patch "staging: erofs: fix to handle error path of erofs_vmap()" added to staging-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    staging: erofs: fix to handle error path of erofs_vmap()

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 8bce6dcede65139a087ff240127e3f3c01363eed Mon Sep 17 00:00:00 2001
From: Chao Yu <yuchao0@huawei.com>
Date: Mon, 11 Mar 2019 23:10:10 +0800
Subject: staging: erofs: fix to handle error path of erofs_vmap()

erofs_vmap() wrapped vmap() and vm_map_ram() to return virtual
continuous memory, but both of them can failed due to a lot of
reason, previously, erofs_vmap()'s callers didn't handle them,
which can potentially cause NULL pointer access, fix it.

Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
Fixes: 0d40d6e399c1 ("staging: erofs: add a generic z_erofs VLE decompressor")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/erofs/unzip_vle.c     | 4 ++++
 drivers/staging/erofs/unzip_vle_lz4.c | 7 +++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index 8715bc50e09c..c7b3b21123c1 100644
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -1029,6 +1029,10 @@ static int z_erofs_vle_unzip(struct super_block *sb,
 
 skip_allocpage:
 	vout = erofs_vmap(pages, nr_pages);
+	if (!vout) {
+		err = -ENOMEM;
+		goto out;
+	}
 
 	err = z_erofs_vle_unzip_vmap(compressed_pages,
 		clusterpages, vout, llen, work->pageofs, overlapped);
diff --git a/drivers/staging/erofs/unzip_vle_lz4.c b/drivers/staging/erofs/unzip_vle_lz4.c
index 48b263a2731a..0daac9b984a8 100644
--- a/drivers/staging/erofs/unzip_vle_lz4.c
+++ b/drivers/staging/erofs/unzip_vle_lz4.c
@@ -136,10 +136,13 @@ int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages,
 
 	nr_pages = DIV_ROUND_UP(outlen + pageofs, PAGE_SIZE);
 
-	if (clusterpages == 1)
+	if (clusterpages == 1) {
 		vin = kmap_atomic(compressed_pages[0]);
-	else
+	} else {
 		vin = erofs_vmap(compressed_pages, clusterpages);
+		if (!vin)
+			return -ENOMEM;
+	}
 
 	preempt_disable();
 	vout = erofs_pcpubuf[smp_processor_id()].data;
-- 
2.21.0