_H
 
+#include <linux/lockdep.h>
+
 #define IO_NODE_ALLOC_CACHE_MAX 32
 
 #define IO_RSRC_TAG_TABLE_SHIFT	(PAGE_SHIFT - 3)
@@ -80,6 +82,7 @@ static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data
 
 static inline void io_put_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
 {
+	lockdep_assert_held(&ctx->uring_lock);
 	if (node && !--node->refs)
 		io_free_rsrc_node(ctx, node);
 }

---
base-commit: e8153972dea537f1ae3ac45355fe3b2b3cbf59bf
change-id: 20250120-uring-lockdep-assert-earlier-264e039fafe5

-- 
Jann Horn <jannh@google.com>

Re: [PATCH] io_uring/rsrc: Move lockdep assert from io_free_rsrc_node() to caller

[Jens Axboe]

On Mon, 20 Jan 2025 17:21:57 +0100, Jann Horn wrote:
> Checking for lockdep_assert_held(&ctx->uring_lock) in io_free_rsrc_node()
> means that the assertion is only checked when the resource drops to zero
> references.
> Move the lockdep assertion up into the caller io_put_rsrc_node() so that it
> instead happens on every reference count decrement.
> 
> 
> [...]

Applied, thanks!

[1/1] io_uring/rsrc: Move lockdep assert from io_free_rsrc_node() to caller
      commit: 8c4b2fd5908d2260dfac8d4b74aae1bb5deea379

Best regards,
-- 
Jens Axboe