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2021-10-06mm: don't allow oversized kvmalloc() callsLinus Torvalds1-0/+4
commit 7661809d493b426e979f39ab512e3adf41fbcc69 upstream. 'kvmalloc()' is a convenience function for people who want to do a kmalloc() but fall back on vmalloc() if there aren't enough physically contiguous pages, or if the allocation is larger than what kmalloc() supports. However, let's make sure it doesn't get _too_ easy to do crazy things with it. In particular, don't allow big allocations that could be due to integer overflow or underflow. So make sure the allocation size fits in an 'int', to protect against trivial integer conversion issues. Acked-by: Willy Tarreau <w@1wt.eu> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-30mm: fix uninitialized use in overcommit_policy_handlerChen Jun1-2/+2
commit bcbda81020c3ee77e2c098cadf3e84f99ca3de17 upstream. We get an unexpected value of /proc/sys/vm/overcommit_memory after running the following program: int main() { int fd = open("/proc/sys/vm/overcommit_memory", O_RDWR); write(fd, "1", 1); write(fd, "2", 1); close(fd); } write(fd, "2", 1) will pass *ppos = 1 to proc_dointvec_minmax. proc_dointvec_minmax will return 0 without setting new_policy. t.data = &new_policy; ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos) -->do_proc_dointvec -->__do_proc_dointvec if (write) { if (proc_first_pos_non_zero_ignore(ppos, table)) goto out; sysctl_overcommit_memory = new_policy; so sysctl_overcommit_memory will be set to an uninitialized value. Check whether new_policy has been changed by proc_dointvec_minmax. Link: https://lkml.kernel.org/r/20210923020524.13289-1-chenjun102@huawei.com Fixes: 56f3547bfa4d ("mm: adjust vm_committed_as_batch according to vm overcommit policy") Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Feng Tang <feng.tang@intel.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Rui Xiang <rui.xiang@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range()David Hildenbrand1-2/+2
commit 7cf209ba8a86410939a24cb1aeb279479a7e0ca6 upstream. Patch series "mm/memory_hotplug: preparatory patches for new online policy and memory" These are all cleanups and one fix previously sent as part of [1]: [PATCH v1 00/12] mm/memory_hotplug: "auto-movable" online policy and memory groups. These patches make sense even without the other series, therefore I pulled them out to make the other series easier to digest. [1] https://lkml.kernel.org/r/20210607195430.48228-1-david@redhat.com This patch (of 4): Checkpatch complained on a follow-up patch that we are using "unsigned" here, which defaults to "unsigned int" and checkpatch is correct. As we will search for a fitting zone using the wrong pfn, we might end up onlining memory to one of the special kernel zones, such as ZONE_DMA, which can end badly as the onlined memory does not satisfy properties of these zones. Use "unsigned long" instead, just as we do in other places when handling PFNs. This can bite us once we have physical addresses in the range of multiple TB. Link: https://lkml.kernel.org/r/20210712124052.26491-2-david@redhat.com Fixes: e5e689302633 ("mm, memory_hotplug: display allowed zones in the preferred ordering") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Rapoport <rppt@kernel.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: virtualization@lists.linux-foundation.org Cc: Andy Lutomirski <luto@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Jiang <dave.jiang@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: Joe Perches <joe@perches.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pierre Morel <pmorel@linux.ibm.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Rich Felker <dalias@libc.org> Cc: Scott Cheloha <cheloha@linux.ibm.com> Cc: Sergei Trofimovich <slyfox@gentoo.org> Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-18mm,vmscan: fix divide by zero in get_scan_countRik van Riel1-1/+1
