* + zram-do-not-use-copy_page-with-non-page-alinged-address.patch added to -mm tree
@ 2017-04-13 20:29 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2017-04-13 20:29 UTC (permalink / raw)
To: minchan, sergey.senozhatsky, stable, mm-commits
The patch titled
Subject: zram: do not use copy_page with non-page aligned address
has been added to the -mm tree. Its filename is
zram-do-not-use-copy_page-with-non-page-alinged-address.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-do-not-use-copy_page-with-non-page-alinged-address.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-do-not-use-copy_page-with-non-page-alinged-address.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Minchan Kim <minchan@kernel.org>
Subject: zram: do not use copy_page with non-page aligned address
The copy_page is optimized memcpy for page-alinged address. If it is used
with non-page aligned address, it can corrupt memory which means system
corruption. With zram, it can happen with
1. 64K architecture
2. partial IO
3. slub debug
Partial IO need to allocate a page and zram allocates it via kmalloc.
With slub debug, kmalloc(PAGE_SIZE) doesn't return page-size aligned
address. And finally, copy_page(mem, cmem) corrupts memory.
So, this patch changes it to memcpy.
Acutaully, we don't need to change zram_bvec_write part because zsmalloc
returns page-aligned address in case of PAGE_SIZE class but it's not good
to rely on the internal of zsmalloc.
Note:
When this patch is merged to stable, clear_page should be fixed, too.
Unfortunately, recent zram removes it by "same page merge" feature
so it's hard to backport this patch to -stable tree.
I will handle it when I receive the mail from stable tree maintainer to
merge this patch to backport.
Fixes: 42e99bd ("zram: optimize memory operations with clear_page()/copy_page()")
Link: http://lkml.kernel.org/r/1492042622-12074-2-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/block/zram/zram_drv.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN drivers/block/zram/zram_drv.c~zram-do-not-use-copy_page-with-non-page-alinged-address drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-do-not-use-copy_page-with-non-page-alinged-address
+++ a/drivers/block/zram/zram_drv.c
@@ -523,7 +523,7 @@ static int zram_decompress_page(struct z
cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
if (size == PAGE_SIZE) {
- copy_page(mem, cmem);
+ memcpy(mem, cmem, PAGE_SIZE);
} else {
struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
@@ -717,7 +717,7 @@ compress_again:
if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
src = kmap_atomic(page);
- copy_page(cmem, src);
+ memcpy(cmem, src, PAGE_SIZE);
kunmap_atomic(src);
} else {
memcpy(cmem, src, clen);
_
Patches currently in -mm which might be from minchan@kernel.org are
zram-fix-operator-precedence-to-get-offset.patch
zram-do-not-use-copy_page-with-non-page-alinged-address.patch
zsmalloc-expand-class-bit.patch
mm-reclaim-madv_free-pages-fix.patch
mm-fix-lazyfree-bug-on-check-in-try_to_unmap_one.patch
mm-fix-lazyfree-bug-on-check-in-try_to_unmap_one-fix.patch
mm-do-not-use-double-negation-for-testing-page-flags.patch
mm-remove-unncessary-ret-in-page_referenced.patch
mm-remove-swap_dirty-in-ttu.patch
mm-remove-swap_mlock-check-for-swap_success-in-ttu.patch
mm-make-the-try_to_munlock-void-function.patch
mm-make-the-try_to_munlock-void-function-fix.patch
mm-remove-swap_mlock-in-ttu.patch
mm-remove-swap_again-in-ttu.patch
mm-make-ttus-return-boolean.patch
mm-make-rmap_walk-void-function.patch
mm-make-rmap_one-boolean-function.patch
mm-remove-swap_.patch
mm-remove-swap_-fix.patch
zram-handle-multiple-pages-attached-bios-bvec.patch
zram-partial-io-refactoring.patch
zram-use-zram_slot_lock-instead-of-raw-bit_spin_lock-op.patch
zram-remove-zram_meta-structure.patch
zram-introduce-zram-data-accessor.patch
zram-use-zram_free_page-instead-of-open-coded.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2017-04-13 20:29 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-04-13 20:29 + zram-do-not-use-copy_page-with-non-page-alinged-address.patch added to -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.