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authorSeth Jennings <sjennings@variantweb.net>2015-12-11 13:40:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-12-12 10:15:34 -0800
commit26bbe7ef6d5cdc7ec08cba6d433fca4060f258f3 (patch)
tree13337f2be30164b30f22eea832c04c40a90781ad
parent267a4c76bbdb950688d3aeb020976c2918064584 (diff)
downloadlinux-linaro-stable-26bbe7ef6d5cdc7ec08cba6d433fca4060f258f3.tar.gz
drivers/base/memory.c: prohibit offlining of memory blocks with missing sections
Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems") and 982792c782ef ("x86, mm: probe memory block size for generic x86 64bit") introduced large block sizes for x86. This made it possible to have multiple sections per memory block where previously, there was a only every one section per block. Since blocks consist of contiguous ranges of section, there can be holes in the blocks where sections are not present. If one attempts to offline such a block, a crash occurs since the code is not designed to deal with this. This patch is a quick fix to gaurd against the crash by not allowing blocks with non-present sections to be offlined. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=107781 Signed-off-by: Seth Jennings <sjennings@variantweb.net> Reported-by: Andrew Banman <abanman@sgi.com> Cc: Daniel J Blueman <daniel@numascale.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Greg KH <greg@kroah.com> Cc: Russ Anderson <rja@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/base/memory.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 2804aed3f416..25425d3f2575 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -303,6 +303,10 @@ static int memory_subsys_offline(struct device *dev)
if (mem->state == MEM_OFFLINE)
return 0;
+ /* Can't offline block with non-present sections */
+ if (mem->section_count != sections_per_block)
+ return -EINVAL;
+
return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
}