From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30222 invoked by alias); 17 Nov 2014 07:09:31 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 30211 invoked by uid 89); 17 Nov 2014 07:09:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-oi0-f50.google.com Received: from mail-oi0-f50.google.com (HELO mail-oi0-f50.google.com) (209.85.218.50) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Mon, 17 Nov 2014 07:09:29 +0000 Received: by mail-oi0-f50.google.com with SMTP id a141so6578666oig.9 for ; Sun, 16 Nov 2014 23:09:27 -0800 (PST) X-Received: by 10.202.49.131 with SMTP id x125mr15739450oix.17.1416208167070; Sun, 16 Nov 2014 23:09:27 -0800 (PST) MIME-Version: 1.0 Received: by 10.60.170.142 with HTTP; Sun, 16 Nov 2014 23:08:46 -0800 (PST) In-Reply-To: References: <1409238683-17886-1-git-send-email-teawater@gmail.com> From: Hui Zhu Date: Mon, 17 Nov 2014 07:09:00 -0000 Message-ID: Subject: Re: [PATCH] Add gdbarch_sizeof_g_packet to "struct remote_arch_state" to handle the issue that get error "Remote 'g' packet reply is too long" with qemu-system-x86_64 To: gdb-patches ml Cc: Hui Zhu Content-Type: text/plain; charset=ISO-8859-1 X-IsSubscribed: yes X-SW-Source: 2014-11/txt/msg00395.txt.bz2 Ping. Or I just enjoy it with myself. :P Thanks, Hui On Tue, Sep 2, 2014 at 11:26 AM, Hui Zhu wrote: > Ping. > > Thanks, > Hui > > On Thu, Aug 28, 2014 at 11:11 PM, Hui Zhu wrote: >> If qemu-system-x86_64 start with -S, gdb will get error "Remote 'g' packet reply >> is too long", for example: >> sudo qemu-system-x86_64 -nographic -k en-us -kernel /boot/vmlinuz-3.13.0-34-generic -gdb tcp::12345 -append "console=ttyS0,115200 root=/dev/sda rw kmemleak=off" -S -m 512 -smp 1 >> gdb /usr/lib/debug/boot/vmlinux-$(uname -r) >> (gdb) set debug remote 1 >> (gdb) target remote :12345 >> ... >> ... >> Sending packet: $g#67...Ack >> Packet received: 0000000000000000630600000000000000000000000000000000000 >> 000000000f0ff00000200000000f00000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000007f03000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 0000000000000000000000000000000000000000000000000801f0000 >> (gdb) b start_kernel >> (gdb) c >> Continuing. >> ... >> ... >> Sending packet: $g#67...Ack >> Packet received: 0000000000000000d381ffffffff000040000000000000000010060 >> 00000000000f009000000000010f4ce81ffffffff981fc081ffffffff901fc081fffffff >> f0030c1010000000000000000000000000000000000000000a869270200000000fffffff >> f0000000020000000000000002051d381ffffffffb01fc081ffffffff385bd381fffffff >> f96000000100000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 07f030000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 0801f0000 >> Remote 'g' packet reply is too long: 0000000000000000d381ffffffff0000400 >> 0000000000000001006000000000000f009000000000010f4ce81ffffffff981fc081fff >> fffff901fc081ffffffff0030c1010000000000000000000000000000000000000000a86 >> 9270200000000ffffffff0000000020000000000000002051d381ffffffffb01fc081fff >> fffff385bd381ffffffff960000001000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 0000000000000000000007f0300000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000000000000000000000000000000000000000000000000000000 >> 000000000000000000000801f0000 >> (gdb) c >> Continuing. >> Cannot execute this command while the selected thread is running. >> >> The root cause of this issue is: >> When GDB load a debug binary, function init_remote_state will be called and >> rsa->sizeof_g_packet will be initialized. >> /* Record the maximum possible size of the g packet - it may turn out >> to be smaller. */ >> rsa->sizeof_g_packet = map_regcache_remote_table (gdbarch, rsa->regs); >> When remote.c get first reply of g that its size is smaller than >> rsa->sizeof_g_packet in function process_g_packet, sizeof_g_packet will be >> updated to this smaller size. >> rsa->sizeof_g_packet = buf_len / 2; >> When inferior is breaked by breakpoint, because some reason architecture reason, >> QEMU send a packet for "g" that is more bigger than previous one. Then GDB will >> get error in function process_g_packet. >> /* Further sanity checks, with knowledge of the architecture. */ >> if (buf_len > 2 * rsa->sizeof_g_packet) >> error (_("Remote 'g' packet reply is too long: %s"), rs->buf); >> >> To handle this issue: >> This patch add "gdbarch_sizeof_g_packet" to "struct remote_arch_state", it will >> keep the size of g packet that get from gdbarch. And function process_g_packet >> use it do the check for the reply of "g". And update sizeof_g_packet if it is >> not same with reply of "g". >> >> 2014-08-21 Hui Zhu >> >> * remote.c (struct remote_arch_state): Add gdbarch_sizeof_g_packet. >> (init_remote_state): Initialize rsa->gdbarch_sizeof_g_packet. >> (process_g_packet): Check buf_len with rsa->gdbarch_sizeof_g_packet. >> Update code to update rsa->sizeof_g_packet if buf_len is not for it. >> --- >> gdb/remote.c | 18 ++++++++++++------ >> 1 file changed, 12 insertions(+), 6 deletions(-) >> >> diff --git a/gdb/remote.c b/gdb/remote.c >> index 357e9f2..9727915 100644 >> --- a/gdb/remote.c >> +++ b/gdb/remote.c >> @@ -439,6 +439,11 @@ struct remote_arch_state >> /* Description of the remote protocol registers. */ >> long sizeof_g_packet; >> >> + /* The sizeof_g_packet will be changed in some GDBstub (QEMU) when it executes. >> + Description of the remote protocol registers that get form current >> + gdbarch. */ >> + long gdbarch_sizeof_g_packet; >> + >> /* Description of the remote protocol registers indexed by REGNUM >> (making an array gdbarch_num_regs in size). */ >> struct packet_reg *regs; >> @@ -673,7 +678,8 @@ init_remote_state (struct gdbarch *gdbarch) >> >> /* Record the maximum possible size of the g packet - it may turn out >> to be smaller. */ >> - rsa->sizeof_g_packet = map_regcache_remote_table (gdbarch, rsa->regs); >> + rsa->gdbarch_sizeof_g_packet = map_regcache_remote_table (gdbarch, rsa->regs); >> + rsa->sizeof_g_packet = rsa->gdbarch_sizeof_g_packet; >> >> /* Default maximum number of characters in a packet body. Many >> remote stubs have a hardwired buffer size of 400 bytes >> @@ -693,8 +699,8 @@ init_remote_state (struct gdbarch *gdbarch) >> header / footer. NOTE: cagney/1999-10-26: I suspect that 8 >> (``$NN:G...#NN'') is a better guess, the below has been padded a >> little. */ >> - if (rsa->sizeof_g_packet > ((rsa->remote_packet_size - 32) / 2)) >> - rsa->remote_packet_size = (rsa->sizeof_g_packet * 2 + 32); >> + if (rsa->gdbarch_sizeof_g_packet > ((rsa->remote_packet_size - 32) / 2)) >> + rsa->remote_packet_size = (rsa->gdbarch_sizeof_g_packet * 2 + 32); >> >> /* Make sure that the packet buffer is plenty big enough for >> this architecture. */ >> @@ -6070,7 +6076,7 @@ process_g_packet (struct regcache *regcache) >> buf_len = strlen (rs->buf); >> >> /* Further sanity checks, with knowledge of the architecture. */ >> - if (buf_len > 2 * rsa->sizeof_g_packet) >> + if (buf_len > 2 * rsa->gdbarch_sizeof_g_packet) >> error (_("Remote 'g' packet reply is too long: %s"), rs->buf); >> >> /* Save the size of the packet sent to us by the target. It is used >> @@ -6079,11 +6085,11 @@ process_g_packet (struct regcache *regcache) >> if (rsa->actual_register_packet_size == 0) >> rsa->actual_register_packet_size = buf_len; >> >> - /* If this is smaller than we guessed the 'g' packet would be, >> + /* If this is not same with we guessed the 'g' packet would be, >> update our records. A 'g' reply that doesn't include a register's >> value implies either that the register is not available, or that >> the 'p' packet must be used. */ >> - if (buf_len < 2 * rsa->sizeof_g_packet) >> + if (buf_len != 2 * rsa->sizeof_g_packet) >> { >> rsa->sizeof_g_packet = buf_len / 2; >> >> -- >> 1.9.3 >>