[PATCH 3.14 58/92] target/file: Fix BUG() when CONFIG_DEBUG_SG=y and DIF protection enabled

Greg Kroah-Hartman
2015-05-02T19:44:37Z

From: Akinobu Mita <akinobu.mita@gmail.com>

commit 38da0f49e8aa1649af397d53f88e163d0e60c058 upstream.

When CONFIG_DEBUG_SG=y and DIF protection support enabled, kernel
BUG()s are triggered due to the following two issues:

1) prot_sg is not initialized by sg_init_table().

When CONFIG_DEBUG_SG=y, scatterlist helpers check sg entry has a
correct magic value.

2) vmalloc'ed buffer is passed to sg_set_buf().

sg_set_buf() uses virt_to_page() to convert virtual address to struct
page, but it doesn't work with vmalloc address. vmalloc_to_page()
should be used instead. As prot_buf isn't usually too large, so
fix it by allocating prot_buf by kmalloc instead of vmalloc.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/target/target_core_file.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -273,7 +273,7 @@ static int fd_do_prot_rw(struct se_cmd *
se_dev->prot_length;

if (!is_write) {
- fd_prot->prot_buf = vzalloc(prot_size);
+ fd_prot->prot_buf = kzalloc(prot_size, GFP_KERNEL);
if (!fd_prot->prot_buf) {
pr_err("Unable to allocate fd_prot->prot_buf\n");
return -ENOMEM;
@@ -285,9 +285,10 @@ static int fd_do_prot_rw(struct se_cmd *
fd_prot->prot_sg_nents, GFP_KERNEL);
if (!fd_prot->prot_sg) {
pr_err("Unable to allocate fd_prot->prot_sg\n");
- vfree(fd_prot->prot_buf);
+ kfree(fd_prot->prot_buf);
return -ENOMEM;
}
+ sg_init_table(fd_prot->prot_sg, fd_prot->prot_sg_nents);
size = prot_size;

for_each_sg(fd_prot->prot_sg, sg, fd_prot->prot_sg_nents, i) {
@@ -317,7 +318,7 @@ static int fd_do_prot_rw(struct se_cmd *

if (is_write || ret < 0) {
kfree(fd_prot->prot_sg);
- vfree(fd_prot->prot_buf);
+ kfree(fd_prot->prot_buf);
}

return ret;
@@ -652,11 +653,11 @@ fd_execute_rw(struct se_cmd *cmd, struct
0, fd_prot.prot_sg, 0);
if (rc) {
kfree(fd_prot.prot_sg);
- vfree(fd_prot.prot_buf);
+ kfree(fd_prot.prot_buf);
return rc;
}
kfree(fd_prot.prot_sg);
- vfree(fd_prot.prot_buf);
+ kfree(fd_prot.prot_buf);
}
} else {
memset(&fd_prot, 0, sizeof(struct fd_prot));
@@ -672,7 +673,7 @@ fd_execute_rw(struct se_cmd *cmd, struct
0, fd_prot.prot_sg, 0);
if (rc) {
kfree(fd_prot.prot_sg);
- vfree(fd_prot.prot_buf);
+ kfree(fd_prot.prot_buf);
return rc;
}
}
@@ -703,7 +704,7 @@ fd_execute_rw(struct se_cmd *cmd, struct

if (ret < 0) {
kfree(fd_prot.prot_sg);
- vfree(fd_prot.prot_buf);
+ kfree(fd_prot.prot_buf);
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}