[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <13A253B3F9BEFE43B93C09CF75F63CAA81A8AB39BC@MNEXMB1.qlogic.org>
Date: Wed, 7 Mar 2012 13:40:21 -0600
From: Rajesh Borundia <rajesh.borundia@...gic.com>
To: santosh prasad nayak <santoshprasadnayak@...il.com>,
Sony Chacko <sony.chacko@...gic.com>
CC: netdev <netdev@...r.kernel.org>,
Dhananjay Phadke <dhananjay.phadke@...gic.com>,
"kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: RE: [PATCH] netxen: memory corruption by netxen_p3_get_mac_addr.
> -----Original Message-----
> From: santosh prasad nayak [mailto:santoshprasadnayak@...il.com]
> Sent: Sunday, March 04, 2012 2:48 PM
> To: Sony Chacko
> Cc: Rajesh Borundia; netdev; Dhananjay Phadke; kernel-
> janitors@...r.kernel.org
> Subject: Re: [PATCH] netxen: memory corruption by
> netxen_p3_get_mac_addr.
>
> I would like to drop this patch.
>
>
> Actually I was trying to simulate the code block by generating assembly
> code
> which looked like as shown below. But later I realized it does not
> fit with present scenario.
> Its for different scenario.
>
> -----------------------------------------------------------------------
> -------------------------------
> 80483cb: 83 ec 2c sub $0x2c,%esp
> 80483ce: 66 c7 44 24 1e e1 2e movw $0x2ee1,0x1e(%esp)
> 80483d5: 66 c7 44 24 1c e1 2e movw $0x2ee1,0x1c(%esp)
> 80483dc: 0f b7 44 24 1c movzwl 0x1c(%esp),%eax
> 80483e1: c1 e0 04 shl $0x4,%eax
> 80483e4: 88 44 24 1b mov %al,0x1b(%esp)
> 80483e8: 0f b6 5c 24 1b movzbl 0x1b(%esp),%ebx
> 80483ed: 0f b7 4c 24 1c movzwl 0x1c(%esp),%ecx
> 80483f2: 0f b7 54 24 1e movzwl 0x1e(%esp),%edx
> -----------------------------------------------------------------------
> -------------------------------------
>
>
>
> Following assembly code looks very near to present scenario.
> And there is no data loss .
>
> -----------------------------------------------------------------------
> ------------------------
> 804839a: 83 ec 10 sub $0x10,%esp
> 804839d: 66 c7 44 24 0e e1 2e movw $0x2ee1,0xe(%esp)
> 80483a4: 66 c7 44 24 0c e1 2e movw $0x2ee1,0xc(%esp)
> 80483ab: 0f b7 44 24 0c movzwl 0xc(%esp),%eax
> 80483b0: ba 00 00 00 00 mov $0x0,%edx
> 80483b5: 0f a4 c2 04 shld $0x4,%eax,%edx
> 80483b9: c1 e0 04 shl $0x4,%eax
> 80483bc: 89 04 24 mov %eax,(%esp)
> 80483bf: 89 54 24 04 mov %edx,0x4(%esp)
> 80483c3: b8 00 00 00 00 mov $0x0,%eax
> -----------------------------------------------------------------------
> ----------------------------
>
>
> Sorry for the inconvenience.
>
>
> Regarding endian issue:
> --------------------------------------
> Can Rajesh or Dhananjay comment on it ?
> Is "le64_to_cpu" there intentionally ??
>
Yes , le64_to_cpu is intentional the NXRD32/readl will swap the bytes and at lower address
we will have MSB. So while referencing it with byte array we need a extra swap.
Rajesh
> Regards
> santosh
>
>
> On Sun, Mar 4, 2012 at 12:05 AM, Dan Carpenter
> <dan.carpenter@...cle.com> wrote:
> > On Sat, Mar 03, 2012 at 10:31:27PM +0530, santosh nayak wrote:
> >> From: Santosh Nayak <santoshprasadnayak@...il.com>
> >>
> >> 'mac_hi' and 'mac_lo' are 32 bit unsinged int but we are modifing
> >> 64 bit of memory during mac calculation. To fix this issue define
> >> a local variable of 64 bit and do mac calculation.
> >>
> >
> > I'm not seeing any memory corruption. How do you figure?
> >
> >> Remove 'le64_to_cpu' to fix endian issue.
> >
> > I've add Dhananjay to the CC list to comment on the endian change.
> >
> > regards,
> > dan carpenter
> >
> >>
> >> Signed-off-by: Santosh Nayak <santoshprasadnayak@...il.com>
> >> ---
> >> drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c | 7 ++++---
> >> 1 files changed, 4 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c
> b/drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c
> >> index 0f81287..7ea930b 100644
> >> --- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c
> >> +++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c
> >> @@ -1069,7 +1069,8 @@ int netxen_get_flash_mac_addr(struct
> netxen_adapter *adapter, u64 *mac)
> >>
> >> int netxen_p3_get_mac_addr(struct netxen_adapter *adapter, u64
> *mac)
> >> {
> >> - uint32_t crbaddr, mac_hi, mac_lo;
> >> + uint32_t crbaddr;
> >> + u64 mac_hi, mac_lo;
> >> int pci_func = adapter->ahw.pci_func;
> >>
> >> crbaddr = CRB_MAC_BLOCK_START +
> >> @@ -1079,9 +1080,9 @@ int netxen_p3_get_mac_addr(struct
> netxen_adapter *adapter, u64 *mac)
> >> mac_hi = NXRD32(adapter, crbaddr+4);
> >>
> >> if (pci_func & 1)
> >> - *mac = le64_to_cpu((mac_lo >> 16) | ((u64)mac_hi <<
> 16));
> >> + *mac = (mac_lo >> 16) | (mac_hi << 16);
> >> else
> >> - *mac = le64_to_cpu((u64)mac_lo | ((u64)mac_hi << 32));
> >> + *mac = mac_lo | (mac_hi << 32);
> >>
> >> return 0;
> >> }
> >> --
> >> 1.7.4.4
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe kernel-
> janitors" in
> >> the body of a message to majordomo@...r.kernel.org
> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists