Re: KASAN & the vmalloc area

2016-11-09 Thread Dmitry Vyukov
On Wed, Nov 9, 2016 at 10:30 AM, Mark Rutland wrote: >> >> I've seen the same iteration slowness problem on x86 with >> >> CONFIG_DEBUG_RODATA which walks all pages. The is about 1 minute, but >> >> it is enough to trigger rcu stall warning. >> > >> > Interesting; do you know where that happens? I

Re: KASAN & the vmalloc area

2016-11-09 Thread Mark Rutland
On Wed, Nov 09, 2016 at 10:16:03AM -0800, Dmitry Vyukov wrote: > On Wed, Nov 9, 2016 at 2:56 AM, Mark Rutland wrote: > > On Tue, Nov 08, 2016 at 02:09:27PM -0800, Dmitry Vyukov wrote: > >> On Tue, Nov 8, 2016 at 11:03 AM, Mark Rutland wrote: > >> I've seen the same iteration slowness problem on x

Re: KASAN & the vmalloc area

2016-11-09 Thread Dmitry Vyukov
On Wed, Nov 9, 2016 at 8:53 AM, Andrey Ryabinin wrote: > On 11/08/2016 10:03 PM, Mark Rutland wrote: >> Hi, >> >> I see a while back [1] there was a discussion of what to do about KASAN >> and vmapped stacks, but it doesn't look like that was solved, judging by >> the vmapped stacks pull [2] for v

Re: KASAN & the vmalloc area

2016-11-09 Thread Dmitry Vyukov
On Wed, Nov 9, 2016 at 2:56 AM, Mark Rutland wrote: > On Tue, Nov 08, 2016 at 02:09:27PM -0800, Dmitry Vyukov wrote: >> On Tue, Nov 8, 2016 at 11:03 AM, Mark Rutland wrote: >> > When KASAN is selected, we allocate shadow for the whole vmalloc area, >> > using common zero pte, pmd, pud tables. Wal

Re: KASAN & the vmalloc area

2016-11-09 Thread Andrey Ryabinin
On 11/08/2016 10:03 PM, Mark Rutland wrote: > Hi, > > I see a while back [1] there was a discussion of what to do about KASAN > and vmapped stacks, but it doesn't look like that was solved, judging by > the vmapped stacks pull [2] for v4.9. > > I wondered whether anyone had looked at that since?

Re: KASAN & the vmalloc area

2016-11-09 Thread Mark Rutland
On Tue, Nov 08, 2016 at 02:09:27PM -0800, Dmitry Vyukov wrote: > On Tue, Nov 8, 2016 at 11:03 AM, Mark Rutland wrote: > > When KASAN is selected, we allocate shadow for the whole vmalloc area, > > using common zero pte, pmd, pud tables. Walking over these in the ptdump > > code takes a *very* long

Re: KASAN & the vmalloc area

2016-11-08 Thread Dmitry Vyukov
On Tue, Nov 8, 2016 at 11:03 AM, Mark Rutland wrote: > Hi, > > I see a while back [1] there was a discussion of what to do about KASAN > and vmapped stacks, but it doesn't look like that was solved, judging by > the vmapped stacks pull [2] for v4.9. > > I wondered whether anyone had looked at that

KASAN & the vmalloc area

2016-11-08 Thread Mark Rutland
Hi, I see a while back [1] there was a discussion of what to do about KASAN and vmapped stacks, but it doesn't look like that was solved, judging by the vmapped stacks pull [2] for v4.9. I wondered whether anyone had looked at that since? I have an additional reason to want to dynamically alloca