From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Muller To: Eli Zaretskii , Mark Kettenis Cc: gdb-patches@sources.redhat.com Subject: [RFC] Possible bug with i386 watchpoints on several targets. Date: Fri, 30 Nov 2001 08:06:00 -0000 Message-ID: <4.2.0.58.20011130165213.016940c0@ics.u-strasbg.fr> References: <4.2.0.58.20011130161336.01698ae8@ics.u-strasbg.fr> <4.2.0.58.20011121124943.00a4a288@ics.u-strasbg.fr> <5567-Fri30Nov2001174510+0200-eliz@is.elta.co.il> X-SW-Source: 2001-11/msg00613.html Message-ID: <20011130080600.8-NHLRJEWPpy2FYb2E0LVgmhy5ZJVWZpjewdRSH_E08@z> At 16:45 30/11/2001 , Eli Zaretskii a écrit: > > Date: Fri, 30 Nov 2001 16:17:27 +0100 > > From: Pierre Muller > > > > What do we do about this? > > I proposed to add a call to i386_cleanup_dregs > > for all targets using the standard > > i386 hardware watchpoints, but > > Eli seems still not convinced by my reports.... > >You don't need to convince me (the port I'm responsible for _does_ >use i386_cleanup_dregs, after all ;-). You need to convince Mark >Kettenis. I'm sure that if you post a test program and a full recipe >to reproduce the problem, and then show the patch which makes the >problem go away, Mark will happily accept it. The way to check if the bug exist is easy: take gdb (5.1 or current snapshot) compiled with debug info and run ./gdb ./gdb on the newly generated executable. (preferabily in the compilation dir, which will ensure that you get (top-gdb) prompt for the debugger and (gdb) for the debuggee). use the following command (top-gdb) watch gdb_stdout (top-gdb) r Here you should get a stop due to the setting of gdb_stdout value. (top-gdb) cont you should now reach the debuggee command prompt, simply quit. (gdb) quit and rerun the same executable without any watchpoint modification. (top-gdb) run if the bug that I found on both win32 (without i386_cleanup_deregs call) and on current (a few days old) CVS for linux. You won't get any stop on the second run. The fix is not that obvious, because I am still a bit unclear about wher it should be put: the i386_cleanup_dregs should be called (in my opinion) both when a program is killed and when a program terminates normally. But linux does seem to use generic_mourn_inferior, so for this target it would probably require that we change this into a target specific function. PS: Eli, did you check the go32v2 target if you kill the program after the watchpoint is reached, sorry, I still can't get GDB to compile for djgpp on my win2000. Pierre Muller Institut Charles Sadron 6,rue Boussingault F 67083 STRASBOURG CEDEX (France) mailto:muller@ics.u-strasbg.fr Phone : (33)-3-88-41-40-07 Fax : (33)-3-88-41-40-99