Re: [PATCH] Revert "scsi: qla2xxx: Fix memcpy() field-spanning write issue"

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

On 9/25/25 16:18, John Meneghini wrote:
> On 9/25/25 9:38 AM, Gustavo A. R. Silva wrote:
>> On 9/25/25 15:07, John Meneghini wrote:
>>> This reverts commit 6f4b10226b6b1e7d1ff3cdb006cf0f6da6eed71e.
>>>
>>> We've been testing this patch and it turns out there is a significant
>>> bug here. This leaks memory and causes a driver hang.
>>>
>>> Link:
>>> https://lore.kernel.org/linux-scsi/yq1zfajqpec.fsf@ca-mkp.ca.oracle.com/
>>
>> Thanks for the report. I wonder if you have any logs or something I could
>> look at to figure out what's going on.
> 
> 
> We have a fix already.  Chris and Bryan figured it out.
> 
>> Bryan,
>>
>> Could you please share how this patch[1] was tested?
> 
> Bryan, please reply with bug fix patch you emailed me yesterday as an RFC patch.
> 
> Gustavo, this patch is being tested as a part of our FPIN LI changes. To run this code you need a Brocade switch and a whole lot of hardware.
> 
> You can see a example test plan here: https://bugzilla.kernel.org/attachment.cgi?id=308368&action=view
> 
> I am about to submit a version 10 patch series for these changes and I will include a new/fixed version of your patch in that series.

Awesome, thank you!

I was in the process of writing the following (draft) patch, which is much
less intrusive than the other one:

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index cb95b7b12051..1b000709ccd8 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -4890,9 +4890,10 @@ struct purex_item {
                              struct purex_item *pkt);
         atomic_t in_use;
         uint16_t size;
-       struct {
-               uint8_t iocb[64];
-       } iocb;
+       union {
+               uint8_t min_iocb[QLA_DEFAULT_PAYLOAD_SIZE];
+               DECLARE_FLEX_ARRAY(uint8_t, iocb);
+       };
  };

  #include "qla_edif.h"
@@ -5101,7 +5102,6 @@ typedef struct scsi_qla_host {
                 struct list_head head;
                 spinlock_t lock;
         } purex_list;
-       struct purex_item default_item;

         struct name_list_extended gnl;
         /* Count of active session/fcport */
@@ -5130,6 +5130,9 @@ typedef struct scsi_qla_host {
  #define DPORT_DIAG_IN_PROGRESS                 BIT_0
  #define DPORT_DIAG_CHIP_RESET_IN_PROGRESS      BIT_1
         uint16_t dport_status;
+
+       /* Must be last --ends in a flexible-array member. */
+       struct purex_item default_item;
  } scsi_qla_host_t;

  struct qla27xx_image_status {
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index c4c6b5c6658c..a342e137a53a 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1137,7 +1137,7 @@ static struct purex_item
         if (!item)
                 return item;

-       memcpy(&item->iocb, pkt, sizeof(item->iocb));
+       memcpy(&item->iocb, pkt, QLA_DEFAULT_PAYLOAD_SIZE);
         return item;
  }

diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
index 316594aa40cc..065f9bcca26f 100644
--- a/drivers/scsi/qla2xxx/qla_nvme.c
+++ b/drivers/scsi/qla2xxx/qla_nvme.c
@@ -1308,7 +1308,7 @@ void qla2xxx_process_purls_iocb(void **pkt, struct rsp_que **rsp)

         ql_dbg(ql_dbg_unsol, vha, 0x2121,
                "PURLS OP[%01x] size %d xchg addr 0x%x portid %06x\n",
-              item->iocb.iocb[3], item->size, uctx->exchange_address,
+              item->iocb[3], item->size, uctx->exchange_address,
                fcport->d_id.b24);
         /* +48    0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
          * ----- -----------------------------------------------


But if you already figured it out, that's great. :)

Thanks
-Gustavo

> /John
> 
>> Thanks
>> -Gustavo
>>
>> [1] https://lore.kernel.org/linux-scsi/20250813200744.17975-10-bgurney@redhat.com/
>>
>