[5/8] gdbserver/linux-x86: make is_64bit_tdesc accept thread as a parameter
Commit Message
ps_get_thread_area receives as a parameter the lwpid it must work on.
It then calls is_64bit_tdesc, which uses the current_thread as the
thread to work on. However, it is not said that both are the same.
This became a problem when working in a following patch that pmakes
find_one_thread switch to a process but to no thread (current_thread ==
nullptr). When libthread_db needed to get the thread area,
is_64bit_tdesc would try to get the regcache of a nullptr thread.
Fix that by making is_64bit_tdesc accept the thread to work on as a
parameter. Find the right thread from the context, when possible (when
we know the lwpid to work on). Otherwise, pass "current_thread", to
retain the existing behavior.
Change-Id: I44394d6be92392fa28de71982fd04517ce8a3007
---
gdbserver/linux-x86-low.cc | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
Comments
Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
> ps_get_thread_area receives as a parameter the lwpid it must work on.
> It then calls is_64bit_tdesc, which uses the current_thread as the
> thread to work on. However, it is not said that both are the same.
>
> This became a problem when working in a following patch that pmakes
s/pmakes/makes/
> find_one_thread switch to a process but to no thread (current_thread ==
> nullptr). When libthread_db needed to get the thread area,
> is_64bit_tdesc would try to get the regcache of a nullptr thread.
>
> Fix that by making is_64bit_tdesc accept the thread to work on as a
> parameter. Find the right thread from the context, when possible (when
> we know the lwpid to work on). Otherwise, pass "current_thread", to
> retain the existing behavior.
>
> Change-Id: I44394d6be92392fa28de71982fd04517ce8a3007
> ---
> gdbserver/linux-x86-low.cc | 27 +++++++++++++++------------
> 1 file changed, 15 insertions(+), 12 deletions(-)
>
> diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
> index d2b55f6f0d2..c98a7a461fe 100644
> --- a/gdbserver/linux-x86-low.cc
> +++ b/gdbserver/linux-x86-low.cc
> @@ -275,9 +275,9 @@ static /*const*/ int i386_regmap[] =
> per the tdesc. */
>
> static int
> -is_64bit_tdesc (void)
> +is_64bit_tdesc (thread_info *thread)
I think the comment for this function needs updating, the reference to
"current inferior" probably needs to be replaced with THREAD.
With those changes, LGTM.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Thanks,
Andrew
> {
> - struct regcache *regcache = get_thread_regcache (current_thread, 0);
> + struct regcache *regcache = get_thread_regcache (thread, 0);
>
> return register_size (regcache->tdesc, 0) == 8;
> }
> @@ -292,7 +292,9 @@ ps_get_thread_area (struct ps_prochandle *ph,
> lwpid_t lwpid, int idx, void **base)
> {
> #ifdef __x86_64__
> - int use_64bit = is_64bit_tdesc ();
> + lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
> + gdb_assert (lwp != nullptr);
> + int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
>
> if (use_64bit)
> {
> @@ -335,7 +337,9 @@ int
> x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
> {
> #ifdef __x86_64__
> - int use_64bit = is_64bit_tdesc ();
> + lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
> + gdb_assert (lwp != nullptr);
> + int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
>
> if (use_64bit)
> {
> @@ -351,7 +355,6 @@ x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
> #endif
>
> {
> - struct lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
> struct thread_info *thr = get_lwp_thread (lwp);
> struct regcache *regcache = get_thread_regcache (thr, 1);
> unsigned int desc[4];
> @@ -379,7 +382,7 @@ bool
> x86_target::low_cannot_store_register (int regno)
> {
> #ifdef __x86_64__
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return false;
> #endif
>
> @@ -390,7 +393,7 @@ bool
> x86_target::low_cannot_fetch_register (int regno)
> {
> #ifdef __x86_64__
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return false;
> #endif
>
> @@ -815,7 +818,7 @@ x86_target::low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
> int is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
>
> /* Is the inferior 32-bit? If so, then fixup the siginfo object. */
> - if (!is_64bit_tdesc ())
> + if (!is_64bit_tdesc (current_thread))
> return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
> FIXUP_32);
> /* No fixup for native x32 GDB. */
> @@ -1078,7 +1081,7 @@ const regs_info *
> x86_target::get_regs_info ()
> {
> #ifdef __x86_64__
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return &amd64_linux_regs_info;
> else
> #endif
> @@ -1553,7 +1556,7 @@ x86_target::install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
> char *err)
> {
> #ifdef __x86_64__
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return amd64_install_fast_tracepoint_jump_pad (tpoint, tpaddr,
> collector, lockaddr,
> orig_size, jump_entry,
> @@ -1587,7 +1590,7 @@ x86_target::get_min_fast_tracepoint_insn_len ()
> #ifdef __x86_64__
> /* On x86-64, 5-byte jump instructions with a 4-byte offset are always
> used for fast tracepoints. */
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return 5;
> #endif
>
> @@ -2931,7 +2934,7 @@ emit_ops *
> x86_target::emit_ops ()
> {
> #ifdef __x86_64__
> - if (is_64bit_tdesc ())
> + if (is_64bit_tdesc (current_thread))
> return &amd64_emit_ops;
> else
> #endif
> --
> 2.37.3
On 11/18/22 06:32, Andrew Burgess via Gdb-patches wrote:
> Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
>
>> ps_get_thread_area receives as a parameter the lwpid it must work on.
