Commit 917db484dc6a "x86/boot: Fix kdump, cleanup aborted E820_PRAM
max_pfn manipulation" fixed up the broken manipulations of max_pfn in
the presence of E820_PRAM ranges. However, it also broke the
sanitize_e820_map() support for not merging E820_PRAM ranges.
Re-introduce the enabling to keep resource boundaries between
consecutive defined ranges. Otherwise, for example, an environment that
boots with memmap=2G!8G,2G!10G will end up with a single 4G /dev/pmem0
device instead of a /dev/pmem0 and /dev/pmem1 device 2G in size.

Cc: <>
Cc: Zhang Yi <>
Cc: Jeff Moyer <>
Cc: Ingo Molnar <>
Cc: Thomas Gleixner <>
Reported-by: Dave Chinner <>
Fixes: 917db484dc6a ("x86/boot: Fix kdump, cleanup aborted E820_PRAM max_pfn 
Signed-off-by: Dan Williams <>
 arch/x86/kernel/e820.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index b85fe5f91c3f..90e8dde3ec26 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -350,7 +350,7 @@ int __init sanitize_e820_map(struct e820entry *biosmap, int 
                 * continue building up new bios map based on this
                 * information
-               if (current_type != last_type) {
+               if (current_type != last_type || current_type == E820_PRAM) {
                        if (last_type != 0)      {
                                new_bios[new_bios_entry].size =
                                        change_point[chgidx]->addr - last_addr;

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