Subject: + mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block.patch added to -mm tree
To: tangchen@xxxxxxxxxxxxxx,gregkh@xxxxxxxxxxxxxxxxxxx,guz.fnst@xxxxxxxxxxxxxx,hutao@xxxxxxxxxxxxxx,isimatu.yasuaki@xxxxxxxxxxxxxx,laijs@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 12 Jun 2014 12:28:34 -0700
The patch titled
Subject: mem-hotplug: avoid illegal state prefixed with legal state when changing state of memory_block
has been added to the -mm tree. Its filename is
mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block.patch
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------------------------------------------------------
From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Subject: mem-hotplug: avoid illegal state prefixed with legal state when changing state of memory_block
We use the following command to online a memory_block:
echo online|online_kernel|online_movable > /sys/devices/system/memory/memoryXXX/state
But, if we do the following:
echo online_fhsjkghfkd > /sys/devices/system/memory/memoryXXX/state
the block will also be onlined.
This is because the following code in store_mem_state() does not compare
the whole string, but only the prefix of the string.
store_mem_state()
{
......
328 if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
Here, only compare the first 13 letters of the string. If we give "online_kernelXXXXXX",
it will be recognized as online_kernel, which is incorrect.
329 online_type = ONLINE_KERNEL;
330 else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
We have the same problem here,
331 online_type = ONLINE_MOVABLE;
332 else if (!strncmp(buf, "online", min_t(int, count, 6)))
here,
(Here is more problematic. If we give online_movalbe, which is a typo of online_movable,
it will be recognized as online without noticing the author.)
333 online_type = ONLINE_KEEP;
334 else if (!strncmp(buf, "offline", min_t(int, count, 7)))
and here.
335 online_type = -1;
336 else {
337 ret = -EINVAL;
338 goto err;
339 }
......
}
This patch fix this problem by using sysfs_streq() to compare the whole string.
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Reported-by: Hu Tao <hutao@xxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/memory.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN drivers/base/memory.c~mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block drivers/base/memory.c
--- a/drivers/base/memory.c~mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block
+++ a/drivers/base/memory.c
@@ -315,13 +315,13 @@ store_mem_state(struct device *dev,
if (ret)
return ret;
- if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
+ if (sysfs_streq(buf, "online_kernel"))
online_type = ONLINE_KERNEL;
- else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
+ else if (sysfs_streq(buf, "online_movable"))
online_type = ONLINE_MOVABLE;
- else if (!strncmp(buf, "online", min_t(int, count, 6)))
+ else if (sysfs_streq(buf, "online"))
online_type = ONLINE_KEEP;
- else if (!strncmp(buf, "offline", min_t(int, count, 7)))
+ else if (sysfs_streq(buf, "offline"))
online_type = -1;
else {
ret = -EINVAL;
_
Patches currently in -mm which might be from tangchen@xxxxxxxxxxxxxx are
origin.patch
include-linux-memblockh-add-__init-to-memblock_set_bottom_up.patch
mem-hotplug-avoid-illegal-state-prefixed-with-legal-state-when-changing-state-of-memory_block.patch
mem-hotplug-introduce-mmop_offline-to-replace-the-hard-coding-1.patch
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