On Wed, 20 Oct 2004, Andrew Cagney wrote:
Theodore A. Roth wrote:
Hi,
I just encountered a problem with using the "load" command with a remote
avr target. The first packet would be sent to the remote target and then
gdb would just give up with this error message:
(gdb) load
Loading section .text, size 0x1f8 lma 0x0
Sending packet: $M0,a:0c9446000c9463000c94#d7...Ack
Packet received: OK
Memory access error while loading section .text.
It looks like load_section_callback() in symfile.c is assuming that a
call to target_write_memory_partial() will set the err variable.
Unfortunately, that is not a valid assumption.
The attached patch got things working again, but this feels like a hack
to me since target_write_memory_partial() should really be setting err
to a sane value before returning.
Patch is against today's cvs mainline.
Here's the contract:
/* Make a single attempt at transfering LEN bytes. On a successful
transfer, the number of bytes actually transfered is returned and
ERR is set to 0. When a transfer fails, -1 is returned (the number
of bytes actually transfered is not defined) and ERR is set to a
non-zero error indication. */
So the bug is further down the target stack.
Both target_write_memory_partial() and target_read_memory_partial()
break that contract then:
int
target_write_memory_partial (CORE_ADDR memaddr, char *buf, int len, int *err)
{
if (target_xfer_partial_p ())
return target_xfer_partial (target_stack, TARGET_OBJECT_MEMORY, NULL,
NULL, buf, memaddr, len);
else
return target_xfer_memory_partial (memaddr, buf, len, 1, err);
}
If target_xfer_partial_p() returns true (which the avr port does), then
err is never set and the caller will see garbage if it didn't initialize
err.
Should the return value of the target_xfer_partial() call be checked, or
should err just be blindly see to zero?