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From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Anthony Yznaga <anthony.yznaga@oracle.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org
Cc: mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com,
	bp@alien8.de, x86@kernel.org, hpa@zytor.com,
	viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
	arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org,
	gerg@linux-m68k.org, christian.brauner@ubuntu.com,
	peterz@infradead.org, esyr@redhat.com, jgg@ziepe.ca,
	christian@kellner.me, areber@redhat.com, cyphar@cyphar.com,
	steven.sistare@oracle.com
Subject: Re: [RFC PATCH 5/5] mm: introduce MADV_DOEXEC
Date: Tue, 28 Jul 2020 16:22:40 +0300	[thread overview]
Message-ID: <743a51db-dc27-c49c-9c65-ac164f5283ba@virtuozzo.com> (raw)
In-Reply-To: <1595869887-23307-6-git-send-email-anthony.yznaga@oracle.com>

On 27.07.2020 20:11, Anthony Yznaga wrote:
> madvise MADV_DOEXEC preserves a memory range across exec.  Initially
> only supported for non-executable, non-stack, anonymous memory.
> MADV_DONTEXEC reverts the effect of a previous MADV_DOXEXEC call and
> undoes the preservation of the range.  After a successful exec call,
> the behavior of all ranges reverts to MADV_DONTEXEC.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
> ---
>  include/uapi/asm-generic/mman-common.h |  3 +++
>  mm/madvise.c                           | 25 +++++++++++++++++++++++++
>  2 files changed, 28 insertions(+)
> 
> diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
> index f94f65d429be..7c5f616b28f7 100644
> --- a/include/uapi/asm-generic/mman-common.h
> +++ b/include/uapi/asm-generic/mman-common.h
> @@ -72,6 +72,9 @@
>  #define MADV_COLD	20		/* deactivate these pages */
>  #define MADV_PAGEOUT	21		/* reclaim these pages */
>  
> +#define MADV_DOEXEC	22		/* do inherit across exec */
> +#define MADV_DONTEXEC	23		/* don't inherit across exec */
> +
>  /* compatibility flags */
>  #define MAP_FILE	0
>  
> diff --git a/mm/madvise.c b/mm/madvise.c
> index dd1d43cf026d..b447fa748649 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -103,6 +103,26 @@ static long madvise_behavior(struct vm_area_struct *vma,
>  	case MADV_KEEPONFORK:
>  		new_flags &= ~VM_WIPEONFORK;
>  		break;
> +	case MADV_DOEXEC:

For me MADV_KEEPONEXEC sounds better as it's symmetric to MADV_KEEPONFORK.

> +		/*
> +		 * MADV_DOEXEC is only supported on private, non-executable,
> +		 * non-stack anonymous memory and if the VM_EXEC_KEEP flag
> +		 * is available.
> +		 */
> +		if (!VM_EXEC_KEEP || vma->vm_file || vma->vm_flags & (VM_EXEC|VM_SHARED|VM_STACK)) {
> +			error = -EINVAL;
> +			goto out;
> +		}
> +		new_flags |= (new_flags & ~VM_MAYEXEC) | VM_EXEC_KEEP;
> +		break;
> +	case MADV_DONTEXEC:
> +		if (!VM_EXEC_KEEP) {
> +			error = -EINVAL;
> +			goto out;
> +		}
> +		if (new_flags & VM_EXEC_KEEP)
> +			new_flags |= (new_flags & ~VM_EXEC_KEEP) | VM_MAYEXEC;
> +		break;
>  	case MADV_DONTDUMP:
>  		new_flags |= VM_DONTDUMP;
>  		break;
> @@ -983,6 +1003,8 @@ static int madvise_inject_error(int behavior,
>  	case MADV_SOFT_OFFLINE:
>  	case MADV_HWPOISON:
>  #endif
> +	case MADV_DOEXEC:
> +	case MADV_DONTEXEC:
>  		return true;
>  
>  	default:
> @@ -1037,6 +1059,9 @@ static int madvise_inject_error(int behavior,
>   *  MADV_DONTDUMP - the application wants to prevent pages in the given range
>   *		from being included in its core dump.
>   *  MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
> + *  MADV_DOEXEC - On exec, preserve and duplicate this area in the new process
> + *		  if the new process allows it.
> + *  MADV_DONTEXEC - Undo the effect of MADV_DOEXEC.
>   *
>   * return values:
>   *  zero    - success
> 


  reply	other threads:[~2020-07-28 13:23 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 17:11 [RFC PATCH 0/5] madvise MADV_DOEXEC Anthony Yznaga
2020-07-27 17:07 ` Eric W. Biederman
2020-07-27 18:00   ` Steven Sistare
2020-07-28 13:40     ` Christian Brauner
2020-07-27 17:11 ` [RFC PATCH 1/5] elf: reintroduce using MAP_FIXED_NOREPLACE for elf executable mappings Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 2/5] mm: do not assume only the stack vma exists in setup_arg_pages() Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 3/5] mm: introduce VM_EXEC_KEEP Anthony Yznaga
2020-07-28 13:38   ` Eric W. Biederman
2020-07-28 17:44     ` Anthony Yznaga
2020-07-29 13:52   ` Kirill A. Shutemov
2020-07-29 23:20     ` Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 4/5] exec, elf: require opt-in for accepting preserved mem Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 5/5] mm: introduce MADV_DOEXEC Anthony Yznaga
2020-07-28 13:22   ` Kirill Tkhai [this message]
2020-07-28 14:06     ` Steven Sistare
2020-07-28 11:34 ` [RFC PATCH 0/5] madvise MADV_DOEXEC Kirill Tkhai
2020-07-28 17:28   ` Anthony Yznaga
2020-07-28 14:23 ` Andy Lutomirski
2020-07-28 14:30   ` Steven Sistare
2020-07-30 15:22 ` Matthew Wilcox
2020-07-30 15:27   ` Christian Brauner
2020-07-30 15:34     ` Matthew Wilcox
2020-07-30 15:54       ` Christian Brauner
2020-07-31  9:12     ` Stefan Hajnoczi
2020-07-30 15:59   ` Steven Sistare
2020-07-30 17:12     ` Matthew Wilcox
2020-07-30 17:35       ` Steven Sistare
2020-07-30 17:49         ` Matthew Wilcox
2020-07-30 18:27           ` Steven Sistare
2020-07-30 21:58             ` Eric W. Biederman
2020-07-31 14:57               ` Steven Sistare
2020-07-31 15:27                 ` Matthew Wilcox
2020-07-31 16:11                   ` Steven Sistare
2020-07-31 16:56                     ` Jason Gunthorpe
2020-07-31 17:15                       ` Steven Sistare
2020-07-31 17:48                         ` Jason Gunthorpe
2020-07-31 17:55                           ` Steven Sistare
2020-08-03  8:32                             ` David Laight
2020-07-31 17:23                     ` Matthew Wilcox
2020-08-03 15:28                 ` Eric W. Biederman
2020-08-03 15:42                   ` James Bottomley
2020-08-03 20:03                     ` Steven Sistare
2020-08-04  8:44                     ` David Laight
2020-08-04 11:13                       ` Matthew Wilcox
2020-08-03 19:29                   ` Steven Sistare
2020-07-31 19:41 ` Steven Sistare
2021-07-08  9:52 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-07-08 12:48   ` Steven Sistare

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