* [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path
@ 2026-06-26 15:11 WenTao Liang
2026-06-28 4:03 ` WenTao Liang
2026-08-07 20:35 ` kernel test robot
0 siblings, 2 replies; 3+ messages in thread
From: WenTao Liang @ 2026-06-26 15:11 UTC (permalink / raw)
To: Lee Jones, linux-kernel; +Cc: stable, WenTao Liang
of_reset_control_get_optional_exclusive acquires a reset control
reference. On the success path, the function stores regmap and np but
does not store or release the reset handle. Only error paths call
reset_control_put to release it. This leaks the reset control reference
on the success path.
Store the reset handle in syscon->reset so it can be properly managed.
Cc: stable@vger.kernel.org
Fixes: 7d1e3bd94828 ("mfd: syscon: Allow reset control for syscon devices")
Signed-off-by: WenTao Liang <vulab@iscas.ac.cn>
---
drivers/mfd/syscon.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index 21a7fcdd2737..28576a3c02fd 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -148,6 +148,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
syscon->regmap = regmap;
syscon->np = np;
+ syscon->reset = reset;
list_add_tail(&syscon->list, &syscon_list);
--
2.39.5 (Apple Git-154)
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path
2026-06-26 15:11 [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path WenTao Liang
@ 2026-06-28 4:03 ` WenTao Liang
2026-08-07 20:35 ` kernel test robot
1 sibling, 0 replies; 3+ messages in thread
From: WenTao Liang @ 2026-06-28 4:03 UTC (permalink / raw)
To: Lee Jones, linux-kernel; +Cc: stable
> 2026年6月26日 23:11，WenTao Liang <vulab@iscas.ac.cn> 写道：
>
> of_reset_control_get_optional_exclusive acquires a reset control
> reference. On the success path, the function stores regmap and np but
> does not store or release the reset handle. Only error paths call
> reset_control_put to release it. This leaks the reset control reference
> on the success path.
>
> Store the reset handle in syscon->reset so it can be properly managed.
>
> Cc: stable@vger.kernel.org
> Fixes: 7d1e3bd94828 ("mfd: syscon: Allow reset control for syscon devices")
> Signed-off-by: WenTao Liang <vulab@iscas.ac.cn>
> ---
> drivers/mfd/syscon.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index 21a7fcdd2737..28576a3c02fd 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -148,6 +148,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
>
> syscon->regmap = regmap;
> syscon->np = np;
> + syscon->reset = reset;
>
> list_add_tail(&syscon->list, &syscon_list);
>
> --
> 2.39.5 (Apple Git-154)
Please ignore this patch. I will resend a proper version after
learning the kernel submission process.
Apologies for the noise.
Best regards,
WenTao Liang
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path
2026-06-26 15:11 [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path WenTao Liang
2026-06-28 4:03 ` WenTao Liang
@ 2026-08-07 20:35 ` kernel test robot
1 sibling, 0 replies; 3+ messages in thread
From: kernel test robot @ 2026-08-07 20:35 UTC (permalink / raw)
To: WenTao Liang, Lee Jones, linux-kernel
Cc: llvm, oe-kbuild-all, stable, WenTao Liang
Hi WenTao,
kernel test robot noticed the following build warnings:
[auto build test WARNING on lee-mfd/for-mfd-next]
[also build test WARNING on lee-mfd/for-mfd-fixes lee-leds/for-leds-next linus/master v7.2-rc6 next-20260807]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/WenTao-Liang/fix-mfd-of_syscon_register-fix-reset_control-reference-leak-on-success-path/20260807-005058
base: https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git for-mfd-next
patch link: https://lore.kernel.org/r/20260626151125.50780-1-vulab%40iscas.ac.cn
patch subject: [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path
config: loongarch-defconfig (https://download.01.org/0day-ci/archive/20260808/202608080440.vtPTMqD3-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 12df34b8469b8095359de8c249cb1b2753fadeea)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260808/202608080440.vtPTMqD3-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202608080440.vtPTMqD3-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/mfd/syscon.c:125:6: warning: variable 'reset' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
125 | if (check_res) {
| ^~~~~~~~~
drivers/mfd/syscon.c:151:18: note: uninitialized use occurs here
151 | syscon->reset = reset;
| ^~~~~
drivers/mfd/syscon.c:125:2: note: remove the 'if' if its condition is always true
125 | if (check_res) {
| ^~~~~~~~~~~~~~
drivers/mfd/syscon.c:49:29: note: initialize the variable 'reset' to silence this warning
49 | struct reset_control *reset;
| ^
| = NULL
1 warning generated.
