diff options
| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2017-12-06 13:05:50 +0000 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2018-01-08 19:02:11 +0000 |
| commit | 630f4cc3aa019ede55976ea561f1a7af2f068639 (patch) | |
| tree | 67f9cc70df8a9b90122106ec5be5ac7495f00dda /nptl | |
| parent | c70e4e9c9efff9df4c847dd7cfd81bae674219ab (diff) | |
[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.c | 4 | ||||
| -rw-r--r-- | nptl/descr.h | 4 | ||||
| -rw-r--r-- | nptl/nptl-init.c | 5 | ||||
| -rw-r--r-- | nptl/pthread_getattr_np.c | 7 |
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 |