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author | Florian Weimer <fweimer@redhat.com> | 2021-12-09 09:49:32 +0100 |
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committer | Florian Weimer <fweimer@redhat.com> | 2021-12-09 09:49:32 +0100 |
commit | e3e589829d16af9f7e73c7b70f74f3c5d5003e45 (patch) | |
tree | f52c82410e4faed193d05dcf28c2586d6f83de16 /sysdeps | |
parent | 1d350aa06091211863e41169729cee1bca39f72f (diff) | |
download | glibc-e3e589829d16af9f7e73c7b70f74f3c5d5003e45.tar.gz glibc-e3e589829d16af9f7e73c7b70f74f3c5d5003e45.tar.xz glibc-e3e589829d16af9f7e73c7b70f74f3c5d5003e45.zip |
nptl: Add glibc.pthread.rseq tunable to control rseq registration
This tunable allows applications to register the rseq area instead of glibc. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/nptl/dl-tls_init_tp.c | 11 | ||||
-rw-r--r-- | sysdeps/nptl/dl-tunables.list | 6 | ||||
-rw-r--r-- | sysdeps/nptl/internaltypes.h | 1 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/Makefile | 8 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/rseq-internal.h | 19 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/tst-rseq-disable.c | 89 |
6 files changed, 126 insertions, 8 deletions
diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c index fedb876fdb..b39dfbff2c 100644 --- a/sysdeps/nptl/dl-tls_init_tp.c +++ b/sysdeps/nptl/dl-tls_init_tp.c @@ -23,6 +23,9 @@ #include <tls.h> #include <rseq-internal.h> +#define TUNABLE_NAMESPACE pthread +#include <dl-tunables.h> + #ifndef __ASSUME_SET_ROBUST_LIST bool __nptl_set_robust_list_avail; rtld_hidden_data_def (__nptl_set_robust_list_avail) @@ -92,7 +95,13 @@ __tls_init_tp (void) } } - rseq_register_current_thread (pd); + { + bool do_rseq = true; +#if HAVE_TUNABLES + do_rseq = TUNABLE_GET (rseq, int, NULL); +#endif + rseq_register_current_thread (pd, do_rseq); + } /* Set initial thread's stack block from 0 up to __libc_stack_end. It will be bigger than it actually is, but for unwind.c/pt-longjmp.c diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list index ac5d053298..d24f4be0d0 100644 --- a/sysdeps/nptl/dl-tunables.list +++ b/sysdeps/nptl/dl-tunables.list @@ -27,5 +27,11 @@ glibc { type: SIZE_T default: 41943040 } + rseq { + type: INT_32 + minval: 0 + maxval: 1 + default: 1 + } } } diff --git a/sysdeps/nptl/internaltypes.h b/sysdeps/nptl/internaltypes.h index 6032a6b785..dec8c5b5ff 100644 --- a/sysdeps/nptl/internaltypes.h +++ b/sysdeps/nptl/internaltypes.h @@ -48,6 +48,7 @@ struct pthread_attr #define ATTR_FLAG_OLDATTR 0x0010 #define ATTR_FLAG_SCHED_SET 0x0020 #define ATTR_FLAG_POLICY_SET 0x0040 +#define ATTR_FLAG_DO_RSEQ 0x0080 /* Used to allocate a pthread_attr_t object which is also accessed internally. */ diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index eb0f5fc021..62a796f214 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -136,6 +136,12 @@ tests-internal += \ tst-sigcontext-get_pc \ # tests-internal +ifneq (no,$(have-tunables)) +tests-internal += \ + tst-rseq-disable \ + # tests-internal $(have-tunables) +endif + tests-time64 += \ tst-adjtimex-time64 \ tst-clock_adjtime-time64 \ @@ -227,6 +233,8 @@ $(objpfx)tst-mman-consts.out: ../sysdeps/unix/sysv/linux/tst-mman-consts.py < /dev/null > $@ 2>&1; $(evaluate-test) $(objpfx)tst-mman-consts.out: $(sysdeps-linux-python-deps) +tst-rseq-disable-ENV = GLIBC_TUNABLES=glibc.pthread.rseq=0 + endif # $(subdir) == misc ifeq ($(subdir),time) diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h index 909f547825..15bc7ffd6e 100644 --- a/sysdeps/unix/sysv/linux/rseq-internal.h +++ b/sysdeps/unix/sysv/linux/rseq-internal.h @@ -21,22 +21,27 @@ #include <sysdep.h> #include <errno.h> #include <kernel-features.h> +#include <stdbool.h> #include <stdio.h> #include <sys/rseq.h> #ifdef RSEQ_SIG static inline void -rseq_register_current_thread (struct pthread *self) +rseq_register_current_thread (struct pthread *self, bool do_rseq) { - int ret = INTERNAL_SYSCALL_CALL (rseq, - &self->rseq_area, sizeof (self->rseq_area), - 0, RSEQ_SIG); - if (INTERNAL_SYSCALL_ERROR_P (ret)) - THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + if (do_rseq) + { + int ret = INTERNAL_SYSCALL_CALL (rseq, &self->rseq_area, + sizeof (self->rseq_area), + 0, RSEQ_SIG); + if (!INTERNAL_SYSCALL_ERROR_P (ret)) + return; + } + THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); } #else /* RSEQ_SIG */ static inline void -rseq_register_current_thread (struct pthread *self) +rseq_register_current_thread (struct pthread *self, bool do_rseq) { THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); } diff --git a/sysdeps/unix/sysv/linux/tst-rseq-disable.c b/sysdeps/unix/sysv/linux/tst-rseq-disable.c new file mode 100644 index 0000000000..000e351872 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-rseq-disable.c @@ -0,0 +1,89 @@ +/* Test disabling of rseq registration via tunable. + Copyright (C) 2021 Free Software Foundation, Inc. + + 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 + <https://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <stdio.h> +#include <support/check.h> +#include <support/namespace.h> +#include <support/xthread.h> +#include <sysdep.h> +#include <unistd.h> + +#ifdef RSEQ_SIG + +/* Check that rseq can be registered and has not been taken by glibc. */ +static void +check_rseq_disabled (void) +{ + struct pthread *pd = THREAD_SELF; + TEST_COMPARE ((int) pd->rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + + int ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area), + 0, RSEQ_SIG); + if (ret == 0) + { + ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area), + RSEQ_FLAG_UNREGISTER, RSEQ_SIG); + TEST_COMPARE (ret, 0); + pd->rseq_area.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED; + } + else + { + TEST_VERIFY (errno != -EINVAL); + TEST_VERIFY (errno != -EBUSY); + } +} + +static void * +thread_func (void *ignored) +{ + check_rseq_disabled (); + return NULL; +} + +static void +proc_func (void *ignored) +{ + check_rseq_disabled (); +} + +static int +do_test (void) +{ + puts ("info: checking main thread"); + check_rseq_disabled (); + + puts ("info: checking main thread (2)"); + check_rseq_disabled (); + + puts ("info: checking new thread"); + xpthread_join (xpthread_create (NULL, thread_func, NULL)); + + puts ("info: checking subprocess"); + support_isolate_in_subprocess (proc_func, NULL); + + return 0; +} +#else /* !RSEQ_SIG */ +static int +do_test (void) +{ + FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test"); +} +#endif + +#include <support/test-driver.c> |