Bug 1170861

Created attachment 964916 [details]
File: backtrace

Created attachment 964917 [details]
File: cgroup

Created attachment 964918 [details]
File: core_backtrace

Created attachment 964919 [details]
File: dso_list

Created attachment 964920 [details]
File: environ

Created attachment 964921 [details]
File: limits

Created attachment 964922 [details]
File: maps

Created attachment 964923 [details]
File: open_fds

Created attachment 964925 [details]
File: proc_pid_status

Created attachment 964927 [details]
File: var_log_messages

Here is a self-contained reproducer:

#include <dlfcn.h>
#include <stdlib.h>
int main() {
  system("echo 'int foo() { return foo(); }' | gcc -x c -shared -fpic -o u.so -");
  void *d = dlopen("./u.so", RTLD_LAZY);
  if (d == NULL) {
    puts(dlerror());
    return 1;
  }
  unlink("u.so");
  int (*fp)(void) = (int(*)(void)) dlsym(d, "foo");
  return fp();
}


Run this under gdb and then just execute "p $pc".  Notice that the program crashes due to a stack overrun.  If you have this error in the executable itself it'll work fine.


The problem is that the DSO goes away before gdb reads the debug info.  This happens, for instance, with gcc's JIT.

For reference, here is the libgccjit RFE for working around this from the jit side:
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64206
(so that both bugs link to each other)

(In reply to Dave Malcolm from comment #12)
> For reference, here is the libgccjit RFE for working around this from the
> jit side:
>   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64206
> (so that both bugs link to each other)

FWIW libgccjit attempts to work around this, as of gcc r219395 (2015-01-09).

Another user experienced a similar problem:

Downloaded winff sources -> https://winff.googlecode.com/files/WinFF-1.5.2-source.tar.gz -> opened in Lazarus IDE -> tried to compile winff 

reporter:       libreport-2.3.0
backtrace_rating: 4
cmdline:        /usr/bin/gdb -silent -i mi -nx
crash_function: dump_core
executable:     /usr/bin/gdb
kernel:         3.18.3-201.fc21.x86_64
package:        gdb-7.8.2-38.fc21
reason:         gdb killed by SIGABRT
runlevel:       N 5
type:           CCpp
uid:            1000

[patch] Do not close BFDs, breaking deleted inferior shlibs
https://sourceware.org/ml/gdb-patches/2015-02/msg00367.html

Another user experienced a similar problem:

I debugged an user-mode-linux executable and i always seem to hit this assertion:

The assertion is in:
 409│ static int
 410│ thread_get_info_callback (const td_thrhandle_t *thp, void *argp)

 430│   if (inout->thread_info == NULL)
 431│     {
 432│       /* New thread.  Attach to it now (why wait?).  */
 433│       if (!have_threads (thread_ptid))
 434│         thread_db_find_new_threads_1 (thread_ptid);
 435│       else
 436│         attach_thread (thread_ptid, thp, &ti);
 437│       inout->thread_info = find_thread_ptid (thread_ptid);
 438├>      gdb_assert (inout->thread_info != NULL);
 439│     }
 440│
 441│   return 0;

(gdb) p	thread_ptid
$3 = {pid = 1454508, lwp = -1, tid = 0}

pid 1454508 is the user mode linux kernel exectuable file.

(gdb) p *inout
$5 = {thread_info = 0x0, thread_db_info	= 0x2662eb0}

(gdb) p *inout->thread_db_info
$7 = {next = 0x0, pid = 1454508, handle	= 0x277cd30, filename =	0x0, proc_handle = {ptid = {pid	= 1454508, lwp = 1454508, tid =	0}}, thread_agent = 0x264f440,	need_stale_parent_threads_check	= 0, td_create_bp_addr = 269203038288, td_death_bp_addr	= 269203038304,	td_init_p = 0x7f50b4f82920 <td_init>, td_ta_new_p = 0x7f50b4f82940 <td_ta_new>, td_ta_map_id2thr_p = 0x7f50b4f82b50 <td_ta_map_id2thr>, td_ta_map_lwp2thr_p =	0x7f50b4f82e50 <td_ta_map_lwp2thr>, td_ta_thr_iter_p = 0x7f50b4f83220 <td_ta_thr_iter>,	td_ta_event_addr_p = 0x7f50b4f842d0 <td_ta_event_addr>, td_ta_set_event_p = 0x7f50b4f84a60 <td_ta_set_event>, td_ta_clear_event_p = 0x7f50b4f84f00 <td_ta_clear_event>, td_ta_event_getmsg_p = 0x7f50b4f84c50 <td_ta_event_getmsg>, td_thr_validate_p	= 0x7f50b4f83ef0 <td_thr_validate>, td_thr_get_info_p = 0x7f50b4f83520 <td_thr_get_info>, td_thr_event_enable_p = 0x7f50b4f843b0 <td_thr_event_enable>, td_thr_tls_get_addr_p = 0x7f50b4f85220 <td_thr_tls_get_addr>, td_thr_tlsbase_p = 0x7f50b4f85120 <td_thr_tlsbase>}

any ideas what is going on here?

bug or feature?

I can provide more info about the failing gdb using another gdb :-)

reporter:       libreport-2.3.0
backtrace_rating: 4
cmdline:        gdb --nw --annotate=2 -x /home/thomas/.tgdb/a2_gdb_init ./linux
crash_function: dump_core
executable:     /usr/bin/gdb
kernel:         4.0.0
package:        gdb-7.8.2-38.fc21
reason:         gdb killed by SIGABRT
runlevel:       N 5
type:           CCpp
uid:            1000

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