#8935: Obscure linker bug leads to crash in GHCi
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Reporter: simonmar | Owner: trommler
Type: bug | Status: patch
Priority: high | Milestone: 7.8.3
Component: Runtime System | Version: 7.8.1-rc2
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture: Unknown/Multiple
Type of failure: GHCi crash | Difficulty: Rocket Science
Test Case: | Blocked By:
Blocking: | Related Tickets:
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Comment (by simonmar):
`bar.c`:
{{{
static int bar = 1;
int _getbar(void)
{
return bar;
}
void _setbar(int x)
{
bar = x;
}
}}}
`foo.c`:
{{{
extern int _getbar(void);
extern void _setbar(int);
int getbar(void)
{
return _getbar();
}
int setbar(int x)
{
_setbar(x);
}
}}}
`test.c`:
{{{
#include
#include
#include
extern int getbar(void);
extern void setbar(int);
int main(int argc, char *argv[])
{
void *deflt, *hdl;
int (*pgetbar)(void);
int (*psetbar)(int);
setbar(2);
printf("getbar() = %d\n", getbar());
deflt = dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL);
if (deflt == NULL) {
printf("%s\n", dlerror());
exit(1);
}
pgetbar = dlsym(deflt, "getbar");
printf("dlsym(deflt, \"getbar\") = %p, pgetbar() = %d\n", pgetbar,
(*pgetbar)());
hdl = dlopen("libbar.so", RTLD_LOCAL | RTLD_LAZY);
if (hdl == NULL) {
printf("%s\n", dlerror());
exit(1);
}
pgetbar = dlsym(hdl, "_getbar");
psetbar = dlsym(hdl, "_setbar");
printf("dlsym(deflt, \"_getbar\") = %p, pgetbar() = %d\n", pgetbar,
(*pgetbar)());
(*psetbar)(3);
printf("(*psetbar)(3); pgetbar() = %d\n", (*pgetbar)());
hdl = dlopen("libfoo.so", RTLD_LOCAL | RTLD_LAZY);
if (hdl == NULL) {
printf("%s\n", dlerror());
exit(1);
}
pgetbar = dlsym(hdl, "getbar");
psetbar = dlsym(hdl, "setbar");
printf("dlsym(deflt, \"getbar\") = %p, pgetbar() = %d\n", pgetbar,
(*pgetbar)());
(*psetbar)(4);
printf("(*psetbar)(4); pgetbar() = %d\n", (*pgetbar)());
}
}}}
{{{
$ gcc -shared -fPIC bar.c -o libbar.so
$ gcc -shared -fPIC foo.c -o libfoo.so -L. -lbar
$ gcc test.c -L. -lfoo -lbar -ldl -g
$ LD_LIBRARY_PATH=. ./a.out
getbar() = 2
dlsym(deflt, "getbar") = 0x2b4660dcc61c, pgetbar() = 2
dlsym(deflt, "_getbar") = 0x2b46615a658c, pgetbar() = 2
(*psetbar)(3); pgetbar() = 3
dlsym(deflt, "getbar") = 0x2b4660dcc61c, pgetbar() = 3
(*psetbar)(4); pgetbar() = 4
}}}
--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8935#comment:47
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler
