On 28/03/2018 19:32, Vladimir Sementsov-Ogievskiy wrote:
> When debugging a coredump, pthread_self can't be obtained from
> function arch_prctl. Moreover if qemu crashed in coroutine, we
> can't find 'start_thread' in current stack-trace. So, add a method,
> actually proposed in 1138f24645e9e, which should work for gdb
> version >= 7.3.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
New-enough gdb can also use gdb.selected_thread()
> ---
> scripts/qemugdb/coroutine.py | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py
> index ab699794ab..ffaa45c464 100644
> --- a/scripts/qemugdb/coroutine.py
> +++ b/scripts/qemugdb/coroutine.py
> @@ -14,6 +14,7 @@
> # GNU GPL, version 2 or (at your option) any later version.
>
> import gdb
> +import re
>
> VOID_PTR = gdb.lookup_type('void').pointer()
>
> @@ -28,7 +29,17 @@ def get_fs_base():
> return fs_base
>
> def pthread_self():
> - '''Fetch pthread_self() from the glibc start_thread function.'''
> + # Try read pthread_self from gdb command 'info threads'.
> + # Will fail for old gdb.
> + try:
> + threads = gdb.execute('info threads', False, True)
> + m = re.search('^\* 1 Thread (0x[0-9a-f]+)', threads, re.MULTILINE)
I don't think hard-coding "1" works here, and the spacing of the table
might differ as well. However, looking for the asterisk seems safe from
a quick look at gdb source, and "Thread" looks like it isn't localized.
Paolo
> + return int(m.group(1), 16)
> + except TypeError:
> + # gdb doesn't support third parameter for execute
> + pass
> +
> + # Try fetch pthread_self() from the glibc start_thread function.
> f = gdb.newest_frame()
> while f.name() != 'start_thread':
> f = f.older()
>
