In i2c_amd_probe(), amd_mp2_find_device() utilizes driver_find_next_device() which internally calls driver_find_device() to locate the matching device. driver_find_device() increments the reference count of the found device by calling get_device(), but amd_mp2_find_device() fails to call put_device() to decrement the reference count before returning. This results in a reference count leak of the PCI device each time i2c_amd_probe() is executed, which may prevent the device from being properly released and cause a memory leak.
Found by code review.
Cc: stable@vger.kernel.org Fixes: 529766e0a011 ("i2c: Add drivers for the AMD PCIe MP2 I2C controller") Signed-off-by: Ma Ke make24@iscas.ac.cn --- drivers/i2c/busses/i2c-amd-mp2-pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-amd-mp2-pci.c b/drivers/i2c/busses/i2c-amd-mp2-pci.c index ef7370d3dbea..1f01d3f121ba 100644 --- a/drivers/i2c/busses/i2c-amd-mp2-pci.c +++ b/drivers/i2c/busses/i2c-amd-mp2-pci.c @@ -464,7 +464,9 @@ struct amd_mp2_dev *amd_mp2_find_device(void) return NULL;
pci_dev = to_pci_dev(dev); - return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev); + mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev); + put_device(dev); + return mp2_dev; } EXPORT_SYMBOL_GPL(amd_mp2_find_device);
In i2c_amd_probe(), amd_mp2_find_device() utilizes driver_find_next_device() which internally calls driver_find_device() to locate the matching device. driver_find_device() increments the reference count of the found device by calling get_device(), but amd_mp2_find_device() fails to call put_device() to decrement the reference count before returning. This results in a reference count leak of the PCI device each time i2c_amd_probe() is executed, which may prevent the device from being properly released and cause a memory leak.
How do you think about to increase the application of scope-based resource management? https://elixir.bootlin.com/linux/v6.17-rc7/source/include/linux/device.h#L11...
Regards, Markus
On Sat, Sep 27, 2025 at 02:56:49PM +0200, Markus Elfring wrote:
In i2c_amd_probe(), amd_mp2_find_device() utilizes driver_find_next_device() which internally calls driver_find_device() to locate the matching device. driver_find_device() increments the reference count of the found device by calling get_device(), but amd_mp2_find_device() fails to call put_device() to decrement the reference count before returning. This results in a reference count leak of the PCI device each time i2c_amd_probe() is executed, which may prevent the device from being properly released and cause a memory leak.
How do you think about to increase the application of scope-based resource management? https://elixir.bootlin.com/linux/v6.17-rc7/source/include/linux/device.h#L11...
Regards, Markus
Hi,
This is the semi-friendly patch-bot of Greg Kroah-Hartman.
Markus, you seem to have sent a nonsensical or otherwise pointless review comment to a patch submission on a Linux kernel developer mailing list. I strongly suggest that you not do this anymore. Please do not bother developers who are actively working to produce patches and features with comments that, in the end, are a waste of time.
Patch submitter, please ignore Markus's suggestion; you do not need to follow it at all. The person/bot/AI that sent it is being ignored by almost all Linux kernel maintainers for having a persistent pattern of behavior of producing distracting and pointless commentary, and inability to adapt to feedback. Please feel free to also ignore emails from them.
thanks,
greg k-h's patch email bot
Hi Ma,
kernel test robot noticed the following build warnings:
[auto build test WARNING on andi-shyti/i2c/i2c-host] [also build test WARNING on linus/master v6.17-rc7 next-20250926] [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/Ma-Ke/i2c-fix-reference-leak-... base: https://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git i2c/i2c-host patch link: https://lore.kernel.org/r/20250927105729.19164-1-make24%40iscas.ac.cn patch subject: [PATCH] i2c: fix reference leak in MP2 PCI device config: i386-randconfig-013-20250928 (https://download.01.org/0day-ci/archive/20250928/202509281110.ACsS1CDz-lkp@i...) compiler: gcc-14 (Debian 14.2.0-19) 14.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250928/202509281110.ACsS1CDz-lkp@i...)
