From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id CE31C3858023 for ; Tue, 2 Nov 2021 11:38:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CE31C3858023 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 1234F2193C for ; Tue, 2 Nov 2021 11:38:27 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F348F13C8A for ; Tue, 2 Nov 2021 11:38:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 9VAuOjIjgWGsTQAAMHmgww (envelope-from ) for ; Tue, 02 Nov 2021 11:38:26 +0000 Subject: Re: [PATCH][gdb/testsuite] Work around skip_prologue problems in gdb.threads/process-dies-while-detaching.exp To: gdb-patches@sourceware.org References: <20211029192419.GA26416@delia> From: Tom de Vries Message-ID: <2cc5e63d-5be1-a5c7-b1cd-6058223a5a19@suse.de> Date: Tue, 2 Nov 2021 12:38:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20211029192419.GA26416@delia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-13.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Nov 2021 11:38:29 -0000 On 10/29/21 9:24 PM, Tom de Vries via Gdb-patches wrote: > Hi, > > On powerpc64le-linux, I run into: > ... > [Inferior 1 (process 5156) exited normally]^M > (gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: \ > detach: detach: continue to breakpoint: _exit (the program exited) > ... > > What happens is the following: > - a breakpoint is set on _exit, > - a continue is issued > - the continue is supposed to hit the breakpoint, but instead > the program exits. > > I traced this down to the breakpoint on _exit being set too far from function > entry. This is caused by the skip_prologue function (in rs6000-tdep.c) > optimistically ignoring insns it doesn't recognize. In particular, it walks > past the system call instruction "sc" which initiates the actual exit. > > While this needs fixing, Filed here: https://sourceware.org/bugzilla/show_bug.cgi?id=28527 . Submitted patch here: https://sourceware.org/pipermail/gdb-patches/2021-November/183016.html . Thanks, - Tom > we don't want to be testing this behaviour in this > test-case. > > [ Initially I tried to fix it by setting a breakpoint on "*_exit" instead, but > that one only sets one location. The breakpoint on "_exit" sets two > locations, one in /lib64/libc.so.6 and one in /lib64/ld64.so.2. I tried on > x86_64 and there the breakpoint on "*_exit" mapped to the /lib64/libc.so.6 > location, and the test-case passed. But on powerpc it mapped to the > /lib64/ld64.so.2 location and I still got the same failures. ] > > Fix this by setting two breakpoints on the calls to _exit and exit instead. > > Tested on x86_64-linux and powerpc64le-linux. > > Any comments? > > Thanks, > - Tom > > [gdb/testsuite] Work around skip_prologue problems in gdb.threads/process-dies-while-detaching.exp > > --- > gdb/testsuite/gdb.threads/process-dies-while-detaching.c | 4 ++-- > gdb/testsuite/gdb.threads/process-dies-while-detaching.exp | 8 ++++++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/gdb/testsuite/gdb.threads/process-dies-while-detaching.c b/gdb/testsuite/gdb.threads/process-dies-while-detaching.c > index 502b4622614..c4c0b0a648b 100644 > --- a/gdb/testsuite/gdb.threads/process-dies-while-detaching.c > +++ b/gdb/testsuite/gdb.threads/process-dies-while-detaching.c > @@ -46,7 +46,7 @@ void * > thread_function (void *arg) > { > pthread_barrier_wait (&start_threads_barrier); > - _exit (0); > + _exit (0); /* Exit in thread. */ > } > > /* The fork child's entry point. */ > @@ -63,7 +63,7 @@ child_function (void) > pthread_create (&threads[i], NULL, thread_function, NULL); > pthread_barrier_wait (&start_threads_barrier); > > - exit (0); > + exit (0); /* Exit in child. */ > } > > /* This is defined by the .exp file if testing the multi-process > diff --git a/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp b/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp > index cabbc4faacc..bbf1e0e6740 100644 > --- a/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp > +++ b/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp > @@ -126,8 +126,12 @@ proc detach_and_expect_exit {inf_output_re test} { > # Run to _exit in the child. > > proc continue_to_exit_bp {} { > - gdb_breakpoint "_exit" temporary > - gdb_continue_to_breakpoint "_exit" ".*_exit.*" > + set line [gdb_get_line_number "Exit in child"] > + gdb_breakpoint $line temporary > + set line [gdb_get_line_number "Exit in thread"] > + gdb_breakpoint $line temporary > + gdb_continue_to_breakpoint "exit" ".*exit.*" > + delete_breakpoints > } > > # If testing single-process, simply detach from the process. >