>On Tue, 6 Nov 2012 18:36:33 +0800 majianpeng <majianpeng@xxxxxxxxx> wrote:
>
>> >On Tue, 6 Nov 2012 17:13:00 +0800 majianpeng <majianpeng@xxxxxxxxx> wrote:
>> >
>> >> If read_seqretry returned true and bbp was changed, it will write
>> >> invalid address which can cause some serious problem.
>> >>
>> >> This bug was introduced by commit v3.0-rc7-130-g2699b67.
>> >> So fix is suitable for 3.0.y thru 3.6.y.
>> >>
>> >> Reported-by: zhuwenfeng@xxxxxxxxxxx
>> >> Tested-by: zhuwenfeng@xxxxxxxxxxx
>> >> Cc: stable@xxxxxxxxxxxxxxx
>> >> Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
>> >> ---
>> >> drivers/md/md.c | 4 ++--
>> >> 1 file changed, 2 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/drivers/md/md.c b/drivers/md/md.c
>> >> index 9ab768a..d63aa78 100644
>> >> --- a/drivers/md/md.c
>> >> +++ b/drivers/md/md.c
>> >> @@ -1805,15 +1805,15 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
>> >> md_error(mddev, rdev);
>> >> else {
>> >> struct badblocks *bb = &rdev->badblocks;
>> >> - u64 *bbp = (u64 *)page_address(rdev->bb_page);
>> >> u64 *p = bb->page;
>> >> sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
>> >> if (bb->changed) {
>> >> unsigned seq;
>> >> + u64 *bbp;
>> >>
>> >> retry:
>> >> + bbp = (u64 *)page_address(rdev->bb_page);
>> >> seq = read_seqbegin(&bb->lock);
>> >> -
>> >> memset(bbp, 0xff, PAGE_SIZE);
>> >>
>> >> for (i = 0 ; i < bb->count ; i++) {
>> >
>> >
>> >No.
>> >The contents of the page might change, but it is always the same page, so it
>> >always has the same address, so "bbp" is guaranteed to be stable.
>> >
>> >NeilBrown
>> >
>> Is my understand wrong?
>> >u64 *bbp = (u64 *)page_address(rdev->bb_page);
>> > u64 *p = bb->page;
>> > sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
>> > if (bb->changed) {
>> > unsigned seq;
>>
>> >retry:
>> > seq = read_seqbegin(&bb->lock);
>>
>> > memset(bbp, 0xff, PAGE_SIZE);
>>
>> > for (i = 0 ; i < bb->count ; i++) {
>> > u64 internal_bb = *p++;
>> > u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
>> > | BB_LEN(internal_bb));
>> > *bbp++ = cpu_to_le64(store_bb);
>> I think bbp will be changed. Is ok?
>
>
My patch missed one parameter:
>> > u64 internal_bb = *p++;
So the code should be:
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9ab768a..1f86c48 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1817,10 +1817,10 @@ retry:
memset(bbp, 0xff, PAGE_SIZE);
for (i = 0 ; i < bb->count ; i++) {
- u64 internal_bb = *p++;
+ u64 internal_bb = p[i];
u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
| BB_LEN(internal_bb));
- *bbp++ = cpu_to_le64(store_bb);
+ bbp[i] = cpu_to_le64(store_bb);
}
bb->changed = 0;
if (read_seqretry(&bb->lock, seq))
I think this is your first wanted!?韬{.n?????%??檩??w?{.n???{炳盯w???塄}?财??j:+v?? ? ???2??璀??摺?囤??z夸z罐?+?????w棹f
