diff options
Diffstat (limited to 'usr/src/uts/common/os/grow.c')
| -rw-r--r-- | usr/src/uts/common/os/grow.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/usr/src/uts/common/os/grow.c b/usr/src/uts/common/os/grow.c index 647bca2542..de2a4f26c4 100644 --- a/usr/src/uts/common/os/grow.c +++ b/usr/src/uts/common/os/grow.c @@ -19,7 +19,10 @@ * CDDL HEADER END */ -/* Copyright 2013 OmniTI Computer Consulting, Inc. All rights reserved. */ +/* + * Copyright 2013 OmniTI Computer Consulting, Inc. All rights reserved. + * Copyright 2017 Joyent, Inc. + */ /* * Copyright 2009 Sun Microsystems, Inc. All rights reserved. @@ -329,9 +332,10 @@ grow(caddr_t sp) } else { err = grow_internal(sp, p->p_stkpageszc); } + newsize = p->p_stksize; as_rangeunlock(as); - if (err == 0 && (newsize = p->p_stksize) > oldsize) { + if (err == 0 && newsize > oldsize) { ASSERT(IS_P2ALIGNED(oldsize, PAGESIZE)); ASSERT(IS_P2ALIGNED(newsize, PAGESIZE)); /* @@ -424,6 +428,7 @@ grow_internal(caddr_t sp, uint_t growszc) struct proc *p = curproc; size_t newsize; size_t oldsize; + uintptr_t new_start; int error; size_t pgsz; uint_t szc; @@ -494,7 +499,32 @@ grow_internal(caddr_t sp, uint_t growszc) } crargs.lgrp_mem_policy_flags = LGRP_MP_FLAG_EXTEND_DOWN; - if ((error = as_map(p->p_as, p->p_usrstack - newsize, newsize - oldsize, + /* + * The stack is about to grow into its guard. This can be acceptable + * if the size restriction on the stack has been expanded since its + * initialization during exec(). In such cases, the guard segment will + * be shrunk, provided the new size is reasonable. + */ + new_start = (uintptr_t)p->p_usrstack - newsize; + if (p->p_stkg_start != 0 && new_start > p->p_stkg_start && + new_start < p->p_stkg_end) { + const size_t unmap_sz = p->p_stkg_end - new_start; + const size_t remain_sz = new_start - p->p_stkg_start; + extern size_t stack_guard_min_sz; + + /* Do not allow the guard to shrink below minimum size */ + if (remain_sz < stack_guard_min_sz) { + return (ENOMEM); + } + + error = as_unmap(p->p_as, (caddr_t)new_start, unmap_sz); + if (error != 0) { + return (error); + } + p->p_stkg_end -= unmap_sz; + } + + if ((error = as_map(p->p_as, (caddr_t)new_start, newsize - oldsize, segvn_create, &crargs)) != 0) { if (error == EAGAIN) { cmn_err(CE_WARN, "Sorry, no swap space to grow stack " |