>> It then calls is_64bit_tdesc, which uses the current_thread as the
>> thread to work on. However, it is not said that both are the same.
>>
>> This became a problem when working in a following patch that pmakes
>
> s/pmakes/makes/
Fixed.
>> find_one_thread switch to a process but to no thread (current_thread ==
>> nullptr). When libthread_db needed to get the thread area,
>> is_64bit_tdesc would try to get the regcache of a nullptr thread.
>>
>> Fix that by making is_64bit_tdesc accept the thread to work on as a
>> parameter. Find the right thread from the context, when possible (when
>> we know the lwpid to work on). Otherwise, pass "current_thread", to
>> retain the existing behavior.
>>
>> Change-Id: I44394d6be92392fa28de71982fd04517ce8a3007
>> ---
>> gdbserver/linux-x86-low.cc | 27 +++++++++++++++------------
>> 1 file changed, 15 insertions(+), 12 deletions(-)
>>
>> diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
>> index d2b55f6f0d2..c98a7a461fe 100644
>> --- a/gdbserver/linux-x86-low.cc
>> +++ b/gdbserver/linux-x86-low.cc
>> @@ -275,9 +275,9 @@ static /*const*/ int i386_regmap[] =
>> per the tdesc. */
>>
>> static int
>> -is_64bit_tdesc (void)
>> +is_64bit_tdesc (thread_info *thread)
>
> I think the comment for this function needs updating, the reference to
> "current inferior" probably needs to be replaced with THREAD.
Indeed, fixed.
>
> With those changes, LGTM.
>
> Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Thanks, pushed.
Simon
@@ -275,9 +275,9 @@ static /*const*/ int i386_regmap[] =
per the tdesc. */
static int
-is_64bit_tdesc (void)
+is_64bit_tdesc (thread_info *thread)
{
- struct regcache *regcache = get_thread_regcache (current_thread, 0);
+ struct regcache *regcache = get_thread_regcache (thread, 0);
return register_size (regcache->tdesc, 0) == 8;
}
@@ -292,7 +292,9 @@ ps_get_thread_area (struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
#ifdef __x86_64__
- int use_64bit = is_64bit_tdesc ();
+ lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
+ gdb_assert (lwp != nullptr);
+ int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
if (use_64bit)
{
@@ -335,7 +337,9 @@ int
x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
{
#ifdef __x86_64__
- int use_64bit = is_64bit_tdesc ();
+ lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
+ gdb_assert (lwp != nullptr);
+ int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
if (use_64bit)
{
@@ -351,7 +355,6 @@ x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
#endif
{
- struct lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
struct thread_info *thr = get_lwp_thread (lwp);
struct regcache *regcache = get_thread_regcache (thr, 1);
unsigned int desc[4];
@@ -379,7 +382,7 @@ bool
x86_target::low_cannot_store_register (int regno)
{
#ifdef __x86_64__
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return false;
#endif
@@ -390,7 +393,7 @@ bool
x86_target::low_cannot_fetch_register (int regno)
{
#ifdef __x86_64__
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return false;
#endif
@@ -815,7 +818,7 @@ x86_target::low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
int is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
/* Is the inferior 32-bit? If so, then fixup the siginfo object. */
- if (!is_64bit_tdesc ())
+ if (!is_64bit_tdesc (current_thread))
return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
FIXUP_32);
/* No fixup for native x32 GDB. */
@@ -1078,7 +1081,7 @@ const regs_info *
x86_target::get_regs_info ()
{
#ifdef __x86_64__
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return &amd64_linux_regs_info;
else
#endif
@@ -1553,7 +1556,7 @@ x86_target::install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
char *err)
{
#ifdef __x86_64__
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return amd64_install_fast_tracepoint_jump_pad (tpoint, tpaddr,
collector, lockaddr,
orig_size, jump_entry,
@@ -1587,7 +1590,7 @@ x86_target::get_min_fast_tracepoint_insn_len ()
#ifdef __x86_64__
/* On x86-64, 5-byte jump instructions with a 4-byte offset are always
used for fast tracepoints. */
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return 5;
#endif
@@ -2931,7 +2934,7 @@ emit_ops *
x86_target::emit_ops ()
{
#ifdef __x86_64__
- if (is_64bit_tdesc ())
+ if (is_64bit_tdesc (current_thread))
return &amd64_emit_ops;
else
#endif