commit 32d4f4b782bb8f0ceb78c6b5dc46eb577ae25bf7 upstream. Commit f56ce412a59d ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim") introduced a divide by zero corner case when oomd is being used in combination with cgroup memory.low protection. When oomd decides to kill a cgroup, it will force the cgroup memory to be reclaimed after killing the tasks, by writing to the memory.max file for that cgroup, forcing the remaining page cache and reclaimable slab to be reclaimed down to zero. Previously, on cgroups with some memory.low protection that would result in the memory being reclaimed down to the memory.low limit, or likely not at all, having the page cache reclaimed asynchronously later. With f56ce412a59d the oomd write to memory.max tries to reclaim all the way down to zero, which may race with another reclaimer, to the point of ending up with the divide by zero below. This patch implements the obvious fix. Link: https://lkml.kernel.org/r/20210826220149.058089c6@imladris.surriel.com Fixes: f56ce412a59d ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim") Signed-off-by: Rik van Riel <riel@surriel.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Chris Down <chris@chrisdown.name> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-18mm/hmm: bypass devmap pte when all pfn requested flags are fulfilledLi Zhijian1-1/+4
commit 4b42fb213678d2b6a9eeea92a9be200f23e49583 upstream. Previously, we noticed the one rpma example was failed[1] since commit 36f30e486dce ("IB/core: Improve ODP to use hmm_range_fault()"), where it will use ODP feature to do RDMA WRITE between fsdax files. After digging into the code, we found hmm_vma_handle_pte() will still return EFAULT even though all the its requesting flags has been fulfilled. That's because a DAX page will be marked as (_PAGE_SPECIAL | PAGE_DEVMAP) by pte_mkdevmap(). Link: https://github.com/pmem/rpma/issues/1142 [1] Link: https://lkml.kernel.org/r/20210830094232.203029-1-lizhijian@cn.fujitsu.com Fixes: 405506274922 ("mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling") Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-18hugetlb: fix hugetlb cgroup refcounting during vma splitMike Kravetz1-1/+3
commit 09a26e832705fdb7a9484495b71a05e0bbc65207 upstream. Guillaume Morin reported hitting the following WARNING followed by GPF or NULL pointer deference either in cgroups_destroy or in the kill_css path.: percpu ref (css_release) <= 0 (-1) after switching to atomic WARNING: CPU: 23 PID: 130 at lib/percpu-refcount.c:196 percpu_ref_switch_to_atomic_rcu+0x127/0x130 CPU: 23 PID: 130 Comm: ksoftirqd/23 Kdump: loaded Tainted: G O 5.10.60 #1 RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x127/0x130 Call Trace: rcu_core+0x30f/0x530 rcu_core_si+0xe/0x10 __do_softirq+0x103/0x2a2 run_ksoftirqd+0x2b/0x40 smpboot_thread_fn+0x11a/0x170 kthread+0x10a/0x140 ret_from_fork+0x22/0x30 Upon further examination, it was discovered that the css structure was associated with hugetlb reservations. For private hugetlb mappings the vma points to a reserve map that contains a pointer to the css. At mmap time, reservations are set up and a reference to the css is taken. This reference is dropped in the vma close operation; hugetlb_vm_op_close. However, if a vma is split no additional reference to the css is taken yet hugetlb_vm_op_close will be called twice for the split vma resulting in an underflow. Fix by taking another reference in hugetlb_vm_op_open. Note that the reference is only taken for the owner of the reserve map. In the more common fork case, the pointer to the reserve map is cleared for non-owning vmas. Link: https://lkml.kernel.org/r/20210830215015.155224-1-mike.kravetz@oracle.com Fixes: e9fe92ae0cd2 ("hugetlb_cgroup: add reservation accounting for private mappings") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Guillaume Morin <guillaume@morinfr.org> Suggested-by: Guillaume Morin <guillaume@morinfr.org> Tested-by: Guillaume Morin <guillaume@morinfr.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-12mm/page_alloc: speed up the iteration of max_orderMuchun Song1-4/+4
commit 7ad69832f37e3cea8557db6df7c793905f1135e8 upstream. When we free a page whose order is very close to MAX_ORDER and greater than pageblock_order, it wastes some CPU cycles to increase max_order to MAX_ORDER one by one and check the pageblock migratetype of that page repeatedly especially when MAX_ORDER is much larger than pageblock_order. We also should not be checking migratetype of buddy when "order == MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition. With the new check, we don't need the max_order check anymore, so we replace it. Also adjust max_order initialization so that it's lower by one than previously, which makes the code hopefully more clear. Link: https://lkml.kernel.org/r/20201204155109.55451-1-songmuchun@bytedance.com Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-26mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaimJohannes Weiner1-8/+19
