[Problem] There are following problems related to an interrupt context in efivar/efi_pstore.
Currently, efivars enables interrupt while taking efivars->lock. So, there is a risk to be deadlocking in a write callback of efi_pstore if kernel panics in interrupt context while taking efi_lock. Also, efi_pstore creates sysfs entries ,which enable users to access to NVRAM, in a write callback. If a kernel panic happens in interrupt contexts, pstore may fail because it could sleep due to dynamic memory allocations during creating sysfs entries. To resolve the problems above, a goal of this patchset is making efivars/efi_pstore interrupt-safe. [Patch Description] Patch 1/2 efivars: Disable external interrupt while holding efivars->lock This patch replaces spin_lock/spin_unlock with spin_lock_irqsave/spin_lock_irqrestore to make efivars interrupt safe Patch 2/2 efi_pstore: Introducing workqueue updating sysfs entries This patch removes sysfs operations from write callback by introducing a workqueue updating sysfs entries drivers/firmware/efivars.c | 193 +++++++++++++++++++++++++++++++++++--------- include/linux/efi.h | 6 +- 2 files changed, 161 insertions(+), 38 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
