Always do locking when accessing streams (bug 15142, bug 14697) Now that abort no longer calls fflush there is no reason to avoid locking the stdio streams anywhere. This fixes a conformance issue and potential heap corruption during exit. The test nptl/tst-stdio1 is removed as that was expecting the problematic behaviour. Index: glibc-2.32/libio/genops.c =================================================================== --- glibc-2.32.orig/libio/genops.c +++ glibc-2.32/libio/genops.c @@ -682,7 +682,7 @@ _IO_adjust_column (unsigned start, const libc_hidden_def (_IO_adjust_column) int -_IO_flush_all_lockp (int do_lock) +_IO_flush_all (void) { int result = 0; FILE *fp; @@ -695,8 +695,7 @@ _IO_flush_all_lockp (int do_lock) for (fp = (FILE *) _IO_list_all; fp != NULL; fp = fp->_chain) { run_fp = fp; - if (do_lock) - _IO_flockfile (fp); + _IO_flockfile (fp); if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base) || (_IO_vtable_offset (fp) == 0 @@ -706,8 +705,7 @@ _IO_flush_all_lockp (int do_lock) && _IO_OVERFLOW (fp, EOF) == EOF) result = EOF; - if (do_lock) - _IO_funlockfile (fp); + _IO_funlockfile (fp); run_fp = NULL; } @@ -718,14 +716,6 @@ _IO_flush_all_lockp (int do_lock) return result; } - - -int -_IO_flush_all (void) -{ - /* We want locking. */ - return _IO_flush_all_lockp (1); -} libc_hidden_def (_IO_flush_all) void @@ -791,6 +781,9 @@ _IO_unbuffer_all (void) { int legacy = 0; + run_fp = fp; + _IO_flockfile (fp); + #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) if (__glibc_unlikely (_IO_vtable_offset (fp) != 0)) legacy = 1; @@ -800,18 +793,6 @@ _IO_unbuffer_all (void) /* Iff stream is un-orientated, it wasn't used. */ && (legacy || fp->_mode != 0)) { -#ifdef _IO_MTSAFE_IO - int cnt; -#define MAXTRIES 2 - for (cnt = 0; cnt < MAXTRIES; ++cnt) - if (fp->_lock == NULL || _IO_lock_trylock (*fp->_lock) == 0) - break; - else - /* Give the other thread time to finish up its use of the - stream. */ - __sched_yield (); -#endif - if (! legacy && ! dealloc_buffers && !(fp->_flags & _IO_USER_BUF)) { fp->_flags |= _IO_USER_BUF; @@ -825,17 +806,15 @@ _IO_unbuffer_all (void) if (! legacy && fp->_mode > 0) _IO_wsetb (fp, NULL, NULL, 0); - -#ifdef _IO_MTSAFE_IO - if (cnt < MAXTRIES && fp->_lock != NULL) - _IO_lock_unlock (*fp->_lock); -#endif } /* Make sure that never again the wide char functions can be used. */ if (! legacy) fp->_mode = -1; + + _IO_funlockfile (fp); + run_fp = NULL; } #ifdef _IO_MTSAFE_IO @@ -861,9 +840,7 @@ libc_freeres_fn (buffer_free) int _IO_cleanup (void) { - /* We do *not* want locking. Some threads might use streams but - that is their problem, we flush them underneath them. */ - int result = _IO_flush_all_lockp (0); + int result = _IO_flush_all (); /* We currently don't have a reliable mechanism for making sure that C++ static destructors are executed in the correct order. Index: glibc-2.32/libio/libioP.h =================================================================== --- glibc-2.32.orig/libio/libioP.h +++ glibc-2.32/libio/libioP.h @@ -487,7 +487,6 @@ extern int _IO_new_do_write (FILE *, con extern int _IO_old_do_write (FILE *, const char *, size_t); extern int _IO_wdo_write (FILE *, const wchar_t *, size_t); libc_hidden_proto (_IO_wdo_write) -extern int _IO_flush_all_lockp (int); extern int _IO_flush_all (void); libc_hidden_proto (_IO_flush_all) extern int _IO_cleanup (void); Index: glibc-2.32/sysdeps/pthread/Makefile =================================================================== --- glibc-2.32.orig/sysdeps/pthread/Makefile +++ glibc-2.32/sysdeps/pthread/Makefile @@ -99,7 +99,7 @@ tests += tst-cnd-basic tst-mtx-trylock t tst-signal4 tst-signal5 tst-signal6 tst-signal8 \ tst-spin1 tst-spin2 tst-spin3 tst-spin4 \ tst-stack1 \ - tst-stdio1 tst-stdio2 \ + tst-stdio2 \ tst-pt-sysconf \ tst-pt-tls1 tst-pt-tls2 \ tst-tsd1 tst-tsd2 tst-tsd5 tst-tsd6 \ Index: glibc-2.32/sysdeps/pthread/tst-stdio1.c =================================================================== --- glibc-2.32.orig/sysdeps/pthread/tst-stdio1.c +++ /dev/null @@ -1,56 +0,0 @@ -/* Copyright (C) 2002-2021 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper , 2002. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include -#include -#include - -static int do_test (void); - -#define TEST_FUNCTION do_test () -#include "../test-skeleton.c" - -static void *tf (void *a) -{ - flockfile (stdout); - /* This call should never return. */ - return a; -} - - -int -do_test (void) -{ - pthread_t th; - - flockfile (stdout); - - if (pthread_create (&th, NULL, tf, NULL) != 0) - { - write_message ("create failed\n"); - _exit (1); - } - - delayed_exit (1); - xpthread_join (th); - - puts ("join returned"); - - return 1; -}