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Avoid potential deadlock in mtrace

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The _dl_addr function might have to call malloc which would lead
to a deadlock.  Avoid by calling _dl_addr early.
This commit is contained in:
Ulrich Drepper
2011-05-16 00:58:33 -04:00
parent 6ce7537960
commit 56e5eb4619
3 changed files with 59 additions and 31 deletions
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64
malloc/mtrace.c
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@ -79,46 +79,59 @@ tr_break ()
}
libc_hidden_def (tr_break)
static void tr_where (const __ptr_t) __THROW internal_function;
static void tr_where (const __ptr_t, Dl_info *) __THROW internal_function;
static void
internal_function
tr_where (caller)
tr_where (caller, info)
const __ptr_t caller;
Dl_info *info;
{
if (caller != NULL)
{
#ifdef HAVE_ELF
Dl_info info;
if (_dl_addr (caller, &info, NULL, NULL))
if (info != NULL)
{
char *buf = (char *) "";
if (info.dli_sname != NULL)
if (info->dli_sname != NULL)
{
size_t len = strlen (info.dli_sname);
size_t len = strlen (info->dli_sname);
buf = alloca (len + 6 + 2 * sizeof (void *));
buf[0] = '(';
__stpcpy (_fitoa (caller >= (const __ptr_t) info.dli_saddr
? caller - (const __ptr_t) info.dli_saddr
: (const __ptr_t) info.dli_saddr - caller,
__stpcpy (__mempcpy (buf + 1, info.dli_sname,
__stpcpy (_fitoa (caller >= (const __ptr_t) info->dli_saddr
? caller - (const __ptr_t) info->dli_saddr
: (const __ptr_t) info->dli_saddr - caller,
__stpcpy (__mempcpy (buf + 1, info->dli_sname,
len),
caller >= (__ptr_t) info.dli_saddr
caller >= (__ptr_t) info->dli_saddr
? "+0x" : "-0x"),
16, 0),
")");
}
fprintf (mallstream, "@ %s%s%s[%p] ",
info.dli_fname ?: "", info.dli_fname ? ":" : "",
info->dli_fname ?: "", info->dli_fname ? ":" : "",
buf, caller);
}
else
#endif
fprintf (mallstream, "@ [%p] ", caller);
}
}
static Dl_info *
lock_and_info (const __ptr_t caller, Dl_info *mem)
{
if (caller == NULL)
return NULL;
Dl_info *res = _dl_addr (caller, mem, NULL, NULL) ? mem : NULL;
__libc_lock_lock (lock);
return res;
}
static void tr_freehook (__ptr_t, const __ptr_t) __THROW;
static void
tr_freehook (ptr, caller)
@ -127,8 +140,10 @@ tr_freehook (ptr, caller)
{
if (ptr == NULL)
return;
__libc_lock_lock (lock);
tr_where (caller);
Dl_info mem;
Dl_info *info = lock_and_info (caller, &mem);
tr_where (caller, info);
/* Be sure to print it first. */
fprintf (mallstream, "- %p\n", ptr);
__libc_lock_unlock (lock);
@ -152,7 +167,8 @@ tr_mallochook (size, caller)
{
__ptr_t hdr;
__libc_lock_lock (lock);
Dl_info mem;
Dl_info *info = lock_and_info (caller, &mem);
__malloc_hook = tr_old_malloc_hook;
if (tr_old_malloc_hook != NULL)
@ -161,7 +177,7 @@ tr_mallochook (size, caller)
hdr = (__ptr_t) malloc (size);
__malloc_hook = tr_mallochook;
tr_where (caller);
tr_where (caller, info);
/* We could be printing a NULL here; that's OK. */
fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size);
@ -186,7 +202,8 @@ tr_reallochook (ptr, size, caller)
if (ptr == mallwatch)
tr_break ();
__libc_lock_lock (lock);
Dl_info mem;
Dl_info *info = lock_and_info (caller, &mem);
__free_hook = tr_old_free_hook;
__malloc_hook = tr_old_malloc_hook;
@ -199,7 +216,7 @@ tr_reallochook (ptr, size, caller)
__malloc_hook = tr_mallochook;
__realloc_hook = tr_reallochook;
tr_where (caller);
tr_where (caller, info);
if (hdr == NULL)
/* Failed realloc. */
fprintf (mallstream, "! %p %#lx\n", ptr, (unsigned long int) size);
@ -208,7 +225,7 @@ tr_reallochook (ptr, size, caller)
else
{
fprintf (mallstream, "< %p\n", ptr);
tr_where (caller);
tr_where (caller, info);
fprintf (mallstream, "> %p %#lx\n", hdr, (unsigned long int) size);
}
@ -229,7 +246,8 @@ tr_memalignhook (alignment, size, caller)
{
__ptr_t hdr;
__libc_lock_lock (lock);
Dl_info mem;
Dl_info *info = lock_and_info (caller, &mem);
__memalign_hook = tr_old_memalign_hook;
__malloc_hook = tr_old_malloc_hook;
@ -240,7 +258,7 @@ tr_memalignhook (alignment, size, caller)
__memalign_hook = tr_memalignhook;
__malloc_hook = tr_mallochook;
tr_where (caller);
tr_where (caller, info);
/* We could be printing a NULL here; that's OK. */
fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size);