From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
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Subject: Re: [PATCH v5 2/2] mm: add a field to store names for private anonymous memory
Date: Fri, 21 Aug 2020 00:40:03 +0300 [thread overview]
Message-ID: <20200820214003.GR2074@grain> (raw)
In-Reply-To: <20200819141650.7462-3-sumit.semwal@linaro.org>
On Wed, Aug 19, 2020 at 07:46:50PM +0530, Sumit Semwal wrote:
...
> Userspace can set the name for a region of memory by calling
> prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name);
> Setting the name to NULL clears it.
>
> The name is stored in a user pointer in the shared union in vm_area_struct
> that points to a null terminated string inside the user process. vmas
> that point to the same address and are otherwise mergeable will be merged,
> but vmas that point to equivalent strings at different addresses will not
> be merged.
...
Guys, could you please enlighen me, I don't understand -- we pass some
random user-space pointer and save it in vm_area_struct then in procfs
we treat it as "string" and print out? What prevents me to put some crap
here then unmap this pointer the kernel will cause page fault in procfs
output (in best scenario)?
next prev parent reply other threads:[~2020-08-20 21:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 14:16 [PATCH v5 0/2] Anonymous VMA naming patches Sumit Semwal
2020-08-19 14:16 ` [PATCH v5 1/2] mm: rearrange madvise code to allow for reuse Sumit Semwal
2020-08-19 14:16 ` [PATCH v5 2/2] mm: add a field to store names for private anonymous memory Sumit Semwal
2020-08-19 14:37 ` Michal Hocko
2020-08-19 15:02 ` Matthew Wilcox
2020-08-19 17:48 ` Sumit Semwal
2020-08-20 15:46 ` Oleg Nesterov
2020-08-19 17:14 ` kernel test robot
2020-08-19 17:42 ` kernel test robot
2020-08-20 7:58 ` Michal Hocko
2020-08-20 23:28 ` Colin Cross
2020-08-21 3:21 ` Sumit Semwal
2020-08-21 7:24 ` Michal Hocko
2020-08-21 7:53 ` Michal Hocko
2020-08-21 8:02 ` Sumit Semwal
2020-08-20 16:00 ` Oleg Nesterov
2020-08-20 21:15 ` Kees Cook
2020-08-21 3:15 ` Sumit Semwal
2020-08-21 3:14 ` Sumit Semwal
2020-08-20 21:40 ` Cyrill Gorcunov [this message]
2020-08-20 21:45 ` Colin Cross
2020-08-20 22:15 ` Cyrill Gorcunov
2020-08-20 23:51 ` Colin Cross
2020-08-21 7:05 ` Cyrill Gorcunov
2020-08-20 21:45 ` Dave Hansen
2020-08-20 21:59 ` Cyrill Gorcunov
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