mmc: sdio: fix possible resource leaks in some error paths

If sdio_add_func() or sdio_init_func() fails, sdio_remove_func() can
not release the resources, because the sdio function is not presented
in these two cases, it won't call of_node_put() or put_device().

To fix these leaks, make sdio_func_present() only control whether
device_del() needs to be called or not, then always call of_node_put()
and put_device().

In error case in sdio_init_func(), the reference of 'card->dev' is
not get, to avoid redundant put in sdio_free_func_cis(), move the
get_device() to sdio_alloc_func() and put_device() to sdio_release_func(),
it can keep the get/put function be balanced.

Without this patch, while doing fault inject test, it can get the
following leak reports, after this fix, the leak is gone.

unreferenced object 0xffff888112514000 (size 2048):
  comm "kworker/3:2", pid 65, jiffies 4294741614 (age 124.774s)
  hex dump (first 32 bytes):
    00 e0 6f 12 81 88 ff ff 60 58 8d 06 81 88 ff ff  ..o.....`X......
    10 40 51 12 81 88 ff ff 10 40 51 12 81 88 ff ff  .@q......@q.....
  backtrace:
    [<000000009e5931da>] kmalloc_trace+0x21/0x110
    [<000000002f839ccb>] mmc_alloc_card+0x38/0xb0 [mmc_core]
    [<0000000004adcbf6>] mmc_sdio_init_card+0xde/0x170 [mmc_core]
    [<000000007538fea0>] mmc_attach_sdio+0xcb/0x1b0 [mmc_core]
    [<00000000d4fdeba7>] mmc_rescan+0x54a/0x640 [mmc_core]

unreferenced object 0xffff888112511000 (size 2048):
  comm "kworker/3:2", pid 65, jiffies 4294741623 (age 124.766s)
  hex dump (first 32 bytes):
    00 40 51 12 81 88 ff ff e0 58 8d 06 81 88 ff ff  .@q......X......
    10 10 51 12 81 88 ff ff 10 10 51 12 81 88 ff ff  ..Q.......Q.....
  backtrace:
    [<000000009e5931da>] kmalloc_trace+0x21/0x110
    [<00000000fcbe706c>] sdio_alloc_func+0x35/0x100 [mmc_core]
    [<00000000c68f4b50>] mmc_attach_sdio.cold.18+0xb1/0x395 [mmc_core]
    [<00000000d4fdeba7>] mmc_rescan+0x54a/0x640 [mmc_core]

Fixes: 3d10a1b ("sdio: fix reference counting in sdio_remove_func()")
Signed-off-by: Yang Yingliang <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: Yang Yingliang

drivers/mmc/core/sdio_bus.c

@@ -294,6 +294,12 @@ static void sdio_release_func(struct device *dev)
 	if (!(func->card->quirks & MMC_QUIRK_NONSTD_SDIO))
 		sdio_free_func_cis(func);
 
+	/*
+	 * We have now removed the link to the tuples in the
+	 * card structure, so remove the reference.
+	 */
+	put_device(&func->card->dev);
+
 	kfree(func->info);
 	kfree(func->tmpbuf);
 	kfree(func);
@@ -324,6 +330,12 @@ struct sdio_func *sdio_alloc_func(struct mmc_card *card)
 
 	device_initialize(&func->dev);
 
+	/*
+	 * We may link to tuples in the card structure,
+	 * we need make sure we have a reference to it.
+	 */
+	get_device(&func->card->dev);
+
 	func->dev.parent = &card->dev;
 	func->dev.bus = &sdio_bus_type;
 	func->dev.release = sdio_release_func;
@@ -377,10 +389,9 @@ int sdio_add_func(struct sdio_func *func)
  */
 void sdio_remove_func(struct sdio_func *func)
 {
-	if (!sdio_func_present(func))
-		return;
+	if (sdio_func_present(func))
+		device_del(&func->dev);
 
-	device_del(&func->dev);
 	of_node_put(func->dev.of_node);
 	put_device(&func->dev);
 }

drivers/mmc/core/sdio_cis.c

@@ -403,12 +403,6 @@ int sdio_read_func_cis(struct sdio_func *func)
 	if (ret)
 		return ret;
 
-	/*
-	 * Since we've linked to tuples in the card structure,
-	 * we must make sure we have a reference to it.
-	 */
-	get_device(&func->card->dev);
-
 	/*
 	 * Vendor/device id is optional for function CIS, so
 	 * copy it from the card structure as needed.
@@ -434,11 +428,5 @@ void sdio_free_func_cis(struct sdio_func *func)
 	}
 
 	func->tuples = NULL;
-
-	/*
-	 * We have now removed the link to the tuples in the
-	 * card structure, so remove the reference.
-	 */
-	put_device(&func->card->dev);
 }