From: Dmitry Antipov <dmantipov@yandex.ru>
To: Michael Welsh Duggan <md5i@md5i.com>,
Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: 18473@debbugs.gnu.org
Subject: bug#18473: 24.4.50; SEGFAULT when vconcatting more than 2048 vectors
Date: Mon, 15 Sep 2014 10:38:19 +0400 [thread overview]
Message-ID: <5416895B.4080807@yandex.ru> (raw)
In-Reply-To: <5415CC07.2010702@yandex.ru>
[-- Attachment #1: Type: text/plain, Size: 1469 bytes --]
On 09/14/2014 09:10 PM, Dmitry Antipov wrote:
> In eval.c:
>
> 2134 else if (XSUBR (fun)->max_args == MANY)
> 2135 {
> 2136 /* Pass a vector of evaluated arguments. */
> 2137 Lisp_Object *vals;
> 2138 ptrdiff_t argnum = 0;
> 2139 USE_SAFE_ALLOCA;
> 2140
> 2141 SAFE_ALLOCA_LISP (vals, XINT (numargs));
> 2142
> 2143 GCPRO3 (args_left, fun, fun);
> 2144 gcpro3.var = vals;
> 2145 gcpro3.nvars = 0;
> 2146
> 2147 while (!NILP (args_left))
> 2148 {
> 2149 vals[argnum++] = eval_sub (Fcar (args_left));
> 2150 args_left = Fcdr (args_left);
> 2151 gcpro3.nvars = argnum;
> 2152 }
> 2153
> 2154 set_backtrace_args (specpdl_ptr - 1, vals);
> 2155 set_backtrace_nargs (specpdl_ptr - 1, XINT (numargs));
> 2156
> 2157 val = (XSUBR (fun)->function.aMANY) (XINT (numargs), vals);
> 2158 UNGCPRO;
> 2159 SAFE_FREE ();
> 2160 }
>
> At 2141, if numargs is > 2047 (and so allocation size exceeds MAX_ALLOCA on
> a 64-bit system), SAFE_ALLOCA_LISP pushes an entry of type SPECPDL_UNWIND to
> specpdl stack. At line 2154, set_backtrace_args modifies this entry assuming
> SPECPDL_BACKTRACE. Oops.
Michael, try this. Stefan, please review.
Dmitry
[-- Attachment #2: bug18473.patch --]
[-- Type: text/x-diff, Size: 1487 bytes --]
=== modified file 'src/eval.c'
--- src/eval.c 2014-09-02 06:29:01 +0000
+++ src/eval.c 2014-09-15 06:22:26 +0000
@@ -179,17 +179,11 @@
/* Functions to modify slots of backtrace records. */
static void
-set_backtrace_args (union specbinding *pdl, Lisp_Object *args)
+set_backtrace_args (union specbinding *pdl, Lisp_Object *args, ptrdiff_t nargs)
{
eassert (pdl->kind == SPECPDL_BACKTRACE);
pdl->bt.args = args;
-}
-
-static void
-set_backtrace_nargs (union specbinding *pdl, ptrdiff_t n)
-{
- eassert (pdl->kind == SPECPDL_BACKTRACE);
- pdl->bt.nargs = n;
+ pdl->bt.nargs = nargs;
}
static void
@@ -2151,8 +2145,7 @@
gcpro3.nvars = argnum;
}
- set_backtrace_args (specpdl_ptr - 1, vals);
- set_backtrace_nargs (specpdl_ptr - 1, XINT (numargs));
+ set_backtrace_args (backtrace_top (), vals, XINT (numargs));
val = (XSUBR (fun)->function.aMANY) (XINT (numargs), vals);
UNGCPRO;
@@ -2173,8 +2166,7 @@
UNGCPRO;
- set_backtrace_args (specpdl_ptr - 1, argvals);
- set_backtrace_nargs (specpdl_ptr - 1, XINT (numargs));
+ set_backtrace_args (backtrace_top (), argvals, XINT (numargs));
switch (i)
{
@@ -2919,8 +2911,8 @@
UNGCPRO;
- set_backtrace_args (specpdl_ptr - 1, arg_vector);
- set_backtrace_nargs (specpdl_ptr - 1, i);
+ set_backtrace_args (backtrace_top (), arg_vector, i);
+
tem = funcall_lambda (fun, numargs, arg_vector);
/* Do the debug-on-exit now, while arg_vector still exists. */
next prev parent reply other threads:[~2014-09-15 6:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-14 2:37 bug#18473: 24.4.50; SEGFAULT when vconcatting more than 2048 vectors Michael Welsh Duggan
2014-09-14 17:10 ` Dmitry Antipov
2014-09-15 6:38 ` Dmitry Antipov [this message]
2014-09-15 13:09 ` Stefan Monnier
2014-09-15 15:04 ` Dmitry Antipov
2014-09-15 19:15 ` Stefan Monnier
2014-09-16 4:19 ` Dmitry Antipov
2014-09-23 15:52 ` Paul Eggert
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