The commit is pushed to "branch-rh7-3.10.0-957.21.3.vz7.106.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-957.21.3.vz7.106.7
------>
commit 3a44b99ce15ef953953e898b3cbab3e204fae3d3
Author: Kirill Tkhai <[email protected]>
Date: Tue Aug 6 13:25:11 2019 +0300
ploop: Check that nobody writes to ZERO_PAGE()
ploop juggles this aux_bio, reuses it from time to time,
so it's easy to make a mistake and to reuse a zero page.
Say, we use zero page in ploop_entry_nullify_req() after
fill_zero_bio(), and later PLOOP_E_RELOC_NULLIFY state
may become PLOOP_E_ENTRY, which is just generic state
of all requests.
For beter debug and detection of such the cases, add
the debug check to be safe against the above mistakes.
Signed-off-by: Kirill Tkhai <[email protected]>
---
drivers/block/ploop/dev.c | 5 ++++-
drivers/block/ploop/io_direct.c | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index 64d205e691ba..6fb95f0fadb6 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -1583,6 +1583,7 @@ static void bio_bcopy(struct bio *dst, struct bio *src,
struct ploop_device *plo
if (copy > PAGE_SIZE - poff)
copy = PAGE_SIZE - poff;
+ WARN_ON_ONCE(bv->bv_page == ZERO_PAGE(0));
ksrc = kmap_atomic(bv->bv_page);
memcpy(page_address(dst->bi_io_vec[didx].bv_page) + poff,
ksrc + bv->bv_offset + bv_off,
@@ -2768,9 +2769,11 @@ static void ploop_req_state_process(struct ploop_request
* preq)
break;
}
- for (i = 0; i < preq->aux_bio->bi_vcnt; i++)
+ for (i = 0; i < preq->aux_bio->bi_vcnt; i++) {
+
WARN_ON_ONCE(preq->aux_bio->bi_io_vec[i].bv_page == ZERO_PAGE(0));
memset(page_address(preq->aux_bio->bi_io_vec[i].bv_page),
0, PAGE_SIZE);
+ }
bio_list_for_each(b, &preq->bl) {
bio_bcopy(preq->aux_bio, b, plo);
diff --git a/drivers/block/ploop/io_direct.c b/drivers/block/ploop/io_direct.c
index abee1b2ae15c..6b4fd667ff71 100644
--- a/drivers/block/ploop/io_direct.c
+++ b/drivers/block/ploop/io_direct.c
@@ -348,6 +348,7 @@ static void bcopy_from_blist(struct page *page, int
dst_off, /* dst */
u8 *ksrc;
int copy = MIN(copy_len, biter->bv->bv_len - biter->off);
+ WARN_ON_ONCE(biter->bv->bv_page == ZERO_PAGE(0));
ksrc = kmap_atomic(biter->bv->bv_page);
memcpy(kdst + dst_off,
ksrc + biter->bv->bv_offset + biter->off,
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