From 2827ab990aefbb0e53374199b875d98f116d6390 Mon Sep 17 00:00:00 2001 From: Carlos O'Donell Date: Fri, 22 Jun 2018 09:28:47 -0400 Subject: libc: Extend __libc_freeres framework (Bug 23329). The __libc_freeres framework does not extend to non-libc.so objects. This causes problems in general for valgrind and mtrace detecting unfreed objects in both libdl.so and libpthread.so. This change is a pre-requisite to properly moving the malloc hooks out of malloc since such a move now requires precise accounting of all allocated data before destructors are run. This commit adds a proper hook in libc.so.6 for both libdl.so and for libpthread.so, this ensures that shm-directory.c which uses freeit () to free memory is called properly. We also remove the nptl_freeres hook and fall back to using weak-ref-and-check idiom for a loaded libpthread.so, thus making this process similar for all DSOs. Lastly we follow best practice and use explicit free calls for both libdl.so and libpthread.so instead of the generic hook process which has undefined order. Tested on x86_64 with no regressions. Signed-off-by: DJ Delorie Signed-off-by: Carlos O'Donell --- ChangeLog | 48 +++++++++++++++++++ dlfcn/Makefile | 2 +- dlfcn/Versions | 1 + dlfcn/dlerror.c | 14 ++++++ dlfcn/dlfreeres.c | 29 ++++++++++++ dlfcn/sdlfreeres.c | 1 + include/dlfcn.h | 4 +- include/libc-symbols.h | 83 +++++++++++++++++++++++++++++---- include/set-hooks.h | 3 +- malloc/set-freeres.c | 15 ++++++ malloc/thread-freeres.c | 4 +- nptl/Makefile | 2 +- nptl/Versions | 1 + nptl/allocatestack.c | 12 +++-- nptl/libc_pthread_init.c | 8 ---- nptl/nptl-init.c | 15 ------ nptl/nptlfreeres.c | 31 ++++++++++++ nptl/pthreadP.h | 5 +- resolv/res-close.c | 1 + resolv/resolv_conf.c | 1 + string/strerror_l.c | 3 +- sunrpc/rpc_thread.c | 1 + sysdeps/mach/strerror_l.c | 3 +- sysdeps/nptl/pthread-functions.h | 1 - sysdeps/nptl/unwind-forcedunwind.c | 4 +- sysdeps/unix/sysv/linux/shm-directory.c | 6 +-- 26 files changed, 245 insertions(+), 53 deletions(-) create mode 100644 dlfcn/dlfreeres.c create mode 100644 dlfcn/sdlfreeres.c create mode 100644 nptl/nptlfreeres.c diff --git a/ChangeLog b/ChangeLog index 8d451c8..3371a9b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,51 @@ +2018-06-29 DJ Delorie + Carlos O'Donell + + [BZ #23329] + * include/libc-symbols.h: Comment the freeres framework. + * include/set-hooks.h: Include libc-symbols.h. Fix comment. + * dlfcn/Makefile (libdl-routines): Add dlfreeres. + * dlfcn/Versions (GLIBC_PRIVATE): Add __libdl_freeres. + * dlfcn/dlerror.c: Include libc-symbols.h + (__dlerror_main_freeres): New function. + * dlfcn/dlfreeres.c: New file. + * dlfcn/sdlfreeres.c: New file. + * include/dlfcn.h: Declare __dlerror_main_freeres. + * malloc/set-freeres.c: Declare __libdl_freeres, and + __libpthread_freeres. + (__libc_subfreeres): Call __libdl_freeres, and __libpthread_freeres if + the releavant libraries are loaded. + * malloc/thread-freeres.c: Add comments. + * nptl/Makefile (libpthread-routines): Add nptlfreeres. + * nptl/Version (GLIBC_PRIVATE): Add __libpthread_freeres. + * nptl/allocatestack.c (__nptl_free_stacks): New function. + (__free_stacks): Rename to... + (free_stacks): ...this. Mark static. + (queue_stack): Call free_stacks. + * nptl/libc_pthread_init.c [SHARED] (freeres_libpthread): Delete. + * nptl/nptl-init.c: Delete delcaration of nptl_freeres. + * sysdeps/nptl/pthread-functions.h (pthread_functions): Remove + ptr_freeres element from struct. + (pthread_functions): Remove .ptr_freeres from struct initializer. + [SHARED] (nptl_freeres): Remove. + * nptl/nptlfreeres.c: New file. + * nptl/pthreadP.h + [IS_IN (libpthread) && SHARED ] (__unwind_freeres): Rename to... + [IS_IN (libpthread)] (__nptl_unwind_freeres): ...this. Mark + attribute_hidden. + (__free_stacks): Rename to... + (__nptl_stacks_freeres): ...this. + (__shm_directory_freeres): Declare. + * nptl/unwind-forcedunwind.c (__unwind_freeres): Rename