From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx07-00178001.pphosted.com (mx07-00178001.pphosted.com [185.132.182.106]) by sourceware.org (Postfix) with ESMTPS id 8C5B73858404 for ; Thu, 13 Oct 2022 10:53:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8C5B73858404 Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 29D8kT1f021764; Thu, 13 Oct 2022 12:53:39 +0200 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3k64m7mvwm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 13 Oct 2022 12:53:39 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id BDFBA100034; Thu, 13 Oct 2022 12:53:34 +0200 (CEST) Received: from Webmail-eu.st.com (shfdag1node3.st.com [10.75.129.71]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id B3E962248CB; Thu, 13 Oct 2022 12:53:33 +0200 (CEST) Received: from jkgcxl0002.jkg.st.com (10.75.127.48) by SHFDAG1NODE3.st.com (10.75.129.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2375.31; Thu, 13 Oct 2022 12:53:32 +0200 From: =?UTF-8?q?Torbj=C3=B6rn=20SVENSSON?= To: Subject: [PATCH v3] gdb/arm: Stop unwinding on error, but do not assert Date: Thu, 13 Oct 2022 12:53:06 +0200 Message-ID: <20221013105305.657219-1-torbjorn.svensson@foss.st.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.75.127.48] X-ClientProxiedBy: SFHDAG2NODE3.st.com (10.75.127.6) To SHFDAG1NODE3.st.com (10.75.129.71) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-13_06,2022-10-13_01,2022-06-22_01 X-Spam-Status: No, score=-11.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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: Thu, 13 Oct 2022 10:53:45 -0000 When it's impossible to read the FPCCR and XPSR, the unwinding is unpredictable as the it's not possible to determine the correct frame size or padding. The only sane thing to do in this condition is to stop the unwinding. Example session wihtout this patch: (gdb) bt #0 SVC_Handler () at .../GPIO/GPIO_EXTI/Src/stm32f4xx_it.c:112 .../gdb/arm-tdep.c:3594: internal-error: arm_m_exception_cache: Assertion `safe_read_memory_unsigned_integer (FPCCR, ARM_INT_REGISTER_SIZE, byte_order, &fpccr)' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. ----- Backtrace ----- 0x5583bfb2a157 gdb_internal_backtrace_1 ... --------------------- This is a bug, please report it. For instructions, see: . Aborted (core dumped) Example session with this patch: (gdb) bt #0 SVC_Handler () at .../GPIO/GPIO_EXTI/Src/stm32f4xx_it.c:112 warning: Could not fetch required FPCCR content. Further unwind is impossible. #1 (gdb) Signed-off-by: Torbjörn SVENSSON --- gdb/arm-tdep.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 041e6afefed..bdbff247188 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -3591,9 +3591,13 @@ arm_m_exception_cache (frame_info_ptr this_frame) ULONGEST fpcar; /* Read FPCCR register. */ - gdb_assert (safe_read_memory_unsigned_integer (FPCCR, - ARM_INT_REGISTER_SIZE, - byte_order, &fpccr)); + if (!safe_read_memory_unsigned_integer (FPCCR, ARM_INT_REGISTER_SIZE, + byte_order, &fpccr)) + { + warning (_("Could not fetch required FPCCR content. Further " + "unwind is impossible.")); + return nullptr; + } /* Read FPCAR register. */ if (!safe_read_memory_unsigned_integer (FPCAR, ARM_INT_REGISTER_SIZE, @@ -3669,9 +3673,15 @@ arm_m_exception_cache (frame_info_ptr this_frame) aligner between the top of the 32-byte stack frame and the previous context's stack pointer. */ ULONGEST xpsr; - gdb_assert (safe_read_memory_unsigned_integer (cache->saved_regs[ - ARM_PS_REGNUM].addr (), 4, - byte_order, &xpsr)); + if (!safe_read_memory_unsigned_integer (cache->saved_regs[ARM_PS_REGNUM] + .addr (), ARM_INT_REGISTER_SIZE, + byte_order, &xpsr)) + { + warning (_("Could not fetch required XPSR content. Further unwind " + "is impossible.")); + return nullptr; + } + if (bit (xpsr, 9) != 0) { CORE_ADDR new_sp = arm_cache_get_prev_sp_value (cache, tdep) + 4; @@ -3703,6 +3713,14 @@ arm_m_exception_this_id (frame_info_ptr this_frame, *this_cache = arm_m_exception_cache (this_frame); cache = (struct arm_prologue_cache *) *this_cache; + /* Unwind of this frame is not possible. Return outer_frame_id to stop the + unwinding. */ + if (cache == nullptr) + { + *this_id = outer_frame_id; + return; + } + /* Our frame ID for a stub frame is the current SP and LR. */ arm_gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame)); @@ -3725,6 +3743,11 @@ arm_m_exception_prev_register (frame_info_ptr this_frame, *this_cache = arm_m_exception_cache (this_frame); cache = (struct arm_prologue_cache *) *this_cache; + /* It's not allowed to call prev_register when this_id has returned the + outer_frame_id. The arm_m_exception_cache function will return NULL when + the frame cannot be properly unwinded. */ + gdb_assert (cache != nullptr); + /* The value was already reconstructed into PREV_SP. */ arm_gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame)); -- 2.25.1