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 fixes this problem by using sysfs_streq() to compare the
whole string.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reported-by: Hu Tao <hutao@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed