Avoid race condition when handling a SIGWINCH signal
Commit Message
The control variable win_resized must be cleared before responding to
it.
Otherwise there is a small window where another SIGWINCH might occur in
between the handling of an earlier SIGWINCH and the clearing of
win_resized, at which point win_resized would be set (again) by the
signal handler. Shortly thereafter we would clear win_resized even
though we only handled the earlier SIGWINCH but not the latest one.
This chain of events is all avoided if we clear win_resized first.
gdb/ChangeLog:
* tui/tui-win.c (tui_async_resize_screen): Clear win_resized
first before resizing the window.
* tui.c (tui_enable): Likewise.
---
gdb/tui/tui-win.c | 2 +-
gdb/tui/tui.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
Comments
On 05/13/2015 02:33 PM, Patrick Palka wrote:
> The control variable win_resized must be cleared before responding to
> it.
>
> Otherwise there is a small window where another SIGWINCH might occur in
> between the handling of an earlier SIGWINCH and the clearing of
> win_resized, at which point win_resized would be set (again) by the
> signal handler. Shortly thereafter we would clear win_resized even
> though we only handled the earlier SIGWINCH but not the latest one.
> This chain of events is all avoided if we clear win_resized first.
>
> gdb/ChangeLog:
>
> * tui/tui-win.c (tui_async_resize_screen): Clear win_resized
> first before resizing the window.
> * tui.c (tui_enable): Likewise.
OK.
Thanks,
Pedro Alves
@@ -858,10 +858,10 @@ tui_async_resize_screen (gdb_client_data arg)
}
else
{
+ tui_set_win_resized_to (FALSE);
tui_resize_all ();
tui_refresh_all_win ();
tui_update_gdb_sizes ();
- tui_set_win_resized_to (FALSE);
tui_redisplay_readline ();
}
}
@@ -492,8 +492,8 @@ tui_enable (void)
window. */
if (tui_win_resized ())
{
- tui_resize_all ();
tui_set_win_resized_to (FALSE);
+ tui_resize_all ();
}
if (deprecated_safe_get_selected_frame ())