From patchwork Wed Jan 8 15:25:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shahab Vahedi X-Patchwork-Id: 37257 Received: (qmail 28638 invoked by alias); 8 Jan 2020 15:26:00 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 28619 invoked by uid 89); 8 Jan 2020 15:26:00 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, FREEMAIL_FROM, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.1 spammy=HX-Received:a19 X-HELO: mail-lf1-f67.google.com Received: from mail-lf1-f67.google.com (HELO mail-lf1-f67.google.com) (209.85.167.67) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 08 Jan 2020 15:25:58 +0000 Received: by mail-lf1-f67.google.com with SMTP id f15so2720444lfl.13 for ; Wed, 08 Jan 2020 07:25:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=dD5V4Xc0HHQGCqGWJV3o2iZyjr57puSqsilulL6bp4U=; b=VEPm/6aR4ie+vz6h5svBPUNVUwhZyxJDzBLpsdw4zts+s+CSuAHs6qCzqISK4rS2On Ob9N9bz7Ks4ITXRy5E/T+hsK3xWAj8Hv3EqdrjAcUuaONr9tneqKsWCg9jWXbpSoyKXH NxawbbginueWhhpEDaLO+eRorvbX8eUOw0NnNa6E+OBiYK2dWKrNSEKKu/LnL82zxs2o 1qY3czjxykDYWAfK6pRfW9/QsU8BqxFc0+7U25fOlkYp2CnsHrNAEMWoOHdR97MYlWl+ JVDB36XM10g+Vz0ufSUJDvNHVaHCLHKShc82l05VIPZ/hjwPEjyRcM7UMKaG4H+GxK90 bOYw== Return-Path: Received: from archie.localdomain ([2a03:1b20:6:f011::2d]) by smtp.gmail.com with ESMTPSA id h24sm1427610ljl.80.2020.01.08.07.25.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Jan 2020 07:25:55 -0800 (PST) From: Shahab Vahedi To: gdb-patches@sourceware.org Cc: Shahab Vahedi , Pedro Alves , Andrew Burgess , Claudiu Zissulescu , Francois Bedard Subject: [PATCH] GDB: Treat memory exception from tui_disassemble() gracefully Date: Wed, 8 Jan 2020 16:25:50 +0100 Message-Id: <20200108152550.112120-1-shahab.vahedi@gmail.com> MIME-Version: 1.0 From: Shahab Vahedi In TUI mode, when the assembly layout reaches the end of a binary, GDB wants to disassemle the addresses beyond the last valid ones. This results in a "MEMORY_ERROR" exception to be thrown when tui_disasm_window::set_contents() invokes tui_disassemble(). When that happens set_contents() bails out prematurely without filling the "content" for the valid addresses. This eventually leads to no assembly lines or termination of GDB when you scroll down to the last lines of the program. With this change, tui_disassemble() is surrounded with try/catch. If a MEMORY_ERROR exception is caught, it is ignored. The issue has been discussed at length in bug 25345: https://sourceware.org/bugzilla/show_bug.cgi?id=25345 gdb/ChangeLog: 2020-01-08 Shahab Vahedi * tui/tui-disasm.c (tui_disasm_window::set_contents): Handle MEMORY_ERROR exception gracefully. --- gdb/tui/tui-disasm.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c index 98c691f3387..7faaa45f039 100644 --- a/gdb/tui/tui-disasm.c +++ b/gdb/tui/tui-disasm.c @@ -226,7 +226,18 @@ tui_disasm_window::set_contents (struct gdbarch *arch, /* Get temporary table that will hold all strings (addr & insn). */ std::vector asm_lines (max_lines); size_t addr_size = 0; - tui_disassemble (gdbarch, asm_lines, pc, 0, max_lines, &addr_size); + try + { + tui_disassemble (gdbarch, asm_lines, pc, 0, max_lines, &addr_size); + } + catch (const gdb_exception &except) + { + /* In cases where max_lines is asking tui_disassemble() to fetch + too much, like when PC goes past the valid address range, a + MEMORY_ERROR is thrown, but it is alright. */ + if (except.error != MEMORY_ERROR) + throw; + } /* Align instructions to the same column. */ insn_pos = (1 + (addr_size / tab_len)) * tab_len;