Messages in this thread | | | Date | Wed, 03 Aug 2011 16:12:31 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86, efi: Don't recursively acquire rtc_lock |
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On 08/03/2011 02:04 PM, Matt Fleming wrote: > From: Matt Fleming <matt.fleming@linux.intel.com> > > A deadlock was introduced on x86 in commit ef68c8f87ed1 ("x86: > Serialize EFI time accesses on rtc_lock") because efi_get_time() and > friends can be called with rtc_lock already held by > read_persistent_time(), e.g. > > timekeeping_init() > read_persistent_clock() <-- acquire rtc_lock > efi_get_time() > phys_efi_get_time() <-- acquire rtc_lock <DEADLOCK> > > Move the locking up into the caller of efi.get_time() and provide some > wrappers for use in other parts of the kernel instead of calling > efi.get_time(), etc directly. This way we can hide the rtc_lock dance > inside of arch/x86. > > Cc: Jan Beulich <JBeulich@novell.com> > Cc: Matthew Garrett <mjg@redhat.com> > Cc: "H. Peter Anvin" <hpa@linux.intel.com> > Cc: Tony Luck <tony.luck@intel.com> > Cc: Fenghua Yu <fenghua.yu@intel.com> > Cc: Alessandro Zummo <a.zummo@towertech.it> > Signed-off-by: Matt Fleming <matt.fleming@linux.intel.com>
For the x86 footprint:
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
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