[PATCH] [gdb] Fix FAIL in gdb.threads/killed-outside.exp

[Tom de Vries]

[ correcting gdb/testsuite -> gdb ]

On 10/29/21 12:04 PM, Tom de Vries via Gdb-patches wrote:
> On openSUSE Leap 15.2 I run into:
> ...
> (gdb) PASS: gdb.threads/killed-outside.exp: get pid of inferior
> Executing on target: kill -9 24753    (timeout = 300)
> builtin_spawn -ignore SIGHUP kill -9 24753^M
> continue^M
> Continuing.^M
> Couldn't get registers: No such process.^M
> (gdb) [Thread 0x7ffff74c4700 (LWP 24757) exited]^M
> ^M
> Program terminated with signal SIGKILL, Killed.^M
> The program no longer exists.^M
> FAIL: gdb.threads/killed-outside.exp: prompt after first continue (timeout)
> ...
> 
> The test-case expects the messages:
> - "Program terminated with signal SIGKILL, Killed."
> - "The program no longer exists."
> before the prompt.
> 
> When debugging the "Couldn't get registers: No such process" message using
> this command-line reproduction:
> ...
> $ gdb -q outputs/gdb.threads/killed-outside/killed-outside \
>     -ex "tb all_started" \
>     -ex "run" \
>     -ex 'shell kill -9 $(pidof killed-outside)' \
>     -ex continue
> ...
> I noticed that the first time this error is thrown, it's caught by
> regcache_read_pc_protected.
> 
> The second time the error is thrown, it's from a regular regcache_read_pc in
> resume_1, and we see the error show up.
> 
> Fix this by using regcache_read_pc_protected in resume_1 as well.
> 
> Tested on x86_64-linux.
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=26664
> ---
>  gdb/infrun.c                                 |  2 +-
>  gdb/testsuite/gdb.threads/killed-outside.exp | 15 +++------------
>  2 files changed, 4 insertions(+), 13 deletions(-)
> 
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 4698fe20cc1..26d11c57574 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -2268,7 +2268,7 @@ resume_1 (enum gdb_signal sig)
>        step = false;
>      }
>  
> -  CORE_ADDR pc = regcache_read_pc (regcache);
> +  CORE_ADDR pc = regcache_read_pc_protected (regcache);
>  
>    infrun_debug_printf ("step=%d, signal=%s, trap_expected=%d, "
>  		       "current thread [%s] at %s",
> diff --git a/gdb/testsuite/gdb.threads/killed-outside.exp b/gdb/testsuite/gdb.threads/killed-outside.exp
> index 7050a4b84ba..f37d896d80d 100644
> --- a/gdb/testsuite/gdb.threads/killed-outside.exp
> +++ b/gdb/testsuite/gdb.threads/killed-outside.exp
> @@ -40,19 +40,10 @@ sleep 2
>  set no_such_process_msg "Couldn't get registers: No such process\."
>  set killed_msg "Program terminated with signal SIGKILL, Killed\."
>  set no_longer_exists_msg "The program no longer exists\."
> -set not_being_run_msg "The program is not being run\."
>  
> -gdb_test_multiple "continue" "prompt after first continue" {
> -    -re "Continuing\.\r\n$no_such_process_msg\r\n$no_such_process_msg\r\n$gdb_prompt " {
> -	pass $gdb_test_name
> -	# Two times $no_such_process_msg.  The bug condition was triggered, go
> -	# check for it.
> -	gdb_test_multiple "" "messages" {
> -	    -re ".*$killed_msg.*$no_longer_exists_msg\r\n" {
> -		pass $gdb_test_name
> -		gdb_test "continue" $not_being_run_msg "second continue"
> -	    }
> -	}
> +gdb_test_multiple "continue" "" {
> +    -re "$no_such_process_msg.*$gdb_prompt " {
> +	fail $gdb_test_name
>      }
>      -re -wrap ".*$killed_msg.*$no_longer_exists_msg" {
>  	pass $gdb_test_name
> 
> base-commit: 208eb58158c2f23a7fbaff32a4912dbbb8d0ee5c
>