vim +125 drivers/mfd/syscon.c
87d687301f3807 Dong Aisheng 2012-09-05 39
7d1e3bd94828ad Jeremy Kerr 2023-01-05 40 static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
87d687301f3807 Dong Aisheng 2012-09-05 41 {
a00406b71c5f08 Fabrice Gasnier 2018-12-12 42 struct clk *clk;
bdb0066df96e74 Pankaj Dubey 2014-09-30 43 struct regmap *regmap;
bdb0066df96e74 Pankaj Dubey 2014-09-30 44 void __iomem *base;
db2fb60cd35d2d Damien Riegel 2015-11-30 45 u32 reg_io_width;
bdb0066df96e74 Pankaj Dubey 2014-09-30 46 int ret;
bdb0066df96e74 Pankaj Dubey 2014-09-30 47 struct regmap_config syscon_config = syscon_regmap_config;
ca668f0edfae65 Philipp Zabel 2016-01-29 48 struct resource res;
7d1e3bd94828ad Jeremy Kerr 2023-01-05 49 struct reset_control *reset;
ba09916efb29f8 Eder Zulian 2025-02-12 50 resource_size_t res_size;
bdb0066df96e74 Pankaj Dubey 2014-09-30 51
805f7aaf7fee14 Rob Herring (Arm 2024-12-17 52) WARN_ON(!mutex_is_locked(&syscon_list_lock));
805f7aaf7fee14 Rob Herring (Arm 2024-12-17 53)
bf4afc53b77aea Linus Torvalds 2026-02-21 54 struct syscon *syscon __free(kfree) = kzalloc_obj(*syscon);
bdb0066df96e74 Pankaj Dubey 2014-09-30 55 if (!syscon)
bdb0066df96e74 Pankaj Dubey 2014-09-30 56 return ERR_PTR(-ENOMEM);
bdb0066df96e74 Pankaj Dubey 2014-09-30 57
82f898f47112bc Krzysztof Kozlowski 2024-07-07 58 if (of_address_to_resource(np, 0, &res))
82f898f47112bc Krzysztof Kozlowski 2024-07-07 59 return ERR_PTR(-ENOMEM);
ca668f0edfae65 Philipp Zabel 2016-01-29 60
452d07413954ef Hector Martin 2021-08-23 61 base = of_iomap(np, 0);
82f898f47112bc Krzysztof Kozlowski 2024-07-07 62 if (!base)
82f898f47112bc Krzysztof Kozlowski 2024-07-07 63 return ERR_PTR(-ENOMEM);
bdb0066df96e74 Pankaj Dubey 2014-09-30 64
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 65 /* Parse the device's DT node for an endianness specification */
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 66 if (of_property_read_bool(np, "big-endian"))
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 67 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 68 else if (of_property_read_bool(np, "little-endian"))
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 69 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 70 else if (of_property_read_bool(np, "native-endian"))
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 71 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
ca4582c286aa44 Jason A. Donenfeld 2022-10-08 72
db2fb60cd35d2d Damien Riegel 2015-11-30 73 /*
db2fb60cd35d2d Damien Riegel 2015-11-30 74 * search for reg-io-width property in DT. If it is not provided,
db2fb60cd35d2d Damien Riegel 2015-11-30 75 * default to 4 bytes. regmap_init_mmio will return an error if values
db2fb60cd35d2d Damien Riegel 2015-11-30 76 * are invalid so there is no need to check them here.
