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[83.42.57.116]) by smtp.gmail.com with ESMTPSA id p11sm3868406ejg.64.2020.04.09.10.51.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Apr 2020 10:51:50 -0700 (PDT) Subject: Re: [PATCH 1/2] gdbstub: Assert len read from each register To: Peter Xu , qemu-devel@nongnu.org References: <20200409164954.36902-1-peterx@redhat.com> <20200409164954.36902-2-peterx@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: <0121e4b2-c6dd-d0c4-a7d5-490e08bee923@redhat.com> Date: Thu, 9 Apr 2020 19:51:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200409164954.36902-2-peterx@redhat.com> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?Q?Alex_Benn=c3=a9e?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/9/20 6:49 PM, Peter Xu wrote: > This can expose the issue earlier on which register returned the wrong > result. > > Signed-off-by: Peter Xu > --- > gdbstub.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/gdbstub.c b/gdbstub.c > index 171e150950..f763545e81 100644 > --- a/gdbstub.c > +++ b/gdbstub.c > @@ -911,17 +911,22 @@ static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg) > CPUClass *cc = CPU_GET_CLASS(cpu); > CPUArchState *env = cpu->env_ptr; > GDBRegisterState *r; > + int len = 0, orig_len = buf->len; > > if (reg < cc->gdb_num_core_regs) { > - return cc->gdb_read_register(cpu, buf, reg); > + len = cc->gdb_read_register(cpu, buf, reg); This change the code flow. We could add ...: goto out; > } ... or use else? > > for (r = cpu->gdb_regs; r; r = r->next) { > if (r->base_reg <= reg && reg < r->base_reg + r->num_regs) { > - return r->get_reg(env, buf, reg - r->base_reg); > + len = r->get_reg(env, buf, reg - r->base_reg); > + break; > } > } > - return 0; > + out: > + assert(len == buf->len - orig_len); > + > + return len; > } > > static int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg) >