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Date: Mon, 29 Feb 2016 16:57:13 +0100
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH 15/18] uprobes: wait for mmap_sem for write killable
Message-ID: <20160229155712.GA1964@redhat.com>
References: <1456752417-9626-1-git-send-email-mhocko@kernel.org>
 <1456752417-9626-16-git-send-email-mhocko@kernel.org>
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To: Michal Hocko <mhocko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, Alex Deucher <alexander.deucher@amd.com>, Alex Thorlton <athorlton@sgi.com>, Andrea Arcangeli <aarcange@redhat.com>, Andy Lutomirski <luto@amacapital.net>, Benjamin LaHaise <bcrl@kvack.org>, Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>, Daniel Vetter <daniel.vetter@intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, David Airlie <airlied@linux.ie>, Davidlohr Bueso <dave@stgolabs.net>, David Rientjes <rientjes@google.com>, "H . Peter Anvin" <hpa@zytor.com>, Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, Konstantin Khlebnikov <koct9i@gmail.com>, linux-arch@vger.kernel.org, Mel Gorman <mgorman@suse.de>, Peter Zijlstra <peterz@infradead.org>, Petr Cermak <petrcermak@chromium.org>, Thomas Gleixner <tglx@linutronix.de>, Michal Hocko <mhocko@suse.com>
Message-ID: <20160229155713.Vv1mVVnWnQpDLqFyDkM5sEdykmB7GQ4ifTWRfsv-SB4@z>

On 02/29, Michal Hocko wrote:
>
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1130,7 +1130,9 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
>  	struct vm_area_struct *vma;
>  	int ret;
>
> -	down_write(&mm->mmap_sem);
> +	if (down_write_killable(&mm->mmap_sem))
> +		return -EINTR;
> +

Yes, but then dup_xol_work() should probably check fatal_signal_pending() to
suppress uprobe_warn(), the warning looks like a kernel problem.

Oleg.