to... + (__nptl_unwind_freeres): ...this. + * resolv/res-close.c: Add comment. + * resolv/resolv_conf.c: Include libc-symbols.h. + * string/strerror_l.c: Include libc-symbols.h. + * sunrpc/rpc_thread.c: Include libc-symbols.h. + * sysdeps/mach/strerror_l.c: Inlcude libc-symbols.h + * sysdeps/unix/sysv/linux/shm-directory.c (freeit): Rename to... + [IS_IN (libpthread)] (__shm_directory_freeres): ...this. + 2018-06-29 Rajalakshmi Srinivasaraghavan * stdlib/tst-strfmon_l.c: Add tests for long double. diff --git a/dlfcn/Makefile b/dlfcn/Makefile index 56dcae0..34f9923 100644 --- a/dlfcn/Makefile +++ b/dlfcn/Makefile @@ -22,7 +22,7 @@ include ../Makeconfig headers := bits/dlfcn.h dlfcn.h extra-libs := libdl libdl-routines := dlopen dlclose dlsym dlvsym dlerror dladdr dladdr1 dlinfo \ - dlmopen dlfcn + dlmopen dlfcn dlfreeres routines := $(patsubst %,s%,$(filter-out dlfcn,$(libdl-routines))) elide-routines.os := $(routines) diff --git a/dlfcn/Versions b/dlfcn/Versions index 97902f0..1df6925 100644 --- a/dlfcn/Versions +++ b/dlfcn/Versions @@ -13,5 +13,6 @@ libdl { } GLIBC_PRIVATE { _dlfcn_hook; + __libdl_freeres; } } diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 04dce9d..33574fa 100644 --- a/dlfcn/dlerror.c +++ b/dlfcn/dlerror.c @@ -24,6 +24,7 @@ #include #include #include +#include #if !defined SHARED && IS_IN (libdl) @@ -222,6 +223,19 @@ free_key_mem (void *mem) # ifdef SHARED +/* Free the dlerror-related resources. */ +void +__dlerror_main_freeres (void) +{ + void *mem; + /* Free the global memory if used. */ + check_free (&last_result); + /* Free the TSD memory if used. */ + mem = __libc_getspecific (key); + if (mem != NULL) + free_key_mem (mem); +} + struct dlfcn_hook *_dlfcn_hook __attribute__((nocommon)); libdl_hidden_data_def (_dlfcn_hook) diff --git a/dlfcn/dlfreeres.c b/dlfcn/dlfreeres.c new file mode 100644 index 0000000..4004db0 --- /dev/null +++ b/dlfcn/dlfreeres.c @@ -0,0 +1,29 @@ +/* Clean up allocated libdl memory on demand. + 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 + +/* Free libdl.so resources. + Note: Caller ensures we are called only once. */ +void +__libdl_freeres (void) +{ + call_function_static_weak (__dlerror_main_freeres); +} diff --git a/dlfcn/sdlfreeres.c b/dlfcn/sdlfreeres.c new file mode 100644 index 0000000..7347672 --- /dev/null +++ b/dlfcn/sdlfreeres.c @@ -0,0 +1 @@ +#include "dlfreeres.c" diff --git a/include/dlfcn.h b/include/dlfcn.h index c231309..0dc57db 100644 --- a/include/dlfcn.h +++ b/include/dlfcn.h @@ -155,6 +155,8 @@ extern void __libc_register_dl_open_hook (struct link_map *map) extern void __libc_register_dlfcn_hook (struct link_map *map) attribute_hidden; #endif -#endif +extern void __dlerror_main_freeres (void) attribute_hidden; + +#endif #endif diff --git a/include/libc-symbols.h b/include/libc-symbols.h index 6137304..8b9273c 100644 --- a/include/libc-symbols.h +++ b/include/libc-symbols.h @@ -217,16 +217,6 @@ static const char __evoke_link_warning_##symbol[] \ __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \ = msg; -#define libc_freeres_ptr(decl) \ - __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \ - decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment))) -#define __libc_freeres_fn_section \ - __attribute__ ((section ("__libc_freeres_fn"))) - -#define libc_freeres_fn(name) \ - static void name (void) __attribute_used__ __libc_freeres_fn_section; \ - text_set_element (__libc_subfreeres, name); \ - static void name (void) /* A canned warning for sysdeps/stub functions. */ #define stub_warning(name) \ @@ -244,6 +234,79 @@ requires at runtime the shared libraries from the glibc version used \ for linking") #endif +/* Resource Freeing Hooks: + + Normally a process exits and the OS cleans up any allocated + memory. However, when tooling like mtrace or valgrind is monitoring + the process we need to free all resources that are part of the + process in order to provide the consistency required to