| Message ID | 2017429.gqNitNVd0C@mobilepool36.emlix.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fs/exec.c: simplify initial stack size expansion | expand |
On Wed, 19 Oct 2022 09:32:35 +0200, Rolf Eike Beer wrote: > I had a hard time trying to understand completely why it is using vm_end in > one side of the expression and vm_start in the other one, and using > something in the "if" clause that is not an exact copy of what is used > below. The whole point is that the stack_size variable that was used in the > "if" clause is the difference between vm_start and vm_end, which is not far > away but makes this thing harder to read than it must be. > > [...] Applied to for-next/execve, thanks! [1/1] fs/exec.c: simplify initial stack size expansion https://git.kernel.org/kees/c/bfb4a2b95875
diff --git a/fs/exec.c b/fs/exec.c index 768843477a49..990891c5d8fe 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -840,16 +840,13 @@ int setup_arg_pages(struct linux_binprm *bprm, * will align it up. */ rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK; + + stack_expand = min(rlim_stack, stack_size + stack_expand); + #ifdef CONFIG_STACK_GROWSUP - if (stack_size + stack_expand > rlim_stack) - stack_base = vma->vm_start + rlim_stack; - else - stack_base = vma->vm_end + stack_expand; + stack_base = vma->vm_start + stack_expand; #else - if (stack_size + stack_expand > rlim_stack) - stack_base = vma->vm_end - rlim_stack; - else - stack_base = vma->vm_start - stack_expand; + stack_base = vma->vm_end - stack_expand; #endif current->mm->start_stack = bprm->p; ret = expand_stack(vma, stack_base);
I had a hard time trying to understand completely why it is using vm_end in one side of the expression and vm_start in the other one, and using something in the "if" clause that is not an exact copy of what is used below. The whole point is that the stack_size variable that was used in the "if" clause is the difference between vm_start and vm_end, which is not far away but makes this thing harder to read than it must be. Signed-off-by: Rolf Eike Beer <eb@emlix.com> --- fs/exec.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)