| Message ID | 20191019031939.9XlSnLGcS%akpm@linux-foundation.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/26] drivers/base/memory.c: don't access uninitialized memmaps in soft_offline_page_store() | expand |
Has this been properly reviewed? I do not see any Acks nor Reviewed-bys. On Fri 18-10-19 20:19:39, Andrew Morton wrote: > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> > Subject: mm/memunmap: don't access uninitialized memmap in memunmap_pages() > > Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6. > > This series fixes the access of uninitialized memmaps when shrinking > zones/nodes and when removing memory. Also, it contains all fixes for > crashes that can be triggered when removing certain namespace using > memunmap_pages() - ZONE_DEVICE, reported by Aneesh. > > We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be > more involved (we don't have SECTION_IS_ONLINE as an indicator), and > shrinking is only of limited use (set_zone_contiguous() cannot detect the > ZONE_DEVICE as contiguous). > > We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of > code to a minimum. Shrinking is especially necessary to keep > zone->contiguous set where possible, especially, on memory unplug of DIMMs > at zone boundaries. > > -------------------------------------------------------------------------- > > Zones are now properly shrunk when offlining memory blocks or when > onlining failed. This allows to properly shrink zones on memory unplug > even if the separate memory blocks of a DIMM were onlined to different > zones or re-onlined to a different zone after offlining. > > Example: > > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 0 > present 0 > managed 0 > :/# echo "online_movable" > /sys/devices/system/memory/memory41/state > :/# echo "online_movable" > /sys/devices/system/memory/memory43/state > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 98304 > present 65536 > managed 65536 > :/# echo 0 > /sys/devices/system/memory/memory43/online > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 32768 > present 32768 > managed 32768 > :/# echo 0 > /sys/devices/system/memory/memory41/online > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 0 > present 0 > managed 0 > > > This patch (of 10): > > With an altmap, the memmap falling into the reserved altmap space are not > initialized and, therefore, contain a garbage NID and a garbage zone. > Make sure to read the NID/zone from a memmap that was initialized. > > This fixes a kernel crash that is observed when destroying a namespace: > > [ 81.356173] kernel BUG at include/linux/mm.h:1107! > cpu 0x1: Vector: 700 (Program Check) at [c000000274087890] > pc: c0000000004b9728: memunmap_pages+0x238/0x340 > lr: c0000000004b9724: memunmap_pages+0x234/0x340 > ... > pid = 3669, comm = ndctl > kernel BUG at include/linux/mm.h:1107! > [c000000274087ba0] c0000000009e3500 devm_action_release+0x30/0x50 > [c000000274087bc0] c0000000009e4758 release_nodes+0x268/0x2d0 > [c000000274087c30] c0000000009dd144 device_release_driver_internal+0x174/0x240 > [c000000274087c70] c0000000009d9dfc unbind_store+0x13c/0x190 > [c000000274087cb0] c0000000009d8a24 drv_attr_store+0x44/0x60 > [c000000274087cd0] c0000000005a7470 sysfs_kf_write+0x70/0xa0 > [c000000274087d10] c0000000005a5cac kernfs_fop_write+0x1ac/0x290 > [c000000274087d60] c0000000004be45c __vfs_write+0x3c/0x70 > [c000000274087d80] c0000000004c26e4 vfs_write+0xe4/0x200 > [c000000274087dd0] c0000000004c2a6c ksys_write+0x7c/0x140 > [c000000274087e20] c00000000000bbd0 system_call+0x5c/0x68 > > The "page_zone(pfn_to_page(pfn)" was introduced by 69324b8f4833 ("mm, > devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support"), however, I > think we will never have driver reserved memory with > MEMORY_DEVICE_PRIVATE (no altmap AFAIKS). > > [david@redhat.com: minimze code changes, rephrase description] > Link: http://lkml.kernel.org/r/20191006085646.5768-2-david@redhat.com > Fixes: 2c2a5af6fed2 ("mm, memory_hotplug: add nid parameter to arch_remove_memory") > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Damian Tometzki <damian.tometzki@gmail.com> > Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> > Cc: Alexander Potapenko <glider@google.com> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Borislav Petkov <bp@alien8.de> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Christian Borntraeger <borntraeger@de.ibm.com> > Cc: Christophe Leroy <christophe.leroy@c-s.fr> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: Fenghua Yu <fenghua.yu@intel.com> > Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Halil Pasic <pasic@linux.ibm.com> > Cc: Heiko Carstens <heiko.carstens@de.ibm.