[ Upstream commit f56ce412a59d7d938b81de8878faef128812482c ] We've noticed occasional OOM killing when memory.low settings are in effect for cgroups. This is unexpected and undesirable as memory.low is supposed to express non-OOMing memory priorities between cgroups. The reason for this is proportional memory.low reclaim. When cgroups are below their memory.low threshold, reclaim passes them over in the first round, and then retries if it couldn't find pages anywhere else. But when cgroups are slightly above their memory.low setting, page scan force is scaled down and diminished in proportion to the overage, to the point where it can cause reclaim to fail as well - only in that case we currently don't retry, and instead trigger OOM. To fix this, hook proportional reclaim into the same retry logic we have in place for when cgroups are skipped entirely. This way if reclaim fails and some cgroups were scanned with diminished pressure, we'll try another full-force cycle before giving up and OOMing. [akpm@linux-foundation.org: coding-style fixes] Link: https://lkml.kernel.org/r/20210817180506.220056-1-hannes@cmpxchg.org Fixes: 9783aa9917f8 ("mm, memcg: proportional memory.{low,min} reclaim") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Leon Yang <lnyng@fb.com> Reviewed-by: Rik van Riel <riel@surriel.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> [5.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28memblock: make for_each_mem_range() traverse MEMBLOCK_HOTPLUG regionsMike Rapoport1-1/+2
commit 79e482e9c3ae86e849c701c846592e72baddda5a upstream. Commit b10d6bca8720 ("arch, drivers: replace for_each_membock() with for_each_mem_range()") didn't take into account that when there is movable_node parameter in the kernel command line, for_each_mem_range() would skip ranges marked with MEMBLOCK_HOTPLUG. The page table setup code in POWER uses for_each_mem_range() to create the linear mapping of the physical memory and since the regions marked as MEMORY_HOTPLUG are skipped, they never make it to the linear map. A later access to the memory in those ranges will fail: BUG: Unable to handle kernel data access on write at 0xc000000400000000 Faulting instruction address: 0xc00000000008a3c0 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 53 Comm: kworker/u2:0 Not tainted 5.13.0 #7 NIP: c00000000008a3c0 LR: c0000000003c1ed8 CTR: 0000000000000040 REGS: c000000008a57770 TRAP: 0300 Not tainted (5.13.0) MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 84222202 XER: 20040000 CFAR: c0000000003c1ed4 DAR: c000000400000000 DSISR: 42000000 IRQMASK: 0 GPR00: c0000000003c1ed8 c000000008a57a10 c0000000019da700 c000000400000000 GPR04: 0000000000000280 0000000000000180 0000000000000400 0000000000000200 GPR08: 0000000000000100 0000000000000080 0000000000000040 0000000000000300 GPR12: 0000000000000380 c000000001bc0000 c0000000001660c8 c000000006337e00 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000040000000 0000000020000000 c000000001a81990 c000000008c30000 GPR24: c000000008c20000 c000000001a81998 000fffffffff0000 c000000001a819a0 GPR28: c000000001a81908 c00c000001000000 c000000008c40000 c000000008a64680 NIP clear_user_page+0x50/0x80 LR __handle_mm_fault+0xc88/0x1910 Call Trace: __handle_mm_fault+0xc44/0x1910 (unreliable) handle_mm_fault+0x130/0x2a0 __get_user_pages+0x248/0x610 __get_user_pages_remote+0x12c/0x3e0 get_arg_page+0x54/0xf0 copy_string_kernel+0x11c/0x210 kernel_execve+0x16c/0x220 call_usermodehelper_exec_async+0x1b0/0x2f0 ret_from_kernel_thread+0x5c/0x70 Instruction dump: 79280fa4 79271764 79261f24 794ae8e2 7ca94214 7d683a14 7c893a14 7d893050 7d4903a6 60000000 60000000 60000000 <7c001fec> 7c091fec 7c081fec 7c051fec ---[ end trace 490b8c67e6075e09 ]--- Making for_each_mem_range() include MEMBLOCK_HOTPLUG regions in the traversal fixes this issue. Link: https://bugzilla.redhat.com/show_bug.cgi?id=1976100 Link: https://lkml.kernel.org/r/20210712071132.20902-1-rppt@kernel.org Fixes: b10d6bca8720 ("arch, drivers: replace for_each_membock() with for_each_mem_range()") Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Tested-by: Greg Kurz <groug@kaod.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> [5.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25Revert "mm/shmem: fix shmem_swapin() race with swapoff"Greg Kroah-Hartman1-13/+1
