Messages in this thread | | | Subject | [PATCH v2 0/4] efi: Fix handling of multiple efi_fake_mem= entries | From | Dan Williams <> | Date | Tue, 31 Dec 2019 14:04:17 -0800 |
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Changes since v1 [1]: - Add support for garbage collecting idle efi_memmap_alloc() allocations
- As Dave noticed the same problem of calling efi_memmap_split_count() multiple times with the old map also applies to efi_memmap_insert(). Update efi_fake_memmap() to invoke efi_memmap_install() after every efi_memmap_insert() call.
[1]: https://lore.kernel.org/r/157773590338.4153451.5898675419563883883.stgit@dwillia2-desk3.amr.corp.intel.com/
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Copied from patch4:
Dave noticed that when specifying multiple efi_fake_mem= entries only the last entry was successfully being reflected in the efi memory map. This is due to the fact that the efi_memmap_insert() is being called multiple times, but on successive invocations the insertion should be applied to the last new memmap rather than the original map at efi_fake_memmap() entry.
Rework efi_fake_memmap() to install the new memory map after each efi_fake_mem= entry is parsed.
This also fixes an issue in efi_fake_memmap() that caused it to litter emtpy entries into the end of the efi memory map. The empty entry causes efi_memmap_insert() to attempt more memmap splits / copies than efi_memmap_split_count() accounted for when sizing the new map.
BUG: unable to handle page fault for address: ffffffffff281000 [..] RIP: 0010:efi_memmap_insert+0x11d/0x191 [..] Call Trace: ? bgrt_init+0xbe/0xbe ? efi_arch_mem_reserve+0x1cb/0x228 ? acpi_parse_bgrt+0xa/0xd ? acpi_table_parse+0x86/0xb8 ? acpi_boot_init+0x494/0x4e3 ? acpi_parse_x2apic+0x87/0x87 ? setup_acpi_sci+0xa2/0xa2 ? setup_arch+0x8db/0x9e1 ? start_kernel+0x6a/0x547 ? secondary_startup_64+0xb6/0xc0
Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot services data to fix kexec breakage" is listed in Fixes: since it introduces more occurrences where efi_memmap_insert() is invoked after an efi_fake_mem= configuration has been parsed. Previously the side effects of vestigial empty entries were benign, but with commit af1648984828 that follow-on efi_memmap_insert() invocation triggers the above crash signature.
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Dan Williams (4): efi: Add a flags parameter to efi_memory_map efi: Add tracking for dynamically allocated memmaps efi: Fix efi_memmap_alloc() leaks efi: Fix handling of multiple efi_fake_mem= entries
arch/x86/platform/efi/efi.c | 2 + arch/x86/platform/efi/quirks.c | 11 ++++--- drivers/firmware/efi/fake_mem.c | 37 +++++++++++++------------ drivers/firmware/efi/memmap.c | 58 ++++++++++++++++++++++++++++++--------- include/linux/efi.h | 13 +++++++-- 5 files changed, 81 insertions(+), 40 deletions(-)
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