[PATCH] fix: mfd: of_syscon_register: fix reset_control reference leak on success path

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* [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", &reg_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

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2026-08-07 20:35 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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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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