diff mbox series

[gdb/testsuite] Fix another timeout in gdb.base/bg-execution-repeat.exp

Message ID 20250414115102.1991-1-tdevries@suse.de
State Committed
Headers
Series [gdb/testsuite] Fix another timeout in gdb.base/bg-execution-repeat.exp |

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Commit Message

Tom de Vries April 14, 2025, 11:51 a.m. UTC 
  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.
---
 gdb/testsuite/gdb.base/bg-execution-repeat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


base-commit: e25c84752c9df2bf3a999b53afb58e5bebaf3b7c

Comments

Alexandra Petlanova Hajkova April 16, 2025, 3:26 p.m. UTC | #1 
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>
Tom de Vries April 16, 2025, 3:40 p.m. UTC | #2 
On 4/16/25 17:26, Alexandra Petlanova Hajkova wrote:
> 
> 
> On Mon, Apr 14, 2025 at 1:51 PM Tom de Vries <tdevries@suse.de 
> <mailto: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.
> 

Hi Alexandra,

thanks for the review, pushed.

- Tom

> Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com 
> <mailto:ahajkova@redhat.com>>
diff mbox series

Patch

diff --git a/gdb/testsuite/gdb.base/bg-execution-repeat.c b/gdb/testsuite/gdb.base/bg-execution-repeat.c
index 8e9bae4dfbb..3c0cc763e48 100644
--- a/gdb/testsuite/gdb.base/bg-execution-repeat.c
+++ b/gdb/testsuite/gdb.base/bg-execution-repeat.c
@@ -37,9 +37,9 @@  main (void)
 {
   alarm (60);
 
+  do_wait = 1;
   foo ();
 
-  do_wait = 1;
   wait ();
   /* do_wait set to 0 externally.  */