From 3be966f69d6967d2857baa3efb0bc043081e0a00 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Thu, 9 Jan 2020 22:38:22 +0000 Subject: [PATCH] gdb/testsuite: Fix race condition in gdb.base/skip.exp In this commit: commit 5024637fac653914d471808288dc3221bc7ec089 Date: Sun Dec 15 11:05:47 2019 +0100 Fix skip.exp test failure observed with gcc-9.2.0 A race condition was introduced into the gdb.base/skip.exp test when this line: gdb_test "step" "foo \\(\\) at.*" "step 3" Was changed to this: gdb_test "step" "foo \\(\\) at.*" "step 3" "main \\(\\) at .*" "step" Before the above change we expected GDB to behave like this: (gdb) step foo () at /path/to/gdb/testsuite/gdb.base/skip.c:42 42 return 0; (gdb) However, when the test is compiled with GCC 9.2.0 we get a different behaviour, and so we need a second 'step', like this: (gdb) step main () at /path/to/gdb.base/skip.c:32 32 x = baz ((bar (), foo ())); (gdb) step foo () at /path/to/gdb/testsuite/gdb.base/skip.c:42 42 return 0; (gdb) Now the change to the test matches against 'main () at .*', however if GDB or expect is being slow then we might only get to see output like this: (gdb) step main () at /path/to/g This will happily match the question pattern, so we send 'step' to GDB again. Now GDB continues to produce output which expect accepts, we now see this: b.base/skip.c:32 32 x = baz ((bar (), foo ())); (gdb) This has carried on from where the previous block of output left off. This doesn't match the final pattern 'foo \\(\\) at.*', but it does match the prompt pattern that gdb_test_multiple adds, and so we report the test as failing. The solution is to simply ensure that the question consumes everything up to, and including the prompt. This ensures that the prompt can't then match the failure case. The new test line becomes: gdb_test "step" "foo \\(\\) at.*" "step 3" \ "main \\(\\) at .*\r\n$gdb_prompt " "step" gdb/testsuite/ChangeLog: * gdb.base/skip.exp: Fix race condition in test. Change-Id: I9f0b0b52ef1b4f980bfaa8fe405ff06d520f3482 --- gdb/testsuite/ChangeLog | 4 ++++ gdb/testsuite/gdb.base/skip.exp | 9 ++++++--- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 3f243641b8b..cecd384d5da 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2020-01-09 Andrew Burgess + + * gdb.base/skip.exp: Fix race condition in test. + 2020-01-06 Andrew Burgess * gdb.base/backtrace.c: New file. diff --git a/gdb/testsuite/gdb.base/skip.exp b/gdb/testsuite/gdb.base/skip.exp index d7dd3cedbec..513c9fcc82e 100644 --- a/gdb/testsuite/gdb.base/skip.exp +++ b/gdb/testsuite/gdb.base/skip.exp @@ -144,7 +144,8 @@ with_test_prefix "step after disabling 3" { gdb_test "step" ".*" "step 2"; # Return from bar() # With gcc 9.2.0 we jump once back to main before entering foo here. # If that happens try to step a second time. - gdb_test "step" "foo \\(\\) at.*" "step 3" "main \\(\\) at .*" "step" + gdb_test "step" "foo \\(\\) at.*" "step 3" \ + "main \\(\\) at .*\r\n$gdb_prompt " "step" gdb_test "step" ".*" "step 4"; # Return from foo() gdb_test "step" "main \\(\\) at.*" "step 5" } @@ -265,7 +266,8 @@ with_test_prefix "step using -fu for baz" { gdb_test "step" ".*" "step 2"; # Return from bar() # With gcc 9.2.0 we jump once back to main before entering foo here. # If that happens try to step a second time. - gdb_test "step" "foo \\(\\) at.*" "step 3" "main \\(\\) at.*" "step" + gdb_test "step" "foo \\(\\) at.*" "step 3" \ + "main \\(\\) at .*\r\n$gdb_prompt " "step" gdb_test "step" ".*" "step 4"; # Return from foo() gdb_test "step" "main \\(\\) at.*" "step 5" } @@ -282,7 +284,8 @@ with_test_prefix "step using -rfu for baz" { gdb_test "step" ".*" "step 2"; # Return from bar() # With gcc 9.2.0 we jump once back to main before entering foo here. # If that happens try to step a second time. - gdb_test "step" "foo \\(\\) at.*" "step 3" "main \\(\\) at.*" "step" + gdb_test "step" "foo \\(\\) at.*" "step 3" \ + "main \\(\\) at .*\r\n$gdb_prompt " "step" gdb_test "step" ".*" "step 4"; # Return from foo() gdb_test "step" "main \\(\\) at.*" "step 5" } -- 2.30.2