aboutsummaryrefslogtreecommitdiff
path: root/nptl
diff options
context:
space:
mode:
authorSzabolcs Nagy <szabolcs.nagy@arm.com>2017-12-06 13:05:50 +0000
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2018-01-08 19:02:11 +0000
commit630f4cc3aa019ede55976ea561f1a7af2f068639 (patch)
tree67f9cc70df8a9b90122106ec5be5ac7495f00dda /nptl
parentc70e4e9c9efff9df4c847dd7cfd81bae674219ab (diff)
downloadglibc-630f4cc3aa019ede55976ea561f1a7af2f068639.tar
glibc-630f4cc3aa019ede55976ea561f1a7af2f068639.tar.gz
glibc-630f4cc3aa019ede55976ea561f1a7af2f068639.tar.bz2
glibc-630f4cc3aa019ede55976ea561f1a7af2f068639.zip
[BZ #22637] Fix stack guard size accounting
Previously if user requested S stack and G guard when creating a thread, the total mapping was S and the actual available stack was S - G - static_tls, which is not what the user requested. This patch fixes the guard size accounting by pretending the user requested S+G stack. This way all later logic works out except when reporting the user requested stack size (pthread_getattr_np) or when computing the minimal stack size (__pthread_get_minstack). Normally this will increase thread stack allocations by one page. TLS accounting is not affected, that will require a separate fix. [BZ #22637] * nptl/descr.h (stackblock, stackblock_size): Update comments. * nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize. * nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from stacksize. * nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/allocatestack.c4
-rw-r--r--nptl/descr.h4
-rw-r--r--nptl/nptl-init.c5
-rw-r--r--nptl/pthread_getattr_np.c7
4 files changed, 12 insertions, 8 deletions
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 05b8ed331b..b374f4794d 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -532,6 +532,10 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
/* Make sure the size of the stack is enough for the guard and
eventually the thread descriptor. */
guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1;
+ if (guardsize < attr->guardsize || size + guardsize < guardsize)
+ /* Arithmetic overflow. */
+ return EINVAL;
+ size += guardsize;
if (__builtin_expect (size < ((guardsize + __static_tls_size
+ MINIMAL_REST_STACK + pagesize_m1)
& ~pagesize_m1),
diff --git a/nptl/descr.h b/nptl/descr.h
index da9c567a6f..1cc6b09d1e 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -383,9 +383,9 @@ struct pthread
/* Machine-specific unwind info. */
struct _Unwind_Exception exc;
- /* If nonzero pointer to area allocated for the stack and its
- size. */
+ /* If nonzero, pointer to the area allocated for the stack and guard. */
void *stackblock;
+ /* Size of the stackblock area including the guard. */
size_t stackblock_size;
/* Size of the included guard area. */
size_t guardsize;
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index c237a3675a..5a4b52419f 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -472,8 +472,5 @@ strong_alias (__pthread_initialize_minimal_internal,
size_t
__pthread_get_minstack (const pthread_attr_t *attr)
{
- struct pthread_attr *iattr = (struct pthread_attr *) attr;
-
- return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN
- + iattr->guardsize);
+ return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
}
diff --git a/nptl/pthread_getattr_np.c b/nptl/pthread_getattr_np.c
index 961d711fd2..ae12592294 100644
--- a/nptl/pthread_getattr_np.c
+++ b/nptl/pthread_getattr_np.c
@@ -57,9 +57,12 @@ pthread_getattr_np (pthread_t thread_id, pthread_attr_t *attr)
/* The sizes are subject to alignment. */
if (__glibc_likely (thread->stackblock != NULL))
{
- iattr->stacksize = thread->stackblock_size;
+ /* The stack size reported to the user should not include the
+ guard size. */
+ iattr->stacksize = thread->stackblock_size - thread->guardsize;
#if _STACK_GROWS_DOWN
- iattr->stackaddr = (char *) thread->stackblock + iattr->stacksize;
+ iattr->stackaddr = (char *) thread->stackblock
+ + thread->stackblock_size;
#else
iattr->stackaddr = (char *) thread->stackblock;
#endif