gpio: shared: fix memory leaks

dblueman · Bartosz Golaszewski · commit 32e0a7ad9c84 · 2026-02-23T11:01:13.000+01:00
On a Snapdragon X1 Elite laptop (Lenovo Yoga Slim 7x), kmemleak reports three sets of: unreferenced object 0xffff00080187f400 (size 1024): comm "swapper/0", pid 1, jiffies 4294667327 hex dump (first 32 bytes): 58 bd 70 01 08 00 ff ff 58 bd 70 01 08 00 ff ff X.p.....X.p..... 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ backtrace (crc 1665d1f8): kmemleak_alloc+0xf4/0x12c __kmalloc_cache_noprof+0x370/0x49c gpio_shared_make_ref+0x70/0x16c gpio_shared_of_traverse+0x4e8/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_init+0x34/0x1c4 do_one_initcall+0x50/0x280 kernel_init_freeable+0x290/0x33c kernel_init+0x28/0x14c ret_from_fork+0x10/0x20 unreferenced object 0xffff00080170c140 (size 8): comm "swapper/0", pid 1, jiffies 4294667327 hex dump (first 8 bytes): 72 65 73 65 74 00 00 00 reset... backtrace (crc fc24536): kmemleak_alloc+0xf4/0x12c __kmalloc_node_track_caller_noprof+0x3c4/0x584 kstrdup+0x4c/0xcc gpio_shared_make_ref+0x8c/0x16c gpio_shared_of_traverse+0x4e8/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_init+0x34/0x1c4 do_one_initcall+0x50/0x280 kernel_init_freeable+0x290/0x33c kernel_init+0x28/0x14c ret_from_fork+0x10/0x20 Fix this by decrementing the reference count of each list entry rather than only the first. Fix verified on the same laptop. Fixes: a060b8c gpiolib: implement low-level, shared GPIO support Signed-off-by: Daniel J Blueman <daniel@quora.org> Link: https://patch.msgid.link/20260220093452.101655-1-daniel@quora.org Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c
@@ -748,14 +748,14 @@ static bool gpio_shared_entry_is_really_shared(struct gpio_shared_entry *entry)
 static void gpio_shared_free_exclusive(void)
 {
 	struct gpio_shared_entry *entry, *epos;
+	struct gpio_shared_ref *ref, *rpos;
 
 	list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) {
 		if (gpio_shared_entry_is_really_shared(entry))
 			continue;
 
-		gpio_shared_drop_ref(list_first_entry(&entry->refs,
-						      struct gpio_shared_ref,
-						      list));
+		list_for_each_entry_safe(ref, rpos, &entry->refs, list)
+			gpio_shared_drop_ref(ref);
 		gpio_shared_drop_entry(entry);
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -748,14 +748,14 @@ static bool gpio_shared_entry_is_really_shared(struct gpio_shared_entry *entry)`
`748`	`748`	`static void gpio_shared_free_exclusive(void)`
`749`	`749`	`{`
`750`	`750`	`struct gpio_shared_entry entry, epos;`
	`751`	`+ struct gpio_shared_ref ref, rpos;`
`751`	`752`
`752`	`753`	`list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) {`
`753`	`754`	`if (gpio_shared_entry_is_really_shared(entry))`
`754`	`755`	`continue;`
`755`	`756`
`756`		`- gpio_shared_drop_ref(list_first_entry(&entry->refs,`
`757`		`- struct gpio_shared_ref,`
`758`		`- list));`
	`757`	`+ list_for_each_entry_safe(ref, rpos, &entry->refs, list)`
	`758`	`+ gpio_shared_drop_ref(ref);`
`759`	`759`	`gpio_shared_drop_entry(entry);`
`760`	`760`	`}`
`761`	`761`	`}`