Revert "malloc: tcache double free check" This reverts upstream commit bcdaad21d4635931d1bd3b54a7894276925d081d because it causes this regression: diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 96bf92533335036b..33574faab65628ff 100644 --- a/dlfcn/dlerror.c +++ b/dlfcn/dlerror.c @@ -198,10 +198,7 @@ check_free (struct dl_action_result *rec) Dl_info info; if (_dl_addr (check_free, &info, &map, NULL) != 0 && map->l_ns == 0) #endif - { - free ((char *) rec->errstring); - rec->errstring = NULL; - } + free ((char *) rec->errstring); } } diff --git a/malloc/Makefile b/malloc/Makefile index e6dfbfc14cb3d140..7d54bad866f63cb8 100644 --- a/malloc/Makefile +++ b/malloc/Makefile @@ -38,7 +38,6 @@ tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \ tst-malloc_info \ tst-malloc-too-large \ tst-malloc-stats-cancellation \ - tst-tcfree1 tst-tcfree2 \ tests-static := \ tst-interpose-static-nothread \ diff --git a/malloc/malloc.c b/malloc/malloc.c index f730d7a2ee496d36..6d7a6a8cabb4edbf 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2967,8 +2967,6 @@ mremap_chunk (mchunkptr p, size_t new_size) typedef struct tcache_entry { struct tcache_entry *next; - /* This field exists to detect double frees. */ - struct tcache_perthread_struct *key; } tcache_entry; /* There is one of these for each thread, which contains the @@ -2992,11 +2990,6 @@ tcache_put (mchunkptr chunk, size_t tc_idx) { tcache_entry *e = (tcache_entry *) chunk2mem (chunk); assert (tc_idx < TCACHE_MAX_BINS); - - /* Mark this chunk as "in the tcache" so the test in _int_free will - detect a double free. */ - e->key = tcache; - e->next = tcache->entries[tc_idx]; tcache->entries[tc_idx] = e; ++(tcache->counts[tc_idx]); @@ -3012,7 +3005,6 @@ tcache_get (size_t tc_idx) assert (tcache->entries[tc_idx] > 0); tcache->entries[tc_idx] = e->next; --(tcache->counts[tc_idx]); - e->key = NULL; return (void *) e; } @@ -4226,26 +4218,6 @@ _int_free (mstate av, mchunkptr p, int have_lock) { size_t tc_idx = csize2tidx (size); - /* Check to see if it's already in the tcache. */ - tcache_entry *e = (tcache_entry *) chunk2mem (p); - - /* This test succeeds on double free. However, we don't 100% - trust it (it also matches random payload data at a 1 in - 2^ chance), so verify it's not an unlikely coincidence - before aborting. */ - if (__glibc_unlikely (e->key == tcache && tcache)) - { - tcache_entry *tmp; - LIBC_PROBE (memory_tcache_double_free, 2, e, tc_idx); - for (tmp = tcache->entries[tc_idx]; - tmp; - tmp = tmp->next) - if (tmp == e) - malloc_printerr ("free(): double free detected in tcache 2"); - /* If we get here, it was a coincidence. We've wasted a few - cycles, but don't abort. */ - } - if (tcache && tc_idx < mp_.tcache_bins && tcache->counts[tc_idx] < mp_.tcache_count) diff --git a/malloc/tst-tcfree1.c b/malloc/tst-tcfree1.c deleted file mode 100644 index bc29375ce77304ac..0000000000000000 --- a/malloc/tst-tcfree1.c +++ /dev/null @@ -1,42 +0,0 @@ -/* Test that malloc tcache catches double free. - Copyright (C) 2018 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - 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 -#include -#include -#include - -static int -do_test (void) -{ - /* Do one allocation of any size that fits in tcache. */ - char * volatile x = malloc (32); - - free (x); // puts in tcache - free (x); // should abort - - printf("FAIL: tcache double free not detected\n"); - return 1; -} - -#define TEST_FUNCTION do_test -#define EXPECTED_SIGNAL SIGABRT -#include diff --git a/malloc/tst-tcfree2.c b/malloc/tst-tcfree2.c deleted file mode 100644 index 17f06bacd411c315..0000000000000000 --- a/malloc/tst-tcfree2.c +++ /dev/null @@ -1,48 +0,0 @@ -/* Test that malloc tcache catches double free. - Copyright (C) 2018 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - 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 -#include -#include -#include - -static int -do_test (void) -{ - char * volatile ptrs[20]; - int i; - - /* Allocate enough small chunks so that when we free them all, the tcache - is full, and the first one we freed is at the end of its linked list. */ -#define COUNT 20 - for (i=0; i diff --git a/manual/probes.texi b/manual/probes.texi index 0ea560ed78bcfd7e..ab2a3102bb350ef4 100644 --- a/manual/probes.texi +++ b/manual/probes.texi @@ -243,18 +243,6 @@ This probe is triggered when the value of this tunable. @end deftp -@deftp Probe memory_tcache_double_free (void *@var{$arg1}, int @var{$arg2}) -This probe is triggered when @code{free} determines that the memory -being freed has probably already been freed, and resides in the -per-thread cache. Note that there is an extremely unlikely chance -that this probe will trigger due to random payload data remaining in -the allocated memory matching the key used to detect double frees. -This probe actually indicates that an expensive linear search of the -tcache, looking for a double free, has happened. Argument @var{$arg1} -is the memory location as passed to @code{free}, Argument @var{$arg2} -is the tcache bin it resides in. -@end deftp - @node Mathematical Function Probes @section Mathematical Function Probes