[v3,2/3] gdbserver: Prevent stale/random values in register cache
Commit Message
When fetch_inferior_registers does not update all registers, this
patch assures that no stale register values remain in the register
cache. On Linux platforms using the regsets interface, when one of
the ptrace calls used for fetching the register values returns an
error, this patch also avoids copying the random data returned from
ptrace into the register cache. All unfetched registers are marked
"unavailable" instead.
gdb/gdbserver/ChangeLog:
* linux-low.c (regsets_fetch_inferior_registers): Do not invoke
the regset's store function when ptrace returned an error.
* regcache.c (get_thread_regcache): Invalidate register cache
before fetching inferior's registers.
---
gdb/gdbserver/linux-low.c | 11 ++++++-----
gdb/gdbserver/regcache.c | 5 +++++
2 files changed, 11 insertions(+), 5 deletions(-)
@@ -4255,8 +4255,6 @@ regsets_fetch_inferior_registers (struct regsets_info *regsets_info,
/* If we get EIO on a regset, do not try it again for
this process mode. */
disable_regset (regsets_info, regset);
- free (buf);
- continue;
}
else
{
@@ -4266,9 +4264,12 @@ regsets_fetch_inferior_registers (struct regsets_info *regsets_info,
perror (s);
}
}
- else if (regset->type == GENERAL_REGS)
- saw_general_regs = 1;
- regset->store_function (regcache, buf);
+ else
+ {
+ if (regset->type == GENERAL_REGS)
+ saw_general_regs = 1;
+ regset->store_function (regcache, buf);
+ }
free (buf);
}
if (saw_general_regs)
@@ -52,6 +52,11 @@ get_thread_regcache (struct thread_info *thread, int fetch)
struct thread_info *saved_thread = current_thread;
current_thread = thread;
+#ifndef IN_PROCESS_AGENT
+ /* Invalidate all registers, to prevent stale left-overs. */
+ memset (regcache->register_status, REG_UNAVAILABLE,
+ regcache->tdesc->num_registers);
+#endif
fetch_inferior_registers (regcache, -1);
current_thread = saved_thread;
regcache->registers_valid = 1;