> v3 changes: > a. drop the changes to CoreGetIoSpaceMap() because it won't cause > problem > b. refine the logic in changes of CoreGetMemorySpaceMap() > and add more comments
This issue is hidden in current code but exposed by introduction of freed-memory guard feature due to the fact that the feature will turn all pool allocation to page allocation. The solution is move the memory allocation in CoreGetMemorySpaceMap() and CoreGetIoSpaceMap() to be out of the GCD memory map lock. Although it's rare, a while-loop is added to make sure that the count of descriptor of memory map is the same after memory allocation, because it's executed outside the GCD memory lock. CoreDumpGcdMemorySpaceMap() => CoreGetMemorySpaceMap() => CoreAcquireGcdMemoryLock () * AllocatePool() => InternalAllocatePool() => CoreAllocatePool() => CoreAllocatePoolI() => CoreAllocatePoolPagesI() => CoreAllocatePoolPages() => FindFreePages() => PromoteMemoryResource() => CoreAcquireGcdMemoryLock() ** Cc: Star Zeng <[email protected]> Cc: Michael D Kinney <[email protected]> Cc: Jiewen Yao <[email protected]> Cc: Ruiyu Ni <[email protected]> Cc: Laszlo Ersek <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang <[email protected]> --- MdeModulePkg/Core/Dxe/Gcd/Gcd.c | 80 +++++++++++++++++++++++++++-------------- 1 file changed, 54 insertions(+), 26 deletions(-) diff --git a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c index d9c65a8045..bc02945721 100644 --- a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c +++ b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c @@ -1691,10 +1691,10 @@ CoreGetMemorySpaceMap ( OUT EFI_GCD_MEMORY_SPACE_DESCRIPTOR **MemorySpaceMap ) { - EFI_STATUS Status; LIST_ENTRY *Link; EFI_GCD_MAP_ENTRY *Entry; EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Descriptor; + UINTN DescriptorCount; // // Make sure parameters are valid @@ -1706,38 +1706,66 @@ CoreGetMemorySpaceMap ( return EFI_INVALID_PARAMETER; } + *NumberOfDescriptors = 0; + *MemorySpaceMap = NULL; + CoreAcquireGcdMemoryLock (); - // - // Count the number of descriptors - // - *NumberOfDescriptors = CoreCountGcdMapEntry (&mGcdMemorySpaceMap); + while (TRUE) { + // + // Count the number of descriptors. It might be done more than once because + // there's code which has to be running outside the GCD lock. + // + DescriptorCount = CoreCountGcdMapEntry (&mGcdMemorySpaceMap); + if (DescriptorCount == *NumberOfDescriptors) { + // + // Fill in the MemorySpaceMap if no memory space map change. + // + Descriptor = *MemorySpaceMap; + Link = mGcdMemorySpaceMap.ForwardLink; + while (Link != &mGcdMemorySpaceMap) { + Entry = CR (Link, EFI_GCD_MAP_ENTRY, Link, EFI_GCD_MAP_SIGNATURE); + BuildMemoryDescriptor (Descriptor, Entry); + Descriptor++; + Link = Link->ForwardLink; + } - // - // Allocate the MemorySpaceMap - // - *MemorySpaceMap = AllocatePool (*NumberOfDescriptors * sizeof (EFI_GCD_MEMORY_SPACE_DESCRIPTOR)); - if (*MemorySpaceMap == NULL) { - Status = EFI_OUT_OF_RESOURCES; - goto Done; - } + break; + } - // - // Fill in the MemorySpaceMap - // - Descriptor = *MemorySpaceMap; - Link = mGcdMemorySpaceMap.ForwardLink; - while (Link != &mGcdMemorySpaceMap) { - Entry = CR (Link, EFI_GCD_MAP_ENTRY, Link, EFI_GCD_MAP_SIGNATURE); - BuildMemoryDescriptor (Descriptor, Entry); - Descriptor++; - Link = Link->ForwardLink; + // + // Release the lock before memory allocation, because it might cause + // GCD lock conflict in one of calling path in AllocatPool(). + // + CoreReleaseGcdMemoryLock (); + + // + // Allocate memory to store the MemorySpaceMap. Note it might be already + // allocated if there's map descriptor change during memory allocation at + // last time. + // + if (*MemorySpaceMap != NULL) { + FreePool (*MemorySpaceMap); + } + + *MemorySpaceMap = AllocatePool (DescriptorCount * + sizeof (EFI_GCD_MEMORY_SPACE_DESCRIPTOR)); + if (*MemorySpaceMap == NULL) { + *NumberOfDescriptors = 0; + return EFI_OUT_OF_RESOURCES; + } + + // + // Save the descriptor number got before for another round of check to make + // sure we won't miss any, since we have code running outside the GCD lock. + // + *NumberOfDescriptors = DescriptorCount; + CoreAcquireGcdMemoryLock (); } - Status = EFI_SUCCESS; -Done: CoreReleaseGcdMemoryLock (); - return Status; + + return EFI_SUCCESS; } -- 2.16.2.windows.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