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/202509281110.ACsS1CDz-lkp@intel.com/
All warnings (new ones prefixed by >>):
drivers/i2c/busses/i2c-amd-mp2-pci.c: In function 'amd_mp2_find_device': drivers/i2c/busses/i2c-amd-mp2-pci.c:467:9: error: 'mp2_dev' undeclared (first use in this function) 467 | mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev); | ^~~~~~~ drivers/i2c/busses/i2c-amd-mp2-pci.c:467:9: note: each undeclared identifier is reported only once for each function it appears in
drivers/i2c/busses/i2c-amd-mp2-pci.c:470:1: warning: control reaches end of non-void function [-Wreturn-type]
470 | } | ^
vim +470 drivers/i2c/busses/i2c-amd-mp2-pci.c
529766e0a01144 Elie Morisse 2019-03-05 456 529766e0a01144 Elie Morisse 2019-03-05 457 struct amd_mp2_dev *amd_mp2_find_device(void) 529766e0a01144 Elie Morisse 2019-03-05 458 { 529766e0a01144 Elie Morisse 2019-03-05 459 struct device *dev; 529766e0a01144 Elie Morisse 2019-03-05 460 struct pci_dev *pci_dev; 529766e0a01144 Elie Morisse 2019-03-05 461 6bf85ba9e55f65 Suzuki K Poulose 2019-07-23 462 dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL); 529766e0a01144 Elie Morisse 2019-03-05 463 if (!dev) 529766e0a01144 Elie Morisse 2019-03-05 464 return NULL; 529766e0a01144 Elie Morisse 2019-03-05 465 529766e0a01144 Elie Morisse 2019-03-05 466 pci_dev = to_pci_dev(dev); 10a231ddf6f43e Ma Ke 2025-09-27 467 mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev); 10a231ddf6f43e Ma Ke 2025-09-27 468 put_device(dev); 10a231ddf6f43e Ma Ke 2025-09-27 469 return mp2_dev; 529766e0a01144 Elie Morisse 2019-03-05 @470 } 529766e0a01144 Elie Morisse 2019-03-05 471 EXPORT_SYMBOL_GPL(amd_mp2_find_device); 529766e0a01144 Elie Morisse 2019-03-05 472
Hi Ma,
kernel test robot noticed the following build errors:
[auto build test ERROR on andi-shyti/i2c/i2c-host] [also build test ERROR on linus/master v6.17-rc7 next-20250926] [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/Ma-Ke/i2c-fix-reference-leak-... base: https://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git i2c/i2c-host patch link: https://lore.kernel.org/r/20250927105729.19164-1-make24%40iscas.ac.cn patch subject: [PATCH] i2c: fix reference leak in MP2 PCI device config: i386-randconfig-011-20250928 (https://download.01.org/0day-ci/archive/20250928/202509281317.3OLDoUnB-lkp@i...) compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250928/202509281317.3OLDoUnB-lkp@i...)
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/202509281317.3OLDoUnB-lkp@intel.com/
All errors (new ones prefixed by >>):
drivers/i2c/busses/i2c-amd-mp2-pci.c:467:2: error: use of undeclared identifier 'mp2_dev'
467 | mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev); | ^ drivers/i2c/busses/i2c-amd-mp2-pci.c:469:9: error: use of undeclared identifier 'mp2_dev'; did you mean 'pci_dev'? 469 | return mp2_dev; | ^~~~~~~ | pci_dev drivers/i2c/busses/i2c-amd-mp2-pci.c:460:18: note: 'pci_dev' declared here 460 | struct pci_dev *pci_dev; | ^
drivers/i2c/busses/i2c-amd-mp2-pci.c:469:9: error: incompatible pointer types returning 'struct pci_dev *' from a function with result type 'struct amd_mp2_dev *' [-Werror,-Wincompatible-pointer-types]
469 | return mp2_dev; | ^~~~~~~ 3 errors generated.
vim +/mp2_dev +467 drivers/i2c/busses/i2c-amd-mp2-pci.c
456 457 struct amd_mp2_dev *amd_mp2_find_device(void) 458 { 459 struct device *dev; 460 struct pci_dev *pci_dev; 461 462 dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL); 463 if (!dev) 464 return NULL; 465 466 pci_dev = to_pci_dev(dev);
467 mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
468 put_device(dev);
469 return mp2_dev;
470 } 471 EXPORT_SYMBOL_GPL(amd_mp2_find_device); 472
linux-stable-mirror@lists.linaro.org
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Greg KH -
kernel test robot -
Ma Ke -
Markus Elfring