memory hotplug: Refuse to add unaligned memory regions

PATCH In review Anton Blanchard 4 participants 4 messages Sep 14, 2011 – Nov 9, 2011

Subsystems (2)

Driver core Memory hot(un)plug

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Anton Blanchard

author

2011-09-14 20:26 UTC #0 lore raw

PATCH 1/1 memory hotplug: Refuse to add unaligned memory regions

The sysfs memory probe interface allows unaligned regions to be added:

# echo 0xffffff > /sys/devices/system/memory/probe

# cat /proc/iomem 
00ffffff-01fffffe : System RAM
01ffffff-02fffffe : System RAM
02ffffff-03fffffe : System RAM
03ffffff-04fffffe : System RAM
04ffffff-05fffffe : System RAM

Return -EINVAL instead of creating these bad regions.

Signed-off-by Anton Blanchard <[email protected]>

---

drivers/base/memory.c +4 -0

Index: linux-build/drivers/base/memory.c
===================================================================
@@ -380,9 +380,13 @@ memory_probe_store(struct class *class,
 	u64 phys_addr;
 	int nid;
 	int i, ret;
+	unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
 
 	phys_addr = simple_strtoull(buf, NULL, 0);
 
+	if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
+		return -EINVAL;
+
 	for (i = 0; i < sections_per_block; i++) {
 		nid = memory_add_physaddr_to_nid(phys_addr);
 		ret = add_memory(nid, phys_addr,

Greg KH

2011-09-15 06:46 UTC #1 lore raw

Quoted 13 lines · Anton Blanchard

The sysfs memory probe interface allows unaligned regions to be added:

# echo 0xffffff > /sys/devices/system/memory/probe

# cat /proc/iomem 
00ffffff-01fffffe : System RAM
01ffffff-02fffffe : System RAM
02ffffff-03fffffe : System RAM
03ffffff-04fffffe : System RAM
04ffffff-05fffffe : System RAM

Quoted 4 lines

Return -EINVAL instead of creating these bad regions.
Signed-off-by Anton Blanchard <[email protected]>
---

Is this something that should go into 3.1 and older kernels to properly handle this type of error?

greg k-h

Chen Gong

2011-11-09 07:28 UTC #3 lore raw

In reply to Anton Blanchard

Quoted 27 lines · Anton Blanchard

The sysfs memory probe interface allows unaligned regions to be added:
# echo 0xffffff>  /sys/devices/system/memory/probe
# cat /proc/iomem
00ffffff-01fffffe : System RAM
01ffffff-02fffffe : System RAM
02ffffff-03fffffe : System RAM
03ffffff-04fffffe : System RAM
04ffffff-05fffffe : System RAM
Return -EINVAL instead of creating these bad regions.
Signed-off-by Anton Blanchard<[email protected]>
---
Index: linux-build/drivers/base/memory.c
===================================================================
drivers/base/memory.c +1 -0
@@ -380,9 +380,13 @@ memory_probe_store(struct class *class,
  	u64 phys_addr;
  	int nid;
  	int i, ret;
+	unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;

drivers/base/memory.c memory_probe_store(struct class *class,

Quoted 10 lines

drivers/base/memory.c +3 -1

 
  	phys_addr = simple_strtoull(buf, NULL, 0);
 
+	if (phys_addr&  ((pages_per_block<<  PAGE_SHIFT) - 1))
+		return -EINVAL;
+
  	for (i = 0; i<  sections_per_block; i++) {
  		nid = memory_add_physaddr_to_nid(phys_addr);
  		ret = add_memory(nid, phys_addr,
--

what platform doese it affect? PowerPC or else?

As I know, on x86 platform it should not use this interface: *probe*, instead of acpi_hotplug_xxx. But PowerPC is RISC so how can you add such weird address for it? Maybe it is because PowerPC uses 16M as one section size and you assign a wrong address to it intentionally. The final result is as you show, isn't it?