On Sat, Mar 13, 2021 at 4:21 PM Eli Zaretskii wrote: > > From: Pip Cet > > Date: Sat, 13 Mar 2021 15:45:52 +0000 > > Cc: Andrea Corallo , 47067@debbugs.gnu.org > > > > On Sat, Mar 13, 2021 at 3:27 PM Eli Zaretskii wrote: > > > > > It's nowhere in the C backtrace, only its caller > > > > > > > > But it was in one of the previous backtraces? > > > > > > Too many moons ago. The ABI was bumped since then, and so did the > > > *.eln files. > > > > The code you pasted matches c-beginning-of-statement-1, and so does > > the Lisp backtrace, so I would suggest we go with it... > > I don't know how to go with it: the backtrace is truncated (for > reasons I don't yet understand) before it gets to it. I'm pretty sure the first ?? is c-beginning-of-stmt-1. It's a function with five arguments, at least. > > > > So EDI is bunk at this point. Can you go back a bit further to where > > > > it's initialized? > > > > > > Sorry, I don't understand: I gave you the disassembly of 512 bytes > > > before, isn't that enough to see where EDI is assigned the value? Or > > > what do you mean by "go back"? > > > > It's not enough, no. we're looking for an insn of the form mov XXX, > > %edi or lea XXX, %edi, or anything like that. > > I went back 4KB, and the only two instructions that write into EDI are It's a long function, that might not have been enough. > the following: > > 0x09e3159d: mov -0x100(%ebp),%edi > 0x09e31c71: mov 0x9f37b9c,%edi > > > I'm suspicious because EDI is a register variable that is clobbered > > somehow right after a setjmp returned. Which setjmp implementation are > > you using? > > Not sure how to answer that. AFAIK, it's a setjmp from the MS runtime. So not some mingw wrapper for it? I just checked the only "mingw"-like sources I could find, and they don't appear to use the frame pointer argument properly... > > Is it possible that you're on Windows, but unlike other Windows > > setjmps, it's unsafe to call your setjmp through a function pointer? > > How do I tell? Well, you could just apply this untested patch, fix any obvious compile errors I might not have spotted, and try to reproduce it. I'm not currently on a Windows (or x86) machine, so it's a bit hard for me to test... > And why I never had any problems with setjmp elsewhere in Emacs, > although we use it all the time in keyboard.c and elsewhere? It's only natively-compiled code that attempts to call setjmp through a function pointer. This was fixed in the POSIX case, but I didn't touch the Windows code because I assumed that they used the extra argument in their non-standard API to do this right... > Here's an interesting factoid: while most addresses in the backtraces > I see with this recipe are identical from run to run, the 'fun' > arguments of funcall_lambda's aren't. Compare the backtrace I sent 3 > messages ago with this one: > > #0 0x01236964 in arithcompare_driver (nargs=2, args=0x28, > comparison=ARITH_LESS) at data.c:2673 > #1 0x01236a3c in Flss (nargs=2, args=0x28) at data.c:2691 > #2 0x09e32285 in ?? () > #3 0x01261a74 in funcall_lambda (fun=XIL(0xa000000007650188), nargs=5, > arg_vector=0x826a08) at eval.c:3292 > #4 0x012603c9 in Ffuncall (nargs=6, args=0x826a00) at eval.c:3013 > #5 0x09ea0dbf in ?? () > #6 0x012603c9 in Ffuncall (nargs=1, args=0x826bd8) at eval.c:3013 > #7 0x09e8e041 in ?? () > #8 0x01261a74 in funcall_lambda (fun=XIL(0xa00000000778d5b8), nargs=1, > arg_vector=0x826db8) at eval.c:3292 > #9 0x012603c9 in Ffuncall (nargs=2, args=0x826db0) at eval.c:3013 > #10 0x70895b36 in F632d666f6e742d6c6f636b2d6375742d6f66662d6465636c617261746f7273_c_font_lock_cut_off_declarators_0 () > from d:\usr\eli\.emacs.d\eln-cache\28.0.50-7d88f6c1\cc-fonts-d7d8a7f5-b7c359cd.eln > #11 0x01261a74 in funcall_lambda (fun=XIL(0xa000000007785f78), nargs=1, > arg_vector=0x827050) at eval.c:3292 > #12 0x012603c9 in Ffuncall (nargs=2, args=0x827048) at eval.c:3013 > #13 0x068daf93 in ?? () > #14 0x012dea14 in helper_save_restriction () at comp.c:4575 > #15 0x0122eb86 in wrong_type_argument (predicate=XIL(0x892404890c245c89), > value=XIL(0x8244c89e45d8be0)) at data.c:143 > Backtrace stopped: previous frame inner to this frame (corrupt stack?) > > Note how arguments to Funcall's are the same, whereas arguments to > funcall_lambda's aren't. Even the garbage in the 2 arguments to > wrong_type_argument are identical. Which non-stack addresses are invariant in that backtrace? > Sounds like something is uninitialized somewhere? Hmm... Maybe... Pip