Content-Type: multipart/mixed; boundary="===============5411445770015646830==" MIME-Version: 1.0 From: Huang Ying To: lkp@lists.01.org Subject: Re: [mm] cc87317726f: WARNING: CPU: 0 PID: 1 at drivers/iommu/io-pgtable-arm.c:413 __arm_lpae_unmap+0x341/0x380() Date: Wed, 18 Mar 2015 09:53:54 +0800 Message-ID: <1426643634.5570.14.camel@intel.com> In-Reply-To: <20150317192413.GA7772@phnom.home.cmpxchg.org> List-Id: --===============5411445770015646830== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Tue, 2015-03-17 at 15:24 -0400, Johannes Weiner wrote: > On Tue, Mar 17, 2015 at 10:15:29AM -0700, Linus Torvalds wrote: > > Explicitly adding the emails of other people involved with that commit > > and the original oom thread to make sure people are aware, since this > > didn't get any response. > > = > > Commit cc87317726f8 fixed some behavior, but also seems to have turned > > an oom situation into a complete hang. So presumably we shouldn't loop > > *forever*. Hmm? > = > It seems we are between a rock and a hard place here, as we reverted > specifically to that endless looping on request of filesystem people. > They said[1] they rely on these allocations never returning NULL, or > they might fail inside a transactions and corrupt on-disk data. > = > Huang, against which kernels did you first run this test on this exact > setup? Is there a chance you could try to run a kernel without/before > 9879de7373fc? I want to make sure I'm not missing something, but all > versions preceding this commit should also have the same hang. There > should only be a tiny window between 9879de7373fc and cc87317726f8 -- > v3.19 -- where these allocations are allowed to fail. I checked the test result of v3.19-rc6. It shows that boot will hang at the same position. BTW: the test is run on 32 bit system. Best Regards, Huang, Ying --===============5411445770015646830==--