Thanks Shannon! Todd Fujinaka Software Application Engineer Data Center Group Intel Corporation todd.fujin...@intel.com
-----Original Message----- From: Shannon Nelson <snel...@pensando.io> Sent: Tuesday, March 9, 2021 3:28 PM To: e1000-devel@lists.sourceforge.net Subject: [E1000-devel] kcompat landmine - devm_kcalloc Hi folks, I just spent a very long time debugging a random kernel panic that was coming from some sort of memory scribbling in our ionic driver, and found the culprit in the kcompat.h code that we've borrowed from Intel drivers. I thought I'd let you know before someone else hit this. You'll probably want to check this in all your out-of-tree drivers. Thanks for making this chunk of code available to the world. Here's the world giving back to you. Cheers, sln kcompat: add parens to devm_kcalloc macro The macro in kcompat for devm_kcalloc() uses its parameters in a multiplication in a call to devm_kzalloc(), but didn't protect those parameters with ()'s. This caused havoc and several days debugging a random kernel panic when one parameter was essentially a + b: the resulting order of operations didn't allocate the expected amount of memory and we ended up scribbling over random other objects, causing great pain, chaos, and gnashing of teeth. Signed-off-by: Shannon Nelson <snel...@pensando.io> diff --git a/platform/drivers/linux/eth/ionic/kcompat.h b/platform/drivers/linux/eth/ionic/kcompat.h index 12c4361d2a..a87428b4e6 100644 --- a/platform/drivers/linux/eth/ionic/kcompat.h +++ b/platform/drivers/linux/eth/ionic/kcompat.h @@ -5003,7 +5003,7 @@ static inline struct pci_dev *pci_upstream_bridge(struct pci_dev *dev) #if ( LINUX_VERSION_CODE > KERNEL_VERSION(2,6,20) ) #define devm_kcalloc(dev, cnt, size, flags) \ - devm_kzalloc(dev, cnt * size, flags) + devm_kzalloc(dev, (cnt) * (size), flags) #endif /* > 2.6.20 */ #if (!(RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(7,2))) _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel Ethernet, visit https://forums.intel.com/s/topic/0TO0P00000018NbWAI/intel-ethernet _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel Ethernet, visit https://forums.intel.com/s/topic/0TO0P00000018NbWAI/intel-ethernet