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Jun Yao <yaojun8558363@gmail.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Masahiro Yamada <yamada.masahiro@socionext.com> > Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> > Cc: Mel Gorman <mgorman@techsingularity.net> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Mike Rapoport <rppt@linux.ibm.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: Pankaj Gupta <pagupta@redhat.com> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Pavel Tatashin <pasha.tatashin@soleen.com> > Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Qian Cai <cai@lca.pw> > Cc: Rich Felker <dalias@libc.org> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Steve Capper <steve.capper@arm.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Tom Lendacky <thomas.lendacky@amd.com> > Cc: Tony Luck <tony.luck@intel.com> > Cc: Vasily Gorbik <gor@linux.ibm.com> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Wei Yang <richard.weiyang@gmail.com> > Cc: Wei Yang <richardw.yang@linux.intel.com> > Cc: Will Deacon <will@kernel.org> > Cc: Yoshinori Sato <ysato@users.sourceforge.jp> > Cc: Yu Zhao <yuzhao@google.com> > Cc: <stable@vger.kernel.org> [5.0+] > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > --- > > mm/memremap.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > --- a/mm/memremap.c~mm-memunmap-dont-access-uninitialized-memmap-in-memunmap_pages > +++ a/mm/memremap.c > @@ -103,6 +103,7 @@ static void dev_pagemap_cleanup(struct d > void memunmap_pages(struct dev_pagemap *pgmap) > { > struct resource *res = &pgmap->res; > + struct page *first_page; > unsigned long pfn; > int nid; > > @@ -111,14 +112,16 @@ void memunmap_pages(struct dev_pagemap * > put_page(pfn_to_page(pfn)); > dev_pagemap_cleanup(pgmap); > > + /* make sure to access a memmap that was actually initialized */ > + first_page = pfn_to_page(pfn_first(pgmap)); > + > /* pages are dead and unused, undo the arch mapping */ > - nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start))); > + nid = page_to_nid(first_page); > > mem_hotplug_begin(); > if (pgmap->type == MEMORY_DEVICE_PRIVATE) { > - pfn = PHYS_PFN(res->start); > - __remove_pages(page_zone(pfn_to_page(pfn)), pfn, > - PHYS_PFN(resource_size(res)), NULL); > + __remove_pages(page_zone(first_page), PHYS_PFN(res->start), > + PHYS_PFN(resource_size(res)), NULL); > } else { > arch_remove_memory(nid, res->start, resource_size(res), > pgmap_altmap(pgmap)); > _
On 21.10.19 10:26, Michal Hocko wrote: > Has this been properly reviewed? I do not see any Acks nor Reviewed-bys. > As I modified this patch while carrying it along, it at least has my implicit Ack/RB.
On Mon 21-10-19 10:28:16, David Hildenbrand wrote: > On 21.10.19 10:26, Michal Hocko wrote: > > Has this been properly reviewed? I do not see any Acks nor Reviewed-bys. > > > > As I modified this patch while carrying it along, it at least has my > implicit Ack/RB. OK, thanks!
--- a/mm/memremap.c~mm-memunmap-dont-access-uninitialized-memmap-in-memunmap_pages +++ a/mm/memremap.c @@ -103,6 +103,7 @@ static void dev_pagemap_cleanup(struct d void memunmap_pages(struct dev_pagemap *pgmap) { struct resource *res = &pgmap->res; + struct page *first_page; unsigned long pfn; int nid; @@ -111,14 +112,16 @@ void memunmap_pages(struct dev_pagemap * put_page(pfn_to_page(pfn)); dev_pagemap_cleanup(pgmap); + /* make sure to access a memmap that was actually initialized */ + first_page = pfn_to_page(pfn_first(pgmap)); + /* pages are dead and unused, undo the arch mapping */ - nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start))); + nid = page_to_nid(first_page); mem_hotplug_begin(); if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - pfn = PHYS_PFN(res->start); - __remove_pages(page_zone(pfn_to_page(pfn)), pfn, - PHYS_PFN(resource_size(res)), NULL); + __remove_pages(page_zone(first_page), PHYS_PFN(res->start), + PHYS_PFN(resource_size(res)), NULL); } else { arch_remove_memory(nid, res->start, resource_size(res), pgmap_altmap(pgmap));