To Damien,

Please test this, I think this maybe helpful.


Thanks,

BRs



On 2017年07月11日 16:05, [email protected] wrote:
From: Xiubo Li <[email protected]>

For all the entries allocated from the ring cmd area, the memory
is something like the stack, which will reserve the old data, so
the entry->req.iov_bidi_cnt maybe none zero.

To fix this, just memset all the entry memory before using it, and
also to be more readable we adjust the bidi code.

Fixed: fe25cc34795(tcmu: Recalculate the tcmu_cmd size to save cmd area
                memories)
Reported-by: Bryant G. Ly <[email protected]>
Signed-off-by: Xiubo Li <[email protected]>
---
  drivers/target/target_core_user.c | 5 +++--
  1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_user.c 
b/drivers/target/target_core_user.c
index 2f1fa92..be62c86 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -840,6 +840,7 @@ static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd 
*tcmu_cmd,
        }
entry = (void *) mb + CMDR_OFF + cmd_head;
+       memset(entry, 0, command_size);
        tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
        entry->hdr.cmd_id = tcmu_cmd->cmd_id;
        entry->hdr.kflags = 0;
@@ -865,8 +866,8 @@ static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd 
*tcmu_cmd,
        entry->req.iov_dif_cnt = 0;
/* Handle BIDI commands */
+       iov_cnt = 0;
        if (se_cmd->se_cmd_flags & SCF_BIDI) {
-               iov_cnt = 0;
                iov++;
                ret = scatter_data_area(udev, tcmu_cmd,
                                        se_cmd->t_bidi_data_sg,
@@ -879,8 +880,8 @@ static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd 
*tcmu_cmd,
                        pr_err("tcmu: alloc and scatter bidi data failed\n");
                        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                }
-               entry->req.iov_bidi_cnt = iov_cnt;
        }
+       entry->req.iov_bidi_cnt = iov_cnt;
/*
         * Recalaulate the command's base size and size according



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