Karunakar,
Every Pool allocation has a header and a tail data structure that is outside of
the user visible data. Both these structures have signatures. The ASSERT you
are seeing is a bad signature in the header so that looks like a buffer
underflow. It could also be a use after free bug.
Head:
POOL_HEAD
Buffer:
User Data
Tail:
POOL_TAIL
Given the checks only happen on Free it is possible it could be a buffer
overflow on a buffer that has not yet been freed that runs into this buffer.
If you have a debugger dumping the memory before and after the buffer can some
times be useful. The pattern might give you some clues.
Thanks,
Andrew Fish
> On May 23, 2017, at 10:16 PM, Karunakar P <karunak...@amiindia.co.in> wrote:
>
> Hello All,
>
> The ASSERT happens in the following function
>
> /**
> Internal function to free a pool entry.
> Caller must have the memory lock held
>
> @param Buffer The allocated pool entry to free
> @param PoolType Pointer to pool type
>
> @retval EFI_INVALID_PARAMETER Buffer not valid
> @retval EFI_SUCCESS Buffer successfully freed.
>
> **/
> EFI_STATUS
> CoreFreePoolI (
> IN VOID *Buffer,
> OUT EFI_MEMORY_TYPE *PoolType OPTIONAL
> )
> {
> .
> .
> ASSERT(Buffer != NULL);
> //
> // Get the head & tail of the pool entry
> //
> Head = CR (Buffer, POOL_HEAD, Data, POOL_HEAD_SIGNATURE); // ASSERT
> happens here
> ASSERT(Head != NULL);
> .
> .
> }
>
> We are using NetworkPkg: SHA- ef810bc807188224a752ffbcf5e7f4b651291cee
>
> I think here I'm unable attach the files.
> You can find the attached screenshots in the following Bug571
> https://bugzilla.tianocore.org/show_bug.cgi?id=571
>
> Thanks,
> Karunakar
>
>
> -----Original Message-----
> From: Ye, Ting [mailto:ting...@intel.com]
> Sent: Wednesday, May 24, 2017 10:29 AM
> To: Karunakar P; edk2-devel@lists.01.org
> Subject: RE: Pressing ESC from "PXE windows Boot manager" causes ASSERT
>
> Hi Karunakar,
>
> Sorry I did not find your attached files. Would you please send them again?
> Besides that, do you mind telling us which code base are you using for PXE
> boot? Are you using some revision of EDKII main trunk or UDK release?
>
> Thanks,
> Ting
>
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of
> Karunakar P
> Sent: Wednesday, May 24, 2017 12:20 PM
> To: edk2-devel@lists.01.org
> Subject: [edk2] Pressing ESC from "PXE windows Boot manager" causes ASSERT
>
> Hi All,
>
> We have facing an issue with PXE boot.
> [Issue]
> When ESC is pressed from Windows Boot manager during PXE boot (IPv4 or IPv6)
> system Hangs with following ASSERT
>
> ASSERT [DxeCore] \MdeModulePkg\Core\Dxe\Mem\Pool.c : CR has Bad Signature
>
> [Reproduction Steps]
> 1. Perform UEFI PXEv4 or UEFI PXEv6 boot 2. It will start PXE boot over
> IPv4/6 and Downloads NBP file successfully.
> Attached the Screenshot for the same(ScreenShot1.jpg)
>
> It will Displays the info like "Press ENTER for network boot service"
> Attached Screensho(ScreenShot2.jpg)
>
> 3. Press ENTER and then press ESC immediately to see the Windows Boot Manager
> Menu
> It will list the available Operating Systems
> Attached the screenshot(ScreenShot3.png)
>
> 4. Press ESC to come back to Setup or next Boot option
>
> [Result]
> System hangs with ASSERT
>
> [Expected Result]
> On pressing ESC from Windows Boot Manager, it should come back to setup/Next
> boot option in boot order
>
> Note:
> We have PXE server configured in Windows Server 2012 R2.
>
> Please look into it.
>
>
> Thanks,
> karunakar
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