This reverts commit a533a21b692fc15a6aadfa827b29c7d9989109ca which is commit 2efa33fc7f6ec94a3a538c1a264273c889be2b36 upstream. It should not have been added to the stable trees, sorry about that. Link: https://lore.kernel.org/r/YPVgaY6uw59Fqg5x@casper.infradead.org Reported-by: From: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Ying Huang <ying.huang@intel.com> Cc: Alex Shi <alexs@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25mm/page_alloc: fix memory map initialization for descending nodesMike Rapoport1-39/+67
commit 122e093c1734361dedb64f65c99b93e28e4624f4 upstream. On systems with memory nodes sorted in descending order, for instance Dell Precision WorkStation T5500, the struct pages for higher PFNs and respectively lower nodes, could be overwritten by the initialization of struct pages corresponding to the holes in the memory sections. For example for the below memory layout [ 0.245624] Early memory node ranges [ 0.248496] node 1: [mem 0x0000000000001000-0x0000000000090fff] [ 0.251376] node 1: [mem 0x0000000000100000-0x00000000dbdf8fff] [ 0.254256] node 1: [mem 0x0000000100000000-0x0000001423ffffff] [ 0.257144] node 0: [mem 0x0000001424000000-0x0000002023ffffff] the range 0x1424000000 - 0x1428000000 in the beginning of node 0 starts in the middle of a section and will be considered as a hole during the initialization of the last section in node 1. The wrong initialization of the memory map causes panic on boot when CONFIG_DEBUG_VM is enabled. Reorder loop order of the memory map initialization so that the outer loop will always iterate over populated memory regions in the ascending order and the inner loop will select the zone corresponding to the PFN range. This way initialization of the struct pages for the memory holes will be always done for the ranges that are actually not populated. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/YNXlMqBbL+tBG7yq@kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=213073 Link: https://lkml.kernel.org/r/20210624062305.10940-1-rppt@kernel.org Fixes: 0740a50b9baa ("mm/page_alloc.c: refactor initialization of struct page for holes in memory layout") Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Boris Petkov <bp@alien8.de> Cc: Robert Shteynfeld <robert.shteynfeld@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [rppt: tweak for compatibility with IA64's override of memmap_init] Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25mm/userfaultfd: fix uffd-wp special cases for fork()Peter Xu2-25/+27
commit 8f34f1eac3820fc2722e5159acceb22545b30b0d upstream. We tried to do something similar in b569a1760782 ("userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork") previously, but it's not doing it all right.. A few fixes around the code path: 1. We were referencing VM_UFFD_WP vm_flags on the _old_ vma rather than the new vma. That's overlooked in b569a1760782, so it won't work as expected. Thanks to the recent rework on fork code (7a4830c380f3a8b3), we can easily get the new vma now, so switch the checks to that. 2. Dropping the uffd-wp bit in copy_huge_pmd() could be wrong if the huge pmd is a migration huge pmd. When it happens, instead of using pmd_uffd_wp(), we should use pmd_swp_uffd_wp(). The fix is simply to handle them separately. 3. Forget to carry over uffd-wp bit for a write migration huge pmd entry. This also happens in copy_huge_pmd(), where we converted a write huge migration entry into a read one. 4. In copy_nonpresent_pte(), drop uffd-wp if necessary for swap ptes. 5. In copy_present_page() when COW is enforced when fork(), we also need to pass over the uffd-wp bit if VM_UFFD_WP is armed on the new vma, and when the pte to be copied has uffd-wp bit set. Remove the comment in copy_present_pte() about this. It won't help a huge lot to only comment there, but comment everywhere would be an overkill. Let's assume the commit messages would help. [peterx@redhat.com: fