From e42e5352d1d1e8a262178f606a5df3d0d988f78a Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Thu, 4 Feb 2016 15:09:09 +0000 Subject: [PATCH] waiting_for_stop_reply around remote_fileio_request Hi, I see this error when GDB connects with qemu, (gdb) n .... Sending packet: $vCont;c#a8...Ack Packet received: Ffstat,00000001,f6fff038 Cannot execute this command while the target is running. Use the "interrupt" command to stop the target and then try again. looks we don't set rs->waiting_for_stop_reply to zero before handle fileio request, #10 0x00000000005edb64 in target_write (len=64, offset=4143968312, buf=0x7fffffffd570 "\375\377\377\377", annex=0x0, object=TARGET_OBJECT_MEMORY, ops=) at /home/yao/SourceCode/gnu/gdb/git/gdb/target.c:1922 #11 target_write_memory (memaddr=memaddr@entry=4143968312, myaddr=myaddr@entry=0x7fffffffd6a0 "", len=len@entry=64) at /home/yao/SourceCode/gnu/gdb/git/gdb/target.c:1500 #12 0x00000000004b2b41 in remote_fileio_func_fstat (buf=0x127b258 "") at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:1037 #13 0x00000000004b1878 in do_remote_fileio_request (uiout=, buf_arg=buf_arg@entry=0x127b240) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:1204 #14 0x00000000005b8c7c in catch_exceptions_with_msg (func_uiout=, func=func@entry=0x4b1800 , func_args=func_args@entry=0x127b240, gdberrmsg=gdberrmsg@entry=0x0, mask=mask@entry=RETURN_MASK_ALL) at /home/yao/SourceCode/gnu/gdb/git/gdb/exceptions.c:187 #15 0x00000000005b8dea in catch_exceptions (uiout=, func=func@entry=0x4b1800 , func_args=func_args@entry=0x127b240, mask=mask@entry=RETURN_MASK_ALL) at /home/yao/SourceCode/gnu/gdb/git/gdb/exceptions.c:167 #16 0x00000000004b2fff in remote_fileio_request (buf=0x127b240 "Xf6fff038,0:", ctrlc_pending_p=0) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:1255 #17 0x0000000000496f12 in remote_wait_as (ptid=..., status=0x7fffffffdb20, options=1) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote.c:6997 however, we did set rs->waiting_for_stop_reply to zero before Luis's patch https://sourceware.org/ml/gdb-patches/2015-10/msg00336.html In fact, Luis's patch v1 https://sourceware.org/ml/gdb-patches/2015-08/msg00809.html is about setting rs->waiting_for_stop_reply back to one after remote_fileio_request, which is correct. However during the review, the patch is changed and ends up with "not setting rs->waiting_for_stop_reply to zero". I manually test GDB, but I don't have a way to run regression tests. gdb: 2016-02-04 Yao Qi * remote.c (remote_wait_as): Set rs->waiting_for_stop_reply to 0 before handling 'F' and set it back afterwards. --- gdb/ChangeLog | 5 +++++ gdb/remote.c | 8 ++++++++ 2 files changed, 13 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 829a48c..a2b0d39 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2016-02-04 Yao Qi + + * remote.c (remote_wait_as): Set rs->waiting_for_stop_reply to + 0 before handling 'F' and set it back afterwards. + 2016-02-02 Simon Marchi * ui-out.c (MAX_UI_OUT_LEVELS): Remove. diff --git a/gdb/remote.c b/gdb/remote.c index 8831b50..b1af8aa 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -6984,8 +6984,16 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status, int options) status->value.sig = GDB_SIGNAL_0; break; case 'F': /* File-I/O request. */ + /* GDB may access the inferior memory while handling the File-I/O + request, but we don't want GDB accessing memory while waiting + for a stop reply. See the comments in putpkt_binary. Set + waiting_for_stop_reply to 0 temporarily. */ + rs->waiting_for_stop_reply = 0; remote_fileio_request (buf, rs->ctrlc_pending_p); rs->ctrlc_pending_p = 0; + /* GDB handled the File-I/O request, and the target is running + again. Keep waiting for events. */ + rs->waiting_for_stop_reply = 1; break; case 'N': case 'T': case 'S': case 'X': case 'W': { -- 2.7.4