db2fb60cd35d2d Damien Riegel 2015-11-30 77 */
db2fb60cd35d2d Damien Riegel 2015-11-30 78 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
db2fb60cd35d2d Damien Riegel 2015-11-30 79 if (ret)
db2fb60cd35d2d Damien Riegel 2015-11-30 80 reg_io_width = 4;
db2fb60cd35d2d Damien Riegel 2015-11-30 81
3bafc09e779710 Baolin Wang 2017-12-25 82 ret = of_hwspin_lock_get_id(np, 0);
3bafc09e779710 Baolin Wang 2017-12-25 83 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
3bafc09e779710 Baolin Wang 2017-12-25 84 syscon_config.use_hwlock = true;
3bafc09e779710 Baolin Wang 2017-12-25 85 syscon_config.hwlock_id = ret;
3bafc09e779710 Baolin Wang 2017-12-25 86 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
3bafc09e779710 Baolin Wang 2017-12-25 87 } else if (ret < 0) {
3bafc09e779710 Baolin Wang 2017-12-25 88 switch (ret) {
3bafc09e779710 Baolin Wang 2017-12-25 89 case -ENOENT:
3bafc09e779710 Baolin Wang 2017-12-25 90 /* Ignore missing hwlock, it's optional. */
3bafc09e779710 Baolin Wang 2017-12-25 91 break;
3bafc09e779710 Baolin Wang 2017-12-25 92 default:
3bafc09e779710 Baolin Wang 2017-12-25 93 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
df561f6688fef7 Gustavo A. R. Silva 2020-08-23 94 fallthrough;
3bafc09e779710 Baolin Wang 2017-12-25 95 case -EPROBE_DEFER:
3bafc09e779710 Baolin Wang 2017-12-25 96 goto err_regmap;
3bafc09e779710 Baolin Wang 2017-12-25 97 }
3bafc09e779710 Baolin Wang 2017-12-25 98 }
3bafc09e779710 Baolin Wang 2017-12-25 99
ba09916efb29f8 Eder Zulian 2025-02-12 100 res_size = resource_size(&res);
ba09916efb29f8 Eder Zulian 2025-02-12 101 if (res_size < reg_io_width) {
ba09916efb29f8 Eder Zulian 2025-02-12 102 ret = -EFAULT;
ba09916efb29f8 Eder Zulian 2025-02-12 103 goto err_regmap;
ba09916efb29f8 Eder Zulian 2025-02-12 104 }
ba09916efb29f8 Eder Zulian 2025-02-12 105
7ff7d5ffb7259f Andy Shevchenko 2022-05-31 106 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
41673c66b3d0c0 Kunwu Chan 2023-12-04 107 if (!syscon_config.name) {
41673c66b3d0c0 Kunwu Chan 2023-12-04 108 ret = -ENOMEM;
41673c66b3d0c0 Kunwu Chan 2023-12-04 109 goto err_regmap;
41673c66b3d0c0 Kunwu Chan 2023-12-04 110 }
db2fb60cd35d2d Damien Riegel 2015-11-30 111 syscon_config.reg_stride = reg_io_width;
db2fb60cd35d2d Damien Riegel 2015-11-30 112 syscon_config.val_bits = reg_io_width * 8;
ba09916efb29f8 Eder Zulian 2025-02-12 113 syscon_config.max_register = res_size - reg_io_width;
2e63d6fa113d36 Nishanth Menon 2024-09-03 114 if (!syscon_config.max_register)
2e63d6fa113d36 Nishanth Menon 2024-09-03 115 syscon_config.max_register_is_0 = true;
db2fb60cd35d2d Damien Riegel 2015-11-30 116
bdb0066df96e74 Pankaj Dubey 2014-09-30 117 regmap = regmap_init_mmio(NULL, base, &syscon_config);
56a1188159cb2b Limeng 2021-04-07 118 kfree(syscon_config.name);
bdb0066df96e74 Pankaj Dubey 2014-09-30 119 if (IS_ERR(regmap)) {
bdb0066df96e74 Pankaj Dubey 2014-09-30 120 pr_err("regmap init failed\n");
bdb0066df96e74 Pankaj Dubey 2014-09-30 121 ret = PTR_ERR(regmap);
bdb0066df96e74 Pankaj Dubey 2014-09-30 122 goto err_regmap;
