diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | dlfcn/dlerror.c | 5 | ||||
| -rw-r--r-- | malloc/Makefile | 1 | ||||
| -rw-r--r-- | malloc/malloc.c | 28 | ||||
| -rw-r--r-- | malloc/tst-tcfree1.c | 42 | ||||
| -rw-r--r-- | malloc/tst-tcfree2.c | 48 | ||||
| -rw-r--r-- | manual/probes.texi | 12 |
7 files changed, 1 insertions, 147 deletions
@@ -1,15 +1,3 @@ -2018-11-20 DJ Delorie <dj@redhat.com> - - * malloc/malloc.c (tcache_entry): Add key field. - (tcache_put): Set it. - (tcache_get): Likewise. - (_int_free): Check for double free in tcache. - * malloc/tst-tcfree1.c: New. - * malloc/tst-tcfree2.c: New. - * malloc/Makefile: Run the new tests. - * manual/probes.texi: Document memory_tcache_double_free probe. - - * dlfcn/dlerror.c (check_free): Prevent double frees. 2018-11-19 Florian Weimer <fweimer@redhat.com> support: Print timestamps in timeout handler. diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 96bf925333..33574faab6 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 e6dfbfc14c..7d54bad866 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 6be2573868..47795601c8 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2888,8 +2888,6 @@ 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 @@ -2913,11 +2911,6 @@ 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]); @@ -2933,7 +2926,6 @@ 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; } @@ -4174,26 +4166,6 @@ _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^<size_t> 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 bc29375ce7..0000000000 --- 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 - <http://www.gnu.org/licenses/>. */ - -#include <errno.h> -#include <error.h> -#include <limits.h> -#include <malloc.h> -#include <stdlib.h> -#include <stdio.h> -#include <sys/signal.h> - -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 <support/test-driver.c> diff --git a/malloc/tst-tcfree2.c b/malloc/tst-tcfree2.c deleted file mode 100644 index 17f06bacd4..0000000000 --- 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 - <http://www.gnu.org/licenses/>. */ - -#include <errno.h> -#include <error.h> -#include <limits.h> -#include <malloc.h> -#include <stdlib.h> -#include <stdio.h> -#include <sys/signal.h> - -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<COUNT; i++) - ptrs[i] = malloc (20); - for (i=0; i<COUNT; i++) - free (ptrs[i]); - free (ptrs[0]); - - printf("FAIL: tcache double free\n"); - return 1; -} - -#define TEST_FUNCTION do_test -#define EXPECTED_SIGNAL SIGABRT -#include <support/test-driver.c> diff --git a/manual/probes.texi b/manual/probes.texi index 0ea560ed78..ab2a3102bb 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 |