The documentation for ignore_rlimit_data says that it will print a warning
at first misuse. Yet it doesn't seem to do that. Fix the code to print
the warning even when we allow the process to continue.
Signed-off-by: David Woodhouse <[email protected]>
---
We should probably also do what Linus suggested in
https://lkml.org/lkml/2016/9/16/585
mm/mmap.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 9efdc021..dd76ea3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3184,13 +3184,15 @@ bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
if (rlimit(RLIMIT_DATA) == 0 &&
mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
return true;
- if (!ignore_rlimit_data) {
- pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits or use boot option ignore_rlimit_data.\n",
- current->comm, current->pid,
- (mm->data_vm + npages) << PAGE_SHIFT,
- rlimit(RLIMIT_DATA));
+
+ pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
+ current->comm, current->pid,
+ (mm->data_vm + npages) << PAGE_SHIFT,
+ rlimit(RLIMIT_DATA),
+ ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
+
+ if (!ignore_rlimit_data)
return false;
- }
}
return true;
--
2.7.4
On Tue, Feb 06, 2018 at 04:45:05PM +0000, David Woodhouse wrote:
> The documentation for ignore_rlimit_data says that it will print a warning
> at first misuse. Yet it doesn't seem to do that. Fix the code to print
> the warning even when we allow the process to continue.
>
> Signed-off-by: David Woodhouse <[email protected]>
> ---
> We should probably also do what Linus suggested in
> https://lkml.org/lkml/2016/9/16/585
>
Might be typo in docs I guess, Kostya?
On Tue, 2018-02-06 at 20:27 +0300, Cyrill Gorcunov wrote:
> On Tue, Feb 06, 2018 at 04:45:05PM +0000, David Woodhouse wrote:
> >
> > The documentation for ignore_rlimit_data says that it will print a warning
> > at first misuse. Yet it doesn't seem to do that. Fix the code to print
> > the warning even when we allow the process to continue.
> >
> > Signed-off-by: David Woodhouse <[email protected]>
> > ---
> > We should probably also do what Linus suggested in
> > https://lkml.org/lkml/2016/9/16/585
> >
> Might be typo in docs I guess, Kostya?
I prefer the documented behaviour to the actual behaviour :)
On Tue, Feb 6, 2018 at 7:45 PM, David Woodhouse <[email protected]> wrote:
> The documentation for ignore_rlimit_data says that it will print a warning
> at first misuse. Yet it doesn't seem to do that. Fix the code to print
> the warning even when we allow the process to continue.
Ack. But I think this was a misprint in docs.
Anyway, this knob is a kludge so we might warn once even if it is set.
So, somebody still have problems with this change?
I remember concerns about that "warn_once" isn't enough to detect
what's going wrong.
And probably we should invent "warn_sometimes".
>
> Signed-off-by: David Woodhouse <[email protected]>
> ---
> We should probably also do what Linus suggested in
> https://lkml.org/lkml/2016/9/16/585
>
> mm/mmap.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 9efdc021..dd76ea3 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3184,13 +3184,15 @@ bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
> if (rlimit(RLIMIT_DATA) == 0 &&
> mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
> return true;
> - if (!ignore_rlimit_data) {
> - pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits or use boot option ignore_rlimit_data.\n",
> - current->comm, current->pid,
> - (mm->data_vm + npages) << PAGE_SHIFT,
> - rlimit(RLIMIT_DATA));
> +
> + pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
> + current->comm, current->pid,
> + (mm->data_vm + npages) << PAGE_SHIFT,
> + rlimit(RLIMIT_DATA),
> + ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
> +
> + if (!ignore_rlimit_data)
> return false;
> - }
> }
>
> return true;
> --
> 2.7.4
>
On Tue, 2018-02-06 at 20:48 +0300, Konstantin Khlebnikov wrote:
> On Tue, Feb 6, 2018 at 7:45 PM, David Woodhouse <[email protected]> wrote:
> >
> > The documentation for ignore_rlimit_data says that it will print a warning
> > at first misuse. Yet it doesn't seem to do that. Fix the code to print
> > the warning even when we allow the process to continue.
>
> Ack. But I think this was a misprint in docs.
> Anyway, this knob is a kludge so we might warn once even if it is set.
Right. I think we definitely should. Otherwise, once set, there's no
real path to ever being able to *unset* it. Nothing well ever get
fixed.
> So, somebody still have problems with this change?
> I remember concerns about that "warn_once" isn't enough to detect
> what's going wrong.
> And probably we should invent "warn_sometimes".
That was covered by "should probably also do what Linus suggested…":
> > ---
> > We should probably also do what Linus suggested in
> > https://lkml.org/lkml/2016/9/16/585