Re: Blocking MVar# primops not performing stack checks?

[Andreas Klebinger]

I just took a look at the implementation and it looks like you are right
Cheng.

I opened a ticket here: https://gitlab.haskell.org/ghc/ghc/issues/17893


Carter Schonwald schrieb am 02.03.2020 um 06:27:

The simplest way to answer this is if you can help us construct a
program, whether as Haskell or cmm, which tickles the failure you
suspect is there ?

The rts definitely gets less love overall.  And there’s fewer folks
involved in those layers overall.



On Wed, Feb 26, 2020 at 10:03 AM Shao, Cheng mailto:cheng.s...@tweag.io>> wrote:

Hi all,

When an MVar# primop blocks, it jumps to a function in
HeapStackCheck.cmm which pushes a RET_SMALL stack frame before
returning to the scheduler (e.g. the takeMVar# primop jumps to
stg_block_takemvar for stack adjustment). But these functions directly
bump Sp without checking for possible stack overflow, I wonder if it
is a bug?

Cheers,
Cheng
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Re: Blocking MVar# primops not performing stack checks?

[Carter Schonwald]

The simplest way to answer this is if you can help us construct a program,
whether as Haskell or cmm, which tickles the failure you suspect is there ?

The rts definitely gets less love overall.  And there’s fewer folks
involved in those layers overall.



On Wed, Feb 26, 2020 at 10:03 AM Shao, Cheng  wrote:

> Hi all,
>
> When an MVar# primop blocks, it jumps to a function in
> HeapStackCheck.cmm which pushes a RET_SMALL stack frame before
> returning to the scheduler (e.g. the takeMVar# primop jumps to
> stg_block_takemvar for stack adjustment). But these functions directly
> bump Sp without checking for possible stack overflow, I wonder if it
> is a bug?
>
> Cheers,
> Cheng
> ___
> ghc-devs mailing list
> ghc-devs@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
>
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Blocking MVar# primops not performing stack checks?

[Shao, Cheng]

Hi all,

When an MVar# primop blocks, it jumps to a function in
HeapStackCheck.cmm which pushes a RET_SMALL stack frame before
returning to the scheduler (e.g. the takeMVar# primop jumps to
stg_block_takemvar for stack adjustment). But these functions directly
bump Sp without checking for possible stack overflow, I wonder if it
is a bug?

Cheers,
Cheng
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