On Mon, Apr 14, 2025 at 1:51 PM Tom de Vries <tdevries@suse.de> wrote:

> With test-case gdb.base/bg-execution-repeat.exp, occasionally I run into a
> timeout:
> ...
> (gdb) c 1&
> Will stop next time breakpoint 1 is reached.  Continuing.
> (gdb) PASS: $exp: c 1&: c 1&
>
> Breakpoint 2, foo () at bg-execution-repeat.c:23
> 23        return 0; /* set break here */
> PASS: $exp: c 1&: breakpoint hit 1
>
> Will stop next time breakpoint 2 is reached.  Continuing.
> (gdb) PASS: $exp: c 1&: repeat bg command
> print 1
> $1 = 1
> (gdb) PASS: $exp: c 1&: input still accepted
> interrupt
> (gdb) PASS: $exp: c 1&: interrupt
>
> Program received signal SIGINT, Interrupt.
> foo () at bg-execution-repeat.c:24
> 24      }
> PASS: $exp: c 1&: interrupt received
> set var do_wait=0
> (gdb) PASS: $exp: c 1&: set var do_wait=0
> continue&
> Continuing.
> (gdb) PASS: $exp: c 1&: continue&
> FAIL: $exp: c 1&: breakpoint hit 2 (timeout)
> ...
>
> I can reproduce it reliably by adding a "sleep (1)" before the "do_wait =
> 1"
> in the .c file.
>
> The timeout happens as follows:
> - with the inferior stopped at main, gdb continues (command c 1&)
> - the inferior hits the breakpoint at foo
> - gdb continues (using the repeat command functionality)
> - the inferior is interrupted
> - inferior variable do_wait gets set to 0.  The assumption here is that the
>   inferior has progressed enough that do_wait is set to 1 at that point,
> but
>   that happens not to be the case.  Consequently, this has no effect.
> - gdb continues
> - the inferior sets do_wait to 1
> - the inferior enters the wait function, and wait for do_wait to become 0,
>   which never happens.
>
> Fix this by moving the "do_wait = 1" to before the first call to foo.
>
> Tested on x86_64-linux.
> ---
>

Hi Tom,

I also tested this on aarch64 and it works as expected, I think it's a
reasonable change.

Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>