Pedro Alves
b2ad7bb9e6
PR tdep/30252 reports that using GDB on Solaris fails an assertion in
target_resume:
target.c:2648: internal-error: target_resume: Assertion `inferior_ptid != null_ptid' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
The backtrace, after running it through c++filt, looks like:
----- Backtrace -----
0xa18914 gdb_internal_backtrace_1
/root/binutils-gdb/gdb/bt-utils.c:122
0xa18914 gdb_internal_backtrace()
/root/binutils-gdb/gdb/bt-utils.c:168
0xdec834 internal_vproblem
/root/binutils-gdb/gdb/utils.c:401
0xdecad8 internal_verror(char const*, int, char const*, __va_list_tag*)
/root/binutils-gdb/gdb/utils.c:481
0xf3638c internal_error_loc(char const*, int, char const*, ...)
/root/binutils-gdb/gdbsupport/errors.cc:58
0xd70580 target_resume(ptid_t, int, gdb_signal)
/root/binutils-gdb/gdb/target.c:2648
0xc59e85 procfs_target::wait(ptid_t, target_waitstatus*, enum_flags<target_wait_flag>)
/root/binutils-gdb/gdb/procfs.c:2187
0xcf6da7 sol_thread_target::wait(ptid_t, target_waitstatus*, enum_flags<target_wait_flag>)
/root/binutils-gdb/gdb/sol-thread.c:442
0xd73711 target_wait(ptid_t, target_waitstatus*, enum_flags<target_wait_flag>)
/root/binutils-gdb/gdb/target.c:2586
...
The problem is that the procfs backend, while inside target_wait,
called target_resume without switching to the leader thread of that
resumption.
The target_resume interface is:
/* Resume execution (or prepare for execution) of the current thread
(INFERIOR_PTID), while optionally letting other threads of the
current process or all processes run free.
...
Thus calling target_resume with inferior_ptid == null_ptid is bogus.
target_wait (which leads to procfs_target::wait on Solaris) is called
with inferior_ptid == null_ptid on entry exactly to help catch such
bogus uses.
From the backtrace, it seems that the relevant line in question is
procfs.c:2187:
2186 /* How to keep going without returning to wfi: */
2187 target_continue_no_signal (ptid);
2188 goto wait_again;
target_continue_no_signal is a small wrapper around target_resume,
which would make sense.
The fix is to not call target_resume or go via the target stack at
all. Instead, factor out a new proc_resume function out of
procfs_target::resume, and call that. The new function does not rely
on inferior_ptid.
I've not been able to test it myself, but Petr confirmed it fixes the
assertion failure with his test case, and Marcel Telka also confirmed
it solves the problem.
Tested-By: Petr Šumbera <petr.sumbera@oracle.com>
Tested-By: Marcel Telka <marcel@telka.sk>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30252
Change-Id: I6213c59b081d400a22e799ee621c2eff6dcafbf3
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