Some sub-1MB memory regions may be reserved by EFI boot services, and the
memory regions will be released later in the efi_free_boot_services().
Currently, always reserve all sub-1MB memory regions when the crashkernel
option is specified, but unfortunately EFI boot services may have already
reserved some sub-1MB memory regions before the crash_reserve_low_1M() is
called, which makes that the crash_reserve_low_1M() only own the
remaining sub-1MB memory regions, not all sub-1MB memory regions, because,
subsequently EFI boot services will free its own sub-1MB memory regions.
Eventually, DMA will be able to allocate memory from the sub-1MB area and
cause the following error:
crash> kmem -s |grep invalid
kmem: dma-kmalloc-512: slab: ffffd52c40001900 invalid freepointer: ffff9403c0067300
kmem: dma-kmalloc-512: slab: ffffd52c40001900 invalid freepointer: ffff9403c0067300
crash> vtop ffff9403c0067300
VIRTUAL PHYSICAL
ffff9403c0067300 67300 --->The physical address falls into this range [0x0000000000063000-0x000000000008efff]
kernel debugging log:
...
[ 0.008927] memblock_reserve: [0x0000000000010000-0x0000000000013fff] efi_reserve_boot_services+0x85/0xd0
[ 0.008930] memblock_reserve: [0x0000000000063000-0x000000000008efff] efi_reserve_boot_services+0x85/0xd0
...
[ 0.009425] memblock_reserve: [0x0000000000000000-0x00000000000fffff] crash_reserve_low_1M+0x2c/0x49
...
[ 0.010586] Zone ranges:
[ 0.010587] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.010589] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.010591] Normal [mem 0x0000000100000000-0x0000000c7fffffff]
[ 0.010593] Device empty
...
[ 8.814894] __memblock_free_late: [0x0000000000063000-0x000000000008efff] efi_free_boot_services+0x14b/0x23b
[ 8.815793] __memblock_free_late: [0x0000000000010000-0x0000000000013fff] efi_free_boot_services+0x14b/0x23b
Do not release sub-1MB memory regions even though they are reserved by
EFI boot services, so that always reserve all sub-1MB memory regions when
the crashkernel option is specified.
Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
---
arch/x86/platform/efi/quirks.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 67d93a243c35..637f932c4fd4 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -18,6 +18,7 @@
#include <asm/cpu_device_id.h>
#include <asm/realmode.h>
#include <asm/reboot.h>
+#include <asm/cmdline.h>
#define EFI_MIN_RESERVE 5120
@@ -303,6 +304,19 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
*/
static __init bool can_free_region(u64 start, u64 size)
{
+ /*
+ * Some sub-1MB memory regions may be reserved by EFI boot
+ * services, and these memory regions will be released later
+ * in the efi_free_boot_services().
+ *
+ * Do not release sub-1MB memory regions even though they are
+ * reserved by EFI boot services, because, always reserve all
+ * sub-1MB memory when the crashkernel option is specified.
+ */
+ if (cmdline_find_option(boot_command_line, "crashkernel", NULL, 0) > 0
+ && (start + size < (1<<20)))
+ return false;
+
if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
return false;
--
2.17.1
