gdb/gdb-infcall-sp-underflow.patch

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http://sourceware.org/ml/gdb-patches/2010-02/msg00515.html
Subject: [patch] infcall: Remove gdb_assert ($sp overflow)
Hi,
set $sp=0
call something()
->
../../gdb/infcall.c:521: internal-error: call_function_by_hand: Assertion
`(gdbarch_inner_than (gdbarch, 1, 2) && sp <= old_sp) || (gdbarch_inner_than
(gdbarch, 2, 1) && sp >= old_sp)' failed.
as $sp - frame == 0xffffsmth which is not lower than $sp.
It must not be gdb_assert(). It can be an error() but I left it just to do:
(gdb) set $sp=0
(gdb) call doubleit (1)
Cannot access memory at address 0xffffffffffffff78
(gdb) set $sp=-1
(gdb) call doubleit (1)
Cannot access memory at address 0xffffffffffffff68
Unaware how inconvenient is an intentional crash of the testcase on some
embedded/non-MMU systems.
No regressions on {x86_64,x86_64-m32,i686}-fedora12-linux-gnu.
Thanks,
Jan
gdb/
2010-02-19 Jan Kratochvil <jan.kratochvil@redhat.com>
* infcall.c (call_function_by_hand): Remove gdb_assert on sp and old_sp.
New comment.
gdb/testsuite/
2010-02-19 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.base/callfuncs.exp: New tests for $spval 0 and -1. Remove return.
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -518,10 +518,9 @@ call_function_by_hand (struct value *function, int nargs, struct value **args)
/* Stack grows up. */
sp = gdbarch_frame_align (gdbarch, old_sp + 1);
}
- gdb_assert ((gdbarch_inner_than (gdbarch, 1, 2)
- && sp <= old_sp)
- || (gdbarch_inner_than (gdbarch, 2, 1)
- && sp >= old_sp));
+ /* SP may have overflown address zero here from OLD_SP. Memory access
+ functions will probably fail in such case but that is a target's
+ problem. */
}
else
/* FIXME: cagney/2002-09-18: Hey, you loose!
--- a/gdb/testsuite/gdb.base/callfuncs.exp
+++ b/gdb/testsuite/gdb.base/callfuncs.exp
@@ -469,5 +469,18 @@ if {$old_reg_content == $new_reg_content} then {
fail "nested call dummies preserve register contents"
}
-return 0
+# GDB should not crash by internal error on $sp overflow during the inferior
+# call. It is OK it will stop on some: Cannot access memory at address 0x$hex.
+foreach spval {0 -1} {
+ set old_ldprefix $pf_prefix
+ lappend pf_prefix "sp=$spval:"
+
+ gdb_test {set $old_sp = $sp}
+ gdb_test "set \$sp = $spval"
+
+ gdb_test "call doubleit (1)"
+
+ gdb_test {set $sp = $old_sp}
+ set pf_prefix $old_ldprefix
+}