bdb0066df96e74 Pankaj Dubey 2014-09-30 123 }
bdb0066df96e74 Pankaj Dubey 2014-09-30 124
7d1e3bd94828ad Jeremy Kerr 2023-01-05 @125 if (check_res) {
a00406b71c5f08 Fabrice Gasnier 2018-12-12 126 clk = of_clk_get(np, 0);
a00406b71c5f08 Fabrice Gasnier 2018-12-12 127 if (IS_ERR(clk)) {
a00406b71c5f08 Fabrice Gasnier 2018-12-12 128 ret = PTR_ERR(clk);
a00406b71c5f08 Fabrice Gasnier 2018-12-12 129 /* clock is optional */
a00406b71c5f08 Fabrice Gasnier 2018-12-12 130 if (ret != -ENOENT)
a00406b71c5f08 Fabrice Gasnier 2018-12-12 131 goto err_clk;
a00406b71c5f08 Fabrice Gasnier 2018-12-12 132 } else {
a00406b71c5f08 Fabrice Gasnier 2018-12-12 133 ret = regmap_mmio_attach_clk(regmap, clk);
a00406b71c5f08 Fabrice Gasnier 2018-12-12 134 if (ret)
7d1e3bd94828ad Jeremy Kerr 2023-01-05 135 goto err_attach_clk;
a00406b71c5f08 Fabrice Gasnier 2018-12-12 136 }
7d1e3bd94828ad Jeremy Kerr 2023-01-05 137
7d1e3bd94828ad Jeremy Kerr 2023-01-05 138 reset = of_reset_control_get_optional_exclusive(np, NULL);
7d1e3bd94828ad Jeremy Kerr 2023-01-05 139 if (IS_ERR(reset)) {
7d1e3bd94828ad Jeremy Kerr 2023-01-05 140 ret = PTR_ERR(reset);
7d1e3bd94828ad Jeremy Kerr 2023-01-05 141 goto err_attach_clk;
7d1e3bd94828ad Jeremy Kerr 2023-01-05 142 }
7d1e3bd94828ad Jeremy Kerr 2023-01-05 143
7d1e3bd94828ad Jeremy Kerr 2023-01-05 144 ret = reset_control_deassert(reset);
7d1e3bd94828ad Jeremy Kerr 2023-01-05 145 if (ret)
7d1e3bd94828ad Jeremy Kerr 2023-01-05 146 goto err_reset;
39233b7c611248 Paul Cercueil 2019-07-24 147 }
a00406b71c5f08 Fabrice Gasnier 2018-12-12 148
bdb0066df96e74 Pankaj Dubey 2014-09-30 149 syscon->regmap = regmap;
bdb0066df96e74 Pankaj Dubey 2014-09-30 150 syscon->np = np;
daad85a71f976e WenTao Liang 2026-06-26 151 syscon->reset = reset;
bdb0066df96e74 Pankaj Dubey 2014-09-30 152
bdb0066df96e74 Pankaj Dubey 2014-09-30 153 list_add_tail(&syscon->list, &syscon_list);
87d687301f3807 Dong Aisheng 2012-09-05 154
82f898f47112bc Krzysztof Kozlowski 2024-07-07 155 return_ptr(syscon);
bdb0066df96e74 Pankaj Dubey 2014-09-30 156
7d1e3bd94828ad Jeremy Kerr 2023-01-05 157 err_reset:
7d1e3bd94828ad Jeremy Kerr 2023-01-05 158 reset_control_put(reset);
7d1e3bd94828ad Jeremy Kerr 2023-01-05 159 err_attach_clk:
a00406b71c5f08 Fabrice Gasnier 2018-12-12 160 if (!IS_ERR(clk))
a00406b71c5f08 Fabrice Gasnier 2018-12-12 161 clk_put(clk);
a00406b71c5f08 Fabrice Gasnier 2018-12-12 162 err_clk:
a00406b71c5f08 Fabrice Gasnier 2018-12-12 163 regmap_exit(regmap);
bdb0066df96e74 Pankaj Dubey 2014-09-30 164 err_regmap:
bdb0066df96e74 Pankaj Dubey 2014-09-30 165 iounmap(base);
bdb0066df96e74 Pankaj Dubey 2014-09-30 166 return ERR_PTR(ret);
87d687301f3807 Dong Aisheng 2012-09-05 167 }
87d687301f3807 Dong Aisheng 2012-09-05 168
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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2026-06-26 15:11 [PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path WenTao Liang
2026-06-28 4:03 ` WenTao Liang
2026-08-07 20:35 ` kernel test robot
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