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| author | John David Anglin <danglin@gcc.gnu.org> | 2017-07-15 12:40:13 -0400 |
|---|---|---|
| committer | John David Anglin <danglin@gcc.gnu.org> | 2017-07-15 12:40:13 -0400 |
| commit | 075385f98af239ff5807a5c6ed17fec51e048454 (patch) | |
| tree | 4daa5d6e521d62b372bc7e69bc9036d0b61b4b0f /nptl/allocatestack.c | |
| parent | 2759a2c1d8b950521ae76e62efe0114fd36b6e2d (diff) | |
| download | glibc-075385f98af239ff5807a5c6ed17fec51e048454.tar.gz glibc-075385f98af239ff5807a5c6ed17fec51e048454.tar.xz glibc-075385f98af239ff5807a5c6ed17fec51e048454.zip | |
Fix guard alignment in allocate_stack when stack grows up.
Diffstat (limited to 'nptl/allocatestack.c')
| -rw-r--r-- | nptl/allocatestack.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index ec7d42e027..ce2e24af95 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -697,8 +697,14 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, prot) != 0) goto mprot_error; #elif _STACK_GROWS_UP - if (__mprotect ((char *) pd - pd->guardsize, - pd->guardsize - guardsize, prot) != 0) + char *new_guard = (char *)(((uintptr_t) pd - guardsize) + & ~pagesize_m1); + char *old_guard = (char *)(((uintptr_t) pd - pd->guardsize) + & ~pagesize_m1); + /* The guard size difference might be > 0, but once rounded + to the nearest page the size difference might be zero. */ + if (new_guard > old_guard + && mprotect (old_guard, new_guard - old_guard, prot) != 0) goto mprot_error; #endif |