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mpt2sas: setpci reset on nytro warpdrive card along with sysfs access and cli ioctl access resulted in kernel oops 1. pci_access_mutex lock added to provide synchronization between IOCTL, sysfs, PCI resource handling path 2. gioc_lock spinlock to protect list operations over multiple controllers >From c53a1cff4c07528b8b9ec7f6716e94950283e8f9 Mon Sep 17 00:00:00 2001 From: Nagarajkumar Narayanan <nagarajkumar.narayanan@seagate.com> Date: Tue, 18 Aug 2015 11:58:13 +0530 Subject: [PATCH] mpt2sas setpci reset oops fix In mpt2sas driver due to lack of synchronization between ioctl, BRM status access through sysfs, pci resource removal kernel oops happen as ioctl path and BRM status sysfs access path still tries to access the removed resources Two locks added to provide syncrhonization 1. pci_access_mutex: Mutex to synchronize ioctl,sysfs show path and pci resource handling. PCI resource freeing will lead to free vital hardware/memory resource, which might be in use by cli/sysfs path functions resulting in Null pointer reference followed by kernel crash. To avoid the above race condition we use mutex syncrhonization which ensures the syncrhonization between cli/sysfs_show path Note: pci_access_mutex is used only if nytro warpdrive cards (ioc->is_warpdrive based on device id) are used as we could not test this case with other SAS2 HBA cards We can remove this check if this behaviour confirmed from other cards. 2. spinlock on list operations over IOCs Case: when multiple warpdrive cards(IOCs) are in use Each IOC will added to the ioc list stucture on initialization. Watchdog threads run at regular intervals to check IOC for any fault conditions which will trigger the dead_ioc thread to deallocate pci resource, resulting deleting the IOC netry from list, this deletion need to protected by spinlock to enusre that ioc removal is syncrhonized, if not synchronized it might lead to list_del corruption as the ioc list is traversed in cli path Signed-off-by: Nagarajkumar Narayanan <nagarajkumar.narayanan@seagate.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Acked-by: Sreekanth Reddy <sreekanth.reddy@avagotech.com> Signed-off-by: James Bottomley <JBottomley@Odin.com> |
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| .. | ||
| mpi | ||
| Kconfig | ||
| Makefile | ||
| mpt2sas_base.c | ||
| mpt2sas_base.h | ||
| mpt2sas_config.c | ||
| mpt2sas_ctl.c | ||
| mpt2sas_ctl.h | ||
| mpt2sas_debug.h | ||
| mpt2sas_scsih.c | ||
| mpt2sas_transport.c | ||