From: Pedro Alves Date: Thu, 6 Jul 2023 14:05:11 +0000 (+0100) Subject: Fix Solaris regression (PR tdep/30252) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b2ad7bb9e6a012699195d3eda9d40679c406ebdc;p=binutils-gdb.git Fix Solaris regression (PR tdep/30252) 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) /root/binutils-gdb/gdb/procfs.c:2187 0xcf6da7 sol_thread_target::wait(ptid_t, target_waitstatus*, enum_flags) /root/binutils-gdb/gdb/sol-thread.c:442 0xd73711 target_wait(ptid_t, target_waitstatus*, enum_flags) /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 Tested-By: Marcel Telka Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30252 Change-Id: I6213c59b081d400a22e799ee621c2eff6dcafbf3 --- diff --git a/gdb/procfs.c b/gdb/procfs.c index 7990640963b..f0c2c2cf56c 100644 --- a/gdb/procfs.c +++ b/gdb/procfs.c @@ -589,6 +589,8 @@ static int proc_iterate_over_threads (procinfo *pi, int (*func) (procinfo *, procinfo *, void *), void *ptr); +static void proc_resume (procinfo *pi, ptid_t scope_ptid, + int step, enum gdb_signal signo); static void proc_warn (procinfo *pi, const char *func, int line) @@ -2119,7 +2121,7 @@ wait_again: gdb_printf (_("[%s exited]\n"), target_pid_to_str (retval).c_str ()); delete_thread (this->find_thread (retval)); - target_continue_no_signal (ptid); + proc_resume (pi, ptid, 0, GDB_SIGNAL_0); goto wait_again; } else if (what == SYS_exit) @@ -2183,8 +2185,7 @@ wait_again: i, sysargs[i]); } - /* How to keep going without returning to wfi: */ - target_continue_no_signal (ptid); + proc_resume (pi, ptid, 0, GDB_SIGNAL_0); goto wait_again; } break; @@ -2217,7 +2218,7 @@ wait_again: if (!in_thread_list (this, temp_ptid)) add_thread (this, temp_ptid); - target_continue_no_signal (ptid); + proc_resume (pi, ptid, 0, GDB_SIGNAL_0); goto wait_again; } else if (what == SYS_lwp_exit) @@ -2249,7 +2250,7 @@ wait_again: i, sysargs[i]); } - target_continue_no_signal (ptid); + proc_resume (pi, ptid, 0, GDB_SIGNAL_0); goto wait_again; } break; @@ -2428,20 +2429,16 @@ invalidate_cache (procinfo *parent, procinfo *pi, void *ptr) return 0; } -/* Make the child process runnable. Normally we will then call - procfs_wait and wait for it to stop again (unless gdb is async). +/* Make child process PI runnable. If STEP is true, then arrange for the child to stop again after - executing a single instruction. If SIGNO is zero, then cancel any - pending signal; if non-zero, then arrange for the indicated signal - to be delivered to the child when it runs. If PID is -1, then - allow any child thread to run; if non-zero, then allow only the - indicated thread to run. (not implemented yet). */ + executing a single instruction. SCOPE_PTID, STEP and SIGNO are + like in the target_resume interface. */ -void -procfs_target::resume (ptid_t ptid, int step, enum gdb_signal signo) +static void +proc_resume (procinfo *pi, ptid_t scope_ptid, int step, enum gdb_signal signo) { - procinfo *pi, *thread; + procinfo *thread; int native_signo; /* FIXME: Check/reword. */ @@ -2453,10 +2450,6 @@ procfs_target::resume (ptid_t ptid, int step, enum gdb_signal signo) So basically PR_STEP is the sole argument that must be passed to proc_run_process. */ - /* Find procinfo for main process. */ - pi = find_procinfo_or_die (inferior_ptid.pid (), 0); - - /* First cut: ignore pid argument. */ errno = 0; /* Convert signal to host numbering. */ @@ -2473,11 +2466,11 @@ procfs_target::resume (ptid_t ptid, int step, enum gdb_signal signo) /* Void the process procinfo's caches. */ invalidate_cache (NULL, pi, NULL); - if (ptid.pid () != -1) + if (scope_ptid.pid () != -1) { /* Resume a specific thread, presumably suppressing the others. */ - thread = find_procinfo (ptid.pid (), ptid.lwp ()); + thread = find_procinfo (scope_ptid.pid (), scope_ptid.lwp ()); if (thread != NULL) { if (thread->tid != 0) @@ -2502,6 +2495,17 @@ procfs_target::resume (ptid_t ptid, int step, enum gdb_signal signo) } } +/* Implementation of target_ops::resume. */ + +void +procfs_target::resume (ptid_t scope_ptid, int step, enum gdb_signal signo) +{ + /* Find procinfo for main process. */ + procinfo *pi = find_procinfo_or_die (inferior_ptid.pid (), 0); + + proc_resume (pi, scope_ptid, step, signo); +} + /* Set up to trace signals in the child process. */ void