track + memory leaks. + + A single public API exists and is __libc_freeres(), and this is used + by applications like valgrind to freee resouces. + + There are 3 cases: + + (a) __libc_freeres + + In this case all you need to do is define the freeing routine: + + foo.c: + libfoo_freeres_fn (foo_freeres) + { + complex_free (mem); + } + + This ensures the function is called at the right point to free + resources. + + (b) __libc_freeres_ptr + + The framework for (a) iterates over the list of pointers-to-free + in (b) and frees them. + + foo.c: + libc_freeres_ptr (static char *foo_buffer); + + Freeing these resources alaways happens last and is equivalent + to registering a function that does 'free (foo_buffer)'. + + (c) Explicit lists of free routines to call or objects to free. + + It is the intended goal to remove (a) and (b) which have some + non-determinism based on link order, and instead use explicit + lists of functions and frees to resolve cleanup ordering issues + and make it easy to debug and maintain. + + As of today the following subsystems use (c): + + Per-thread cleanup: + * malloc/thread-freeres.c + + libdl cleanup: + * dlfcn/dlfreeres.c + + libpthread cleanup: + * nptl/nptlfreeres.c + + So if you need any shutdown routines to run you should add them + directly to the appropriate subsystem's shutdown list. */ + +/* Resource pointers to free in libc.so. */ +#define libc_freeres_ptr(decl) \ + __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \ + decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment))) + +/* Resource freeing functions from libc.so go in this section. */ +#define __libc_freeres_fn_section \ + __attribute__ ((section ("__libc_freeres_fn"))) + +/* Resource freeing functions for libc.so. */ +#define libc_freeres_fn(name) \ + static void name (void) __attribute_used__ __libc_freeres_fn_section; \ + text_set_element (__libc_subfreeres, name); \ + static void name (void) + /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes alias to ORIGINAL, when the assembler supports such declarations (such as in ELF). diff --git a/include/set-hooks.h b/include/set-hooks.h index 0207656..b3bd8b4 100644 --- a/include/set-hooks.h +++ b/include/set-hooks.h @@ -22,11 +22,12 @@ #define __need_size_t #include #include +#include #ifdef symbol_set_define /* Define a hook variable called NAME. Functions put on this hook take arguments described by PROTO. Use `text_set_element (NAME, FUNCTION)' - from gnu-stabs.h to add a function to the hook. */ + from include/libc-symbols.h to add a function to the hook. */ # define DEFINE_HOOK(NAME, PROTO) \ typedef void __##NAME##_hook_function_t PROTO; \ diff --git a/malloc/set-freeres.c b/malloc/set-freeres.c index f4a0e7b..cda3684 100644 --- a/malloc/set-freeres.c +++ b/malloc/set-freeres.c @@ -26,6 +26,10 @@ DEFINE_HOOK (__libc_subfreeres, (void)); symbol_set_define (__libc_freeres_ptrs); +extern __attribute__ ((weak)) void __libdl_freeres (void); + +extern __attribute__ ((weak)) void __libpthread_freeres (void); + void __libc_freeres_fn_section __libc_freeres (void) { @@ -39,8 +43,19 @@ __libc_freeres (void) _IO_cleanup (); + /* We run the resource freeing after IO cleanup. */ RUN_HOOK (__libc_subfreeres, ()); + /* Call the libdl list of cleanup functions + (weak-ref-and-check). */ + if (&__libdl_freeres != NULL) + __libdl_freeres (); + + /* Call the libpthread list of cleanup functions + (weak-ref-and-check). */ + if (&__libpthread_freeres != NULL) + __libpthread_freeres (); + for (p = symbol_set_first_element (__libc_freeres_ptrs); !symbol_set_end_p (__libc_freeres_ptrs, p); ++p) free (*p); diff --git a/malloc/thread-freeres.c b/malloc/thread-freeres.c index 8902c84..a63b6c9 100644 --- a/malloc/thread-freeres.c +++ b/malloc/thread-freeres.c @@ -24,8 +24,8 @@ /* Thread shutdown function. Note that this function must be called for threads during shutdown for correctness reasons. Unlike - __libc_subfreeres, skipping calls to