Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread H.J. Lu
On Wed, Oct 7, 2020 at 8:46 AM Dave Martin wrote: > > On Wed, Oct 07, 2020 at 06:30:03AM -0700, H.J. Lu wrote: > > On Wed, Oct 7, 2020 at 3:47 AM Dave Martin wrote: > > > > > > On Tue, Oct 06, 2020 at 10:44:14AM -0700, H.J. Lu wrote: > > [...] > > > > > I updated my glibc patch to add both _SC_MI

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread Dave Martin
On Wed, Oct 07, 2020 at 06:30:03AM -0700, H.J. Lu wrote: > On Wed, Oct 7, 2020 at 3:47 AM Dave Martin wrote: > > > > On Tue, Oct 06, 2020 at 10:44:14AM -0700, H.J. Lu wrote: [...] > > > I updated my glibc patch to add both _SC_MINSIGSTKSZ and _SC_SIGSTKSZ. > > > _SC_MINSIGSTKSZ is the minimum s

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread H.J. Lu
On Wed, Oct 7, 2020 at 3:47 AM Dave Martin wrote: > > On Tue, Oct 06, 2020 at 10:44:14AM -0700, H.J. Lu wrote: > > On Tue, Oct 6, 2020 at 9:55 AM Dave Martin wrote: > > > > > > On Tue, Oct 06, 2020 at 08:34:06AM -0700, H.J. Lu wrote: > > > > On Tue, Oct 6, 2020 at 8:25 AM Dave Martin wrote: > >

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread Dave Martin
On Tue, Oct 06, 2020 at 10:44:14AM -0700, H.J. Lu wrote: > On Tue, Oct 6, 2020 at 9:55 AM Dave Martin wrote: > > > > On Tue, Oct 06, 2020 at 08:34:06AM -0700, H.J. Lu wrote: > > > On Tue, Oct 6, 2020 at 8:25 AM Dave Martin wrote: > > > > > > > > On Tue, Oct 06, 2020 at 05:12:29AM -0700, H.J. Lu w

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread Dave Martin
On Tue, Oct 06, 2020 at 11:30:42AM -0700, Dave Hansen wrote: > On 10/6/20 10:00 AM, Dave Martin wrote: > > On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: > >> On 10/6/20 8:25 AM, Dave Martin wrote: > >>> Or are people reporting real stack overruns on x86 today? > >> We have real overr

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-07 Thread Dave Martin
On Tue, Oct 06, 2020 at 08:21:00PM +0200, Florian Weimer wrote: > * Dave Martin via Libc-alpha: > > > On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: > >> On 10/6/20 8:25 AM, Dave Martin wrote: > >> > Or are people reporting real stack overruns on x86 today? > >> > >> We have real ov

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Hansen
On 10/6/20 10:00 AM, Dave Martin wrote: > On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: >> On 10/6/20 8:25 AM, Dave Martin wrote: >>> Or are people reporting real stack overruns on x86 today? >> We have real overruns. We have ~2800 bytes of XSAVE (regisiter) state >> mostly from AVX

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Florian Weimer
* Dave Martin via Libc-alpha: > On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: >> On 10/6/20 8:25 AM, Dave Martin wrote: >> > Or are people reporting real stack overruns on x86 today? >> >> We have real overruns. We have ~2800 bytes of XSAVE (regisiter) state >> mostly from AVX-512

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread H.J. Lu
On Tue, Oct 6, 2020 at 9:55 AM Dave Martin wrote: > > On Tue, Oct 06, 2020 at 08:34:06AM -0700, H.J. Lu wrote: > > On Tue, Oct 6, 2020 at 8:25 AM Dave Martin wrote: > > > > > > On Tue, Oct 06, 2020 at 05:12:29AM -0700, H.J. Lu wrote: > > > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > >

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Martin
On Tue, Oct 06, 2020 at 08:33:47AM -0700, Dave Hansen wrote: > On 10/6/20 8:25 AM, Dave Martin wrote: > > Or are people reporting real stack overruns on x86 today? > > We have real overruns. We have ~2800 bytes of XSAVE (regisiter) state > mostly from AVX-512, and a 2048 byte MINSIGSTKSZ. Right.

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Martin
On Tue, Oct 06, 2020 at 08:34:06AM -0700, H.J. Lu wrote: > On Tue, Oct 6, 2020 at 8:25 AM Dave Martin wrote: > > > > On Tue, Oct 06, 2020 at 05:12:29AM -0700, H.J. Lu wrote: > > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu w

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread H.J. Lu
On Tue, Oct 6, 2020 at 8:43 AM Dave Martin wrote: > > On Tue, Oct 06, 2020 at 08:18:03AM -0700, H.J. Lu wrote: > > On Tue, Oct 6, 2020 at 5:12 AM H.J. Lu wrote: > > > > > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote:

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Hansen
On 10/6/20 8:25 AM, Dave Martin wrote: > Or are people reporting real stack overruns on x86 today? We have real overruns. We have ~2800 bytes of XSAVE (regisiter) state mostly from AVX-512, and a 2048 byte MINSIGSTKSZ.

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Martin
On Tue, Oct 06, 2020 at 08:18:03AM -0700, H.J. Lu wrote: > On Tue, Oct 6, 2020 at 5:12 AM H.J. Lu wrote: > > > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > > > > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > >

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread H.J. Lu
On Tue, Oct 6, 2020 at 8:25 AM Dave Martin wrote: > > On Tue, Oct 06, 2020 at 05:12:29AM -0700, H.J. Lu wrote: > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > > > > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > >

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Martin
On Tue, Oct 06, 2020 at 05:12:29AM -0700, H.J. Lu wrote: > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > > > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > > > > > > > On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S.

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread H.J. Lu
On Tue, Oct 6, 2020 at 5:12 AM H.J. Lu wrote: > > On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > > > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > > > > > > > On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S. Bae wrot

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread H.J. Lu
On Tue, Oct 6, 2020 at 2:25 AM Dave Martin wrote: > > On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > > > > > On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S. Bae wrote: > > > > During signal entry, the kernel pushes data onto t

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-06 Thread Dave Martin
On Mon, Oct 05, 2020 at 10:17:06PM +0100, H.J. Lu wrote: > On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > > > On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S. Bae wrote: > > > During signal entry, the kernel pushes data onto the normal userspace > > > stack. On x86, the data pushed onto t

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-05 Thread H.J. Lu
On Mon, Oct 5, 2020 at 6:45 AM Dave Martin wrote: > > On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S. Bae wrote: > > During signal entry, the kernel pushes data onto the normal userspace > > stack. On x86, the data pushed onto the user stack includes XSAVE state, > > which has grown over time a

Re: [RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-10-05 Thread Dave Martin
On Tue, Sep 29, 2020 at 01:57:42PM -0700, Chang S. Bae wrote: > During signal entry, the kernel pushes data onto the normal userspace > stack. On x86, the data pushed onto the user stack includes XSAVE state, > which has grown over time as new features and larger registers have been > added to the

[RFC PATCH 0/4] x86: Improve Minimum Alternate Stack Size

2020-09-29 Thread Chang S. Bae
During signal entry, the kernel pushes data onto the normal userspace stack. On x86, the data pushed onto the user stack includes XSAVE state, which has grown over time as new features and larger registers have been added to the architecture. MINSIGSTKSZ is a constant provided in the kernel signal