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Fri, 9 Sep 2022 13:43:29 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A7FDE42047; Fri, 9 Sep 2022 13:43:29 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9374A4203F; Fri, 9 Sep 2022 13:43:28 +0000 (GMT) Received: from [9.145.83.17] (unknown [9.145.83.17]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 9 Sep 2022 13:43:28 +0000 (GMT) Message-ID: <83a36761-2045-3f46-3088-a751c5263b81@linux.ibm.com> Date: Fri, 9 Sep 2022 15:43:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [RFC PATCH RESEND 15/28] mm/mmap: mark adjacent VMAs as locked if they can grow into unmapped area Content-Language: fr To: Suren Baghdasaryan , akpm@linux-foundation.org References: <20220901173516.702122-1-surenb@google.com> <20220901173516.702122-16-surenb@google.com> From: Laurent Dufour In-Reply-To: <20220901173516.702122-16-surenb@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: vsmxLApnSa4kFm4DsE4c9nzLp7_dueVe X-Proofpoint-ORIG-GUID: _47dY4KcG9Nanbo62JUX-I9vUetE4UJD X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-09_08,2022-09-09_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 priorityscore=1501 mlxscore=0 bulkscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 malwarescore=0 mlxlogscore=894 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2209090047 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: michel@lespinasse.org, joelaf@google.com, songliubraving@fb.com, mhocko@suse.com, david@redhat.com, peterz@infradead.org, bigeasy@linutronix.de, peterx@redhat.com, dhowells@redhat.com, linux-mm@kvack.org, jglisse@google.com, dave@stgolabs.net, minchan@google.com, x86@kernel.org, hughd@google.com, willy@infradead.org, laurent.dufour@fr.ibm.com, mgorman@suse.de, rientjes@google.com, axelrasmussen@google.com, kernel-team@android.com, paulmck@kernel.org, liam.howlett@oracle.com, luto@kernel.org, vbabka@suse.cz, linux-arm-kernel@lists.infradead.org, kent.overstreet@linux.dev, linux-kernel@vger.kernel.org, hannes@cmpxchg.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 01/09/2022 à 19:35, Suren Baghdasaryan a écrit : > While unmapping VMAs, adjacent VMAs might be able to grow into the area > being unmapped. In such cases mark adjacent VMAs as locked to prevent > this growth. > > Signed-off-by: Suren Baghdasaryan > --- > mm/mmap.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index b0d78bdc0de0..b31cc97c2803 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2680,10 +2680,14 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, > * VM_GROWSUP VMA. Such VMAs can change their size under > * down_read(mmap_lock) and collide with the VMA we are about to unmap. > */ > - if (vma && (vma->vm_flags & VM_GROWSDOWN)) > + if (vma && (vma->vm_flags & VM_GROWSDOWN)) { > + vma_mark_locked(vma); > return false; > - if (prev && (prev->vm_flags & VM_GROWSUP)) > + } > + if (prev && (prev->vm_flags & VM_GROWSUP)) { > + vma_mark_locked(prev); > return false; > + } > return true; > } > That looks right to be. But, in addition to that, like the previous patch, all the VMAs to be detached from the tree in the loop above, should be marked locked just before calling vm_rb_erase().