The patch titled
Subject: acpi_memhotplug.c: don't allow to eject the memory device if it is being used
has been added to the -mm tree. Its filename is
acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used.patch
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------------------------------------------------------
From: Wen Congyang <wency@xxxxxxxxxxxxxx>
Subject: acpi_memhotplug.c: don't allow to eject the memory device if it is being used
We eject the memory device even if it is in use. It is very dangerous,
and it will cause the kernel to panic.
Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: "Brown, Len" <len.brown@xxxxxxxxx>
Cc: Yasuaki ISIMATU <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/acpi_memhotplug.c | 38 +++++++++++++++++++++++++------
1 file changed, 31 insertions(+), 7 deletions(-)
diff -puN drivers/acpi/acpi_memhotplug.c~acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used drivers/acpi/acpi_memhotplug.c
--- a/drivers/acpi/acpi_memhotplug.c~acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used
+++ a/drivers/acpi/acpi_memhotplug.c
@@ -78,6 +78,7 @@ struct acpi_memory_info {
unsigned short caching; /* memory cache attribute */
unsigned short write_protect; /* memory read/write attribute */
unsigned int enabled:1;
+ unsigned int failed:1;
};
struct acpi_memory_device {
@@ -257,9 +258,23 @@ static int acpi_memory_enable_device(str
node = memory_add_physaddr_to_nid(info->start_addr);
result = add_memory(node, info->start_addr, info->length);
- if (result)
+
+ /*
+ * If the memory block has been used by the kernel, add_memory()
+ * returns -EEXIST. If add_memory() returns the other error, it
+ * means that this memory block is not used by the kernel.
+ */
+ if (result && result != -EEXIST) {
+ info->failed = 1;
continue;
- info->enabled = 1;
+ }
+
+ if (!result)
+ info->enabled = 1;
+ /*
+ * Add num_enable even if add_memory() returns -EEXIST, so the
+ * device is bound to this driver.
+ */
num_enabled++;
}
if (!num_enabled) {
@@ -323,11 +338,20 @@ static int acpi_memory_disable_device(st
* Note: Assume that this function returns zero on success
*/
list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
- if (info->enabled) {
- result = remove_memory(info->start_addr, info->length);
- if (result)
- return result;
- }
+ if (info->failed)
+ /* The kernel does not use this memory block */
+ continue;
+
+ if (!info->enabled)
+ /*
+ * The kernel uses this memory block, but it may be not
+ * managed by us.
+ */
+ return -EBUSY;
+
+ result = remove_memory(info->start_addr, info->length);
+ if (result)
+ return result;
list_del(&info->list);
kfree(info);
}
_
Subject: Subject: acpi_memhotplug.c: don't allow to eject the memory device if it is being used
Patches currently in -mm which might be from wency@xxxxxxxxxxxxxx are
mm-memory_hotplugc-release-memory-resources-if-hotadd_new_pgdat-fails.patch
acpi_memhotplugc-fix-memory-leak-when-memory-device-is-unbound-from-the-module-acpi_memhotplug.patch
acpi_memhotplugc-free-memory-device-if-acpi_memory_enable_device-failed.patch
acpi_memhotplugc-remove-memory-info-from-list-before-freeing-it.patch
acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used.patch
acpi_memhotplugc-bind-the-memory-device-when-the-driver-is-being-loaded.patch
acpi_memhotplugc-auto-bind-the-memory-device-which-is-hotplugged-before-the-driver-is-loaded.patch
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