honggyukim
commented
5 years ago Here is gdb output.
# gdb -q --args `which uftrace` record -l /usr/bin/qml-runner --main hello.qml
Reading symbols from /usr/bin/uftrace...done.
(gdb) r
Starting program: /usr/bin/uftrace record -l /usr/bin/qml-runner --main hello.qml
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
[Attaching after process 9950 fork to child process 9958]
[New inferior 2 (process 9958)]
[Detaching after fork from parent process 9950]
[Inferior 1 (process 9950) detached]
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
process 9958 is executing new program: /usr/bin/qml-runner
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
...
Thread 2.1 "qml-runner" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 9958]
0x76fe6940 in _dl_signal_cexception (errcode=0, exception=0x768248dc <QQmlMemoryScope::state>,
occasion=0x76ffe900 <__stack_chk_guard> "") at dl-error-skeleton.c:148
148 dl-error-skeleton.c: No such file or directory.
(gdb) bt
#0 0x76fe6940 in _dl_signal_cexception (errcode=0, exception=0x768248dc <QQmlMemoryScope::state>,
occasion=0x76ffe900 <__stack_chk_guard> "") at dl-error-skeleton.c:148
#1 0x7681dcd0 in ?? () from /usr/lib/libQt5Qml.so.5
Backtrace stopped: previous frame identical to this frame (corrupt stack?)Here is glibc source code.
$ dl-error-skeleton.c
...
60 #if DL_ERROR_BOOTSTRAP
61 /* This points to a function which is called when an continuable error is
62 received. Unlike the handling of `catch' this function may return.
63 The arguments will be the `errstring' and `objname'.
64
65 Since this functionality is not used in normal programs (only in ld.so)
66 we do not care about multi-threaded programs here. We keep this as a
67 global variable. */
68 static receiver_fct receiver;
69 #endif /* DL_ERROR_BOOTSTRAP */
...
129 #if DL_ERROR_BOOTSTRAP
130 void
131 _dl_signal_cexception (int errcode, struct dl_exception *exception,
132 const char *occasion)
133 {
134 if (__builtin_expect (GLRO(dl_debug_mask)
135 & ~(DL_DEBUG_STATISTICS|DL_DEBUG_PRELINK), 0))
136 _dl_debug_printf ("%s: error: %s: %s (%s)\n",
137 exception->objname, occasion,
138 exception->errstring, receiver ? "continued" : "fatal");
139
140 if (receiver)
141 {
142 /* We are inside _dl_receive_error. Call the user supplied
143 handler and resume the work. The receiver will still be
144 installed. */
145 (*receiver) (errcode, exception->objname, exception->errstring);
146 }
147 else
148 _dl_signal_exception (errcode, exception, occasion);
149 }The possibly related code that call _dl_signal_cexception is as follows:
$ cat dl-lookup.c
...
/* Search loaded objects' symbol tables for a definition of the symbol
UNDEF_NAME, perhaps with a requested version for the symbol.
We must never have calls to the audit functions inside this function
or in any function which gets called. If this would happen the audit
code might create a thread which can throw off all the scope locking. */
lookup_t
_dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
const ElfW(Sym) **ref,
struct r_scope_elem *symbol_scope[],
const struct r_found_version *version,
int type_class, int flags, struct link_map *skip_map)
{
...
/* Search the relevant loaded objects for a definition. */
for (size_t start = i; *scope != NULL; start = 0, ++scope)
{
int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
¤t_value, *scope, start, version, flags,
skip_map, type_class, undef_map);
if (res > 0)
break;
if (__glibc_unlikely (res < 0) && skip_map == NULL)
{
/* Oh, oh. The file named in the relocation entry does not
contain the needed symbol. This code is never reached
for unversioned lookups. */
assert (version != NULL);
const char *reference_name = undef_map ? undef_map->l_name : "";
struct dl_exception exception;
/* XXX We cannot translate the message. */
_dl_exception_create_format
(&exception, DSO_FILENAME (reference_name),
"symbol %s version %s not defined in file %s"
" with link time reference%s",
undef_name, version->name, version->filename,
res == -2 ? " (no version symbols)" : "");
_dl_signal_cexception (0, &exception, N_("relocation error"));
_dl_exception_free (&exception);
*ref = NULL;
return 0;
}
}
if (__glibc_unlikely (current_value.s == NULL))
{
if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
&& !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED))
{
/* We could find no value for a strong reference. */
const char *reference_name = undef_map ? undef_map->l_name : "";
const char *versionstr = version ? ", version " : "";
const char *versionname = (version && version->name
? version->name : "");
struct dl_exception exception;
/* XXX We cannot translate the message. */
_dl_exception_create_format
(&exception, DSO_FILENAME (reference_name),
"undefined symbol: %s%s%s",
undef_name, versionstr, versionname);
_dl_signal_cexception (0, &exception, N_("symbol lookup error"));
_dl_exception_free (&exception);
}
*ref = NULL;
return 0;
}
...
}
It gets segfault when running
qml-runnerin ARM 32-bit environment.The replay output is as follows:
As above,
dlsymand_Uarm_stepmight be some problematic points. It might also be related to auto recover issue as well.