diff options
| author | Brian King <brking@linux.vnet.ibm.com> | 2015-07-14 18:41:31 +0200 |
|---|---|---|
| committer | James Bottomley <JBottomley@Odin.com> | 2015-07-30 19:38:00 +0200 |
| commit | bb7c54339e6a10ecce5c4961adf5e75b3cf0af30 (patch) | |
| tree | 415cedd069567d7be55d8da522207069cff4e634 /drivers/scsi/ipr.c | |
| parent | ipr: Fix locking for unit attention handling (diff) | |
| download | linux-bb7c54339e6a10ecce5c4961adf5e75b3cf0af30.tar.xz linux-bb7c54339e6a10ecce5c4961adf5e75b3cf0af30.zip | |
ipr: Fix incorrect trace indexing
When ipr's internal driver trace was changed to an atomic, a signed/unsigned
bug slipped in which results in us indexing backwards in our memory buffer
writing on memory that does not belong to us. This patch fixes this by removing
the modulo and instead just mask off the low bits.
Cc: <stable@vger.kernel.org>
Tested-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Diffstat (limited to 'drivers/scsi/ipr.c')
| -rw-r--r-- | drivers/scsi/ipr.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c index 486ffaf5109a..7ae9cd743eb2 100644 --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -599,9 +599,10 @@ static void ipr_trc_hook(struct ipr_cmnd *ipr_cmd, { struct ipr_trace_entry *trace_entry; struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg; + unsigned int trace_index; - trace_entry = &ioa_cfg->trace[atomic_add_return - (1, &ioa_cfg->trace_index)%IPR_NUM_TRACE_ENTRIES]; + trace_index = atomic_add_return(1, &ioa_cfg->trace_index) & IPR_TRACE_INDEX_MASK; + trace_entry = &ioa_cfg->trace[trace_index]; trace_entry->time = jiffies; trace_entry->op_code = ipr_cmd->ioarcb.cmd_pkt.cdb[0]; trace_entry->type = type; |