it is not a valid - optimization. */ + __libc_subfreeres, skipping calls to it is not a valid optimization. + This is called directly from pthread_create as the thread exits. */ void __libc_thread_freeres (void) { diff --git a/nptl/Makefile b/nptl/Makefile index 0f9c44a..2f2bb05 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -45,7 +45,7 @@ pthread-compat-wrappers = \ sigwait sigsuspend \ recvmsg sendmsg -libpthread-routines = nptl-init vars events version pt-interp \ +libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \ pthread_create pthread_exit pthread_detach \ pthread_join pthread_tryjoin pthread_timedjoin \ pthread_join_common \ diff --git a/nptl/Versions b/nptl/Versions index 0ae5def..b1c2da0 100644 --- a/nptl/Versions +++ b/nptl/Versions @@ -271,5 +271,6 @@ libpthread { __pthread_unwind; __pthread_get_minstack; __pthread_barrier_init; __pthread_barrier_wait; __shm_directory; + __libpthread_freeres; } } diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 9c10b99..f9e053f 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -251,8 +251,8 @@ get_cached_stack (size_t *sizep, void **memp) /* Free stacks until cache size is lower than LIMIT. */ -void -__free_stacks (size_t limit) +static void +free_stacks (size_t limit) { /* We reduce the size of the cache. Remove the last entries until the size is below the limit. */ @@ -288,6 +288,12 @@ __free_stacks (size_t limit) } } +/* Free all the stacks on cleanup. */ +void +__nptl_stacks_freeres (void) +{ + free_stacks (0); +} /* Add a stack frame which is not used anymore to the stack. Must be called with the cache lock held. */ @@ -302,7 +308,7 @@ queue_stack (struct pthread *stack) stack_cache_actsize += stack->stackblock_size; if (__glibc_unlikely (stack_cache_actsize > stack_cache_maxsize)) - __free_stacks (stack_cache_maxsize); + free_stacks (stack_cache_maxsize); } diff --git a/nptl/libc_pthread_init.c b/nptl/libc_pthread_init.c index f390480..e254ea2 100644 --- a/nptl/libc_pthread_init.c +++ b/nptl/libc_pthread_init.c @@ -77,11 +77,3 @@ __libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void), return &__libc_multiple_threads; #endif } - -#ifdef SHARED -libc_freeres_fn (freeres_libptread) -{ - if (__libc_pthread_functions_init) - PTHFCT_CALL (ptr_freeres, ()); -} -#endif diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 1d3790f..907411d 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -78,9 +78,6 @@ extern void __nptl_set_robust (struct pthread *); #ifdef SHARED -static void nptl_freeres (void); - - static const struct pthread_functions pthread_functions = { .ptr_pthread_attr_destroy = __pthread_attr_destroy, @@ -140,8 +137,6 @@ static const struct pthread_functions pthread_functions = # ifdef SIGSETXID .ptr__nptl_setxid = __nptl_setxid, # endif - /* For now only the stack cache needs to be freed. */ - .ptr_freeres = nptl_freeres, .ptr_set_robust = __nptl_set_robust }; # define ptr_pthread_functions &pthread_functions @@ -151,16 +146,6 @@ static const struct pthread_functions pthread_functions = #ifdef SHARED -/* This function is called indirectly from the freeres code in libc. */ -static void -__libc_freeres_fn_section -nptl_freeres (void) -{ - __unwind_freeres (); - __free_stacks (0); -} - - static #endif void diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c new file mode 100644 index 0000000..cfa54e1 --- /dev/null +++ b/nptl/nptlfreeres.c @@ -0,0 +1,31 @@ +/* Clean up allocated libpthread memory on demand. + 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 + +/* Free libpthread.so resources. + Note: Caller ensures we are called only once. */ +void +__libpthread_freeres (void) +{ + call_function_static_weak (__nptl_stacks_freeres); + call_function_static_weak (__shm_directory_freeres); + call_function_static_weak (__nptl_unwind_freeres); +} diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 075530c..3cba0b6 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -279,8 +279,8 @@ hidden_proto (__pthread_register_cancel) hidden_proto (__pthread_unregister_cancel) # ifdef SHARED extern void attribute_hidden pthread_cancel_init (void); -extern void __unwind_freeres (void); # endif +extern void __nptl_unwind_freeres (void) attribute_hidden; #endif @@ -597,7 +597,8 @@ extern int __nptl_setxid (struct xid_command *cmdp) attribute_hidden; extern void __nptl_set_robust (struct pthread *self); #endif -extern void __free_stacks (size_t limit) attribute_hidden; +extern void __nptl_stacks_freeres (void) attribute_hidden; +extern void __shm_directory_freeres (void) attribute_hidden; extern void __wait_lookup_done (void) attribute_hidden; diff --git a/resolv/res-close.c b/resolv/res-close.c index 38572b1..1c36dd5 100644 --- a/resolv/res-close.c +++ b/resolv/res-close.c @@ -140,4 +140,5 @@ __res_thread_freeres (void) /* Make sure we do a full re-initialization the next time. */ _res.options = 0; } +/* Also must be called when the main thread exits. */ text_set_element (__libc_subfreeres, __res_thread_freeres); diff --git a/resolv/resolv_conf.c b/resolv/resolv_conf.c index b4021ab..2f0ffbc 100644 --- a/resolv/resolv_conf.c +++ b/resolv/resolv_conf.c @@ -23,6 +23,7 @@ #include #include #include +#include /* _res._u._ext.__glibc_extension_index is used as an index into a struct resolv_conf_array object. The intent of this construction diff --git a/string/strerror_l.c b/string/strerror_l.c index 2a9c3b5..2a62b1f 100644 --- a/string/strerror_l.c +++ b/string/strerror_l.c @@ -21,7 +21,7 @@ #include #include #include - +#include static __thread char *last_value; @@ -56,7 +56,6 @@ strerror_l (int errnum, locale_t loc) return (char *) translate (_sys_errlist_internal[errnum], loc); } - void __strerror_thread_freeres (void) { diff --git a/sunrpc/rpc_thread.c b/sunrpc/rpc_thread.c index a65a90d..0abe6dc 100644 --- a/sunrpc/rpc_thread.c +++ b/sunrpc/rpc_thread.c @@ -5,6 +5,7 @@ #include #include #include +#include /* Variable used in non-threaded applications or for the first thread. */ diff --git a/sysdeps/mach/strerror_l.c b/sysdeps/mach/strerror_l.c index b9842cc..7111124 100644 --- a/sysdeps/mach/strerror_l.c +++ b/sysdeps/mach/strerror_l.c @@ -24,6 +24,7 @@ #include #include #include +#include static __thread char *last_value; @@ -86,7 +87,7 @@ strerror_l (int errnum, locale_t loc) return (char *) translate (es->subsystem[sub].codes[code], loc); } - +/* This is called when a thread is exiting to free the last_value string. */ void __strerror_thread_freeres (void) { diff --git a/sysdeps/nptl/pthread-functions.h b/sysdeps/nptl/pthread-functions.h index 53a4b38..fa10369 100644 --- a/sysdeps/nptl/pthread-functions.h +++ b/sysdeps/nptl/pthread-functions.h @@ -94,7 +94,6 @@ struct pthread_functions __attribute ((noreturn)) __cleanup_fct_attribute; void (*ptr__nptl_deallocate_tsd) (void); int (*ptr__nptl_setxid) (struct xid_command *); - void (*ptr_freeres) (void); void (*ptr_set_robust) (struct pthread *); }; diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c index 0621c80..5902fa4 100644 --- a/sysdeps/nptl/unwind-forcedunwind.c +++ b/sysdeps/nptl/unwind-forcedunwind.c @@ -79,9 +79,9 @@ pthread_cancel_init (void) libgcc_s_handle = handle; } +/* Register for cleanup in libpthread.so. */ void -__libc_freeres_fn_section -__unwind_freeres (void) +__nptl_unwind_freeres (void) { void *handle = libgcc_s_handle; if (handle != NULL) diff --git a/sysdeps/unix/sysv/linux/shm-directory.c b/sysdeps/unix/sysv/linux/shm-directory.c index c494d3f..6a7c7fd 100644 --- a/sysdeps/unix/sysv/linux/shm-directory.c +++ b/sysdeps/unix/sysv/linux/shm-directory.c @@ -135,13 +135,13 @@ __shm_directory (size_t *len) } #if IS_IN (libpthread) hidden_def (__shm_directory) -#endif - /* Make sure the table is freed if we want to free everything before exiting. */ -libc_freeres_fn (freeit) +void +__shm_directory_freeres (void) { if (mountpoint.dir != defaultdir) free (mountpoint.dir); } +#endif -- cgit v1.1