Re: [PATCHv3 01/12] uprobes: split THPs before trying replace them

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From: Oleg Nesterov <oleg@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCHv3 01/12] uprobes: split THPs before trying replace them
Date: Tue, 31 Jan 2017 16:44:42 +0100	[thread overview]
Message-ID: <20170131154442.GA21637@redhat.com> (raw)
In-Reply-To: <20170129173858.45174-2-kirill.shutemov@linux.intel.com>

On 01/29, Kirill A. Shutemov wrote:
>
> For THPs page_check_address() always fails. It leads to endless loop in
> uprobe_write_opcode().
>
> Testcase with huge-tmpfs (not sure if it's possible to trigger this
> uprobe codepath for anon memory):

No, you can't probe the anonymous memory,

> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -300,8 +300,8 @@ int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr,
>  
>  retry:
>  	/* Read the page with vaddr into memory */
> -	ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
> -			&vma, NULL);
> +	ret = get_user_pages_remote(NULL, mm, vaddr, 1,
> +			FOLL_FORCE | FOLL_SPLIT, &old_page, &vma, NULL);
>  	if (ret <= 0)
>  		return ret;

Thanks,

Acked-by: Oleg Nesterov <oleg@redhat.com>

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WARNING: multiple messages have this Message-ID (diff)

From: Oleg Nesterov <oleg@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCHv3 01/12] uprobes: split THPs before trying replace them
Date: Tue, 31 Jan 2017 16:44:42 +0100	[thread overview]
Message-ID: <20170131154442.GA21637@redhat.com> (raw)
In-Reply-To: <20170129173858.45174-2-kirill.shutemov@linux.intel.com>

On 01/29, Kirill A. Shutemov wrote:
>
> For THPs page_check_address() always fails. It leads to endless loop in
> uprobe_write_opcode().
>
> Testcase with huge-tmpfs (not sure if it's possible to trigger this
> uprobe codepath for anon memory):

No, you can't probe the anonymous memory,

> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -300,8 +300,8 @@ int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr,
>  
>  retry:
>  	/* Read the page with vaddr into memory */
> -	ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
> -			&vma, NULL);
> +	ret = get_user_pages_remote(NULL, mm, vaddr, 1,
> +			FOLL_FORCE | FOLL_SPLIT, &old_page, &vma, NULL);
>  	if (ret <= 0)
>  		return ret;

Thanks,

Acked-by: Oleg Nesterov <oleg@redhat.com>

next prev parent reply	other threads:[~2017-01-31 15:44 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-29 17:38 [PATCHv3 00/12] Fix few rmap-related THP bugs Kirill A. Shutemov
2017-01-29 17:38 ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 01/12] uprobes: split THPs before trying replace them Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-31 15:44   ` Oleg Nesterov [this message]
2017-01-31 15:44     ` Oleg Nesterov
2017-01-29 17:38 ` [PATCHv3 02/12] mm: introduce page_vma_mapped_walk() Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 03/12] mm: fix handling PTE-mapped THPs in page_referenced() Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-02-02 15:26   ` Michal Hocko
2017-02-02 15:26     ` Michal Hocko
2017-02-04 10:33     ` Kirill A. Shutemov
2017-02-04 10:33       ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 04/12] mm: fix handling PTE-mapped THPs in page_idle_clear_pte_refs() Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 05/12] mm, rmap: check all VMAs that PTE-mapped THP can be part of Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 06/12] mm: convert page_mkclean_one() to use page_vma_mapped_walk() Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 07/12] mm: convert try_to_unmap_one() " Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 08/12] mm, ksm: convert write_protect_page() " Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 09/12] mm, uprobes: convert __replace_page() " Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 10/12] mm: convert page_mapped_in_vma() " Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 11/12] mm: drop page_check_address{,_transhuge} Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov
2017-01-29 17:38 ` [PATCHv3 12/12] mm: convert remove_migration_pte() to use page_vma_mapped_walk() Kirill A. Shutemov
2017-01-29 17:38   ` Kirill A. Shutemov

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