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[37.188.133.21]) by smtp.gmail.com with ESMTPSA id r5sm4028253wrt.43.2020.02.20.02.41.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 02:41:20 -0800 (PST) Date: Thu, 20 Feb 2020 11:41:19 +0100 From: Michal Hocko To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, richardw.yang@linux.intel.com, david@redhat.com, osalvador@suse.de, dan.j.williams@intel.com Subject: Re: [PATCH v2 RESEND] mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM Message-ID: <20200220104119.GH20509@dhcp22.suse.cz> References: <20200219030454.4844-1-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219030454.4844-1-bhe@redhat.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 19-02-20 11:04:54, Baoquan He wrote: > From: Wei Yang > > When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page() > doesn't work before sparse_init_one_section() is called. This leads to a > crash when hotplug memory: > > [ 41.839170] BUG: unable to handle page fault for address: 0000000006400000 > [ 41.840663] #PF: supervisor write access in kernel mode > [ 41.841822] #PF: error_code(0x0002) - not-present page > [ 41.842970] PGD 0 P4D 0 > [ 41.843538] Oops: 0002 [#1] SMP PTI > [ 41.844125] CPU: 3 PID: 221 Comm: kworker/u16:1 Tainted: G W 5.5.0-next-20200205+ #343 > [ 41.845659] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 > [ 41.846977] Workqueue: kacpi_hotplug acpi_hotplug_work_fn > [ 41.847904] RIP: 0010:__memset+0x24/0x30 > [ 41.848660] Code: cc cc cc cc cc cc 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 > [ 41.851836] RSP: 0018:ffffb43ac0373c80 EFLAGS: 00010a87 > [ 41.852686] RAX: ffffffffffffffff RBX: ffff8a1518800000 RCX: 0000000000050000 > [ 41.853824] RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000006400000 > [ 41.854967] RBP: 0000000000140000 R08: 0000000000100000 R09: 0000000006400000 > [ 41.856107] R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000 > [ 41.857255] R13: 0000000000000028 R14: 0000000000000000 R15: ffff8a153ffd9280 > [ 41.858414] FS: 0000000000000000(0000) GS:ffff8a153ab00000(0000) knlGS:0000000000000000 > [ 41.859703] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 41.860627] CR2: 0000000006400000 CR3: 0000000136fca000 CR4: 00000000000006e0 > [ 41.861716] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 41.862680] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 41.863628] Call Trace: > [ 41.863983] sparse_add_section+0x1c9/0x26a > [ 41.864570] __add_pages+0xbf/0x150 > [ 41.865057] add_pages+0x12/0x60 > [ 41.865489] add_memory_resource+0xc8/0x210 > [ 41.866017] ? wake_up_q+0xa0/0xa0 > [ 41.866416] __add_memory+0x62/0xb0 > [ 41.866825] acpi_memory_device_add+0x13f/0x300 > [ 41.867410] acpi_bus_attach+0xf6/0x200 > [ 41.867890] acpi_bus_scan+0x43/0x90 > [ 41.868448] acpi_device_hotplug+0x275/0x3d0 > [ 41.868972] acpi_hotplug_work_fn+0x1a/0x30 > [ 41.869473] process_one_work+0x1a7/0x370 > [ 41.869953] worker_thread+0x30/0x380 > [ 41.870396] ? flush_rcu_work+0x30/0x30 > [ 41.870846] kthread+0x112/0x130 > [ 41.871236] ? kthread_create_on_node+0x60/0x60 > [ 41.871770] ret_from_fork+0x35/0x40 > > We should use memmap as it did. > > Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") > Signed-off-by: Wei Yang > Acked-by: David Hildenbrand > Reviewed-by: Baoquan He > CC: Dan Williams Acked-by: Michal Hocko > --- > v1->v2: > Add trace printed by triggered bug to log. > > v1 can be found here: > http://lkml.kernel.org/r/20200206125343.9070-1-richardw.yang@linux.intel.com > > mm/sparse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index c184b69460b7..596b2a45b100 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -876,7 +876,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, > * Poison uninitialized struct pages in order to catch invalid flags > * combinations. > */ > - page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages); > + page_init_poison(memmap, sizeof(struct page) * nr_pages); > > ms = __nr_to_section(section_nr); > set_section_nid(section_nr, nid); > -- > 2.17.2 > -- Michal Hocko SUSE Labs