target/file: Fix BUG() when CONFIG_DEBUG_SG=y and DIF protection enabled

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>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index fa54835f398b..3dcfc73528ec 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -274,7 +274,7 @@ static int fd_do_prot_rw(struct se_cmd *cmd, struct fd_prot *fd_prot,
                      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;
@@ -286,9 +286,10 @@ static int fd_do_prot_rw(struct se_cmd *cmd, struct fd_prot *fd_prot,
                                            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) {
@@ -318,7 +319,7 @@ static int fd_do_prot_rw(struct se_cmd *cmd, struct fd_prot *fd_prot,
 
         if (is_write || ret < 0) {
                 kfree(fd_prot->prot_sg);
-                vfree(fd_prot->prot_buf);
+                kfree(fd_prot->prot_buf);
         }
 
         return ret;
@@ -599,11 +600,11 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
                                                  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));
@@ -619,7 +620,7 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
                                                   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;
                         }
                 }
@@ -655,7 +656,7 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 
         if (ret < 0) {
                 kfree(fd_prot.prot_sg);
-                vfree(fd_prot.prot_buf);
+                kfree(fd_prot.prot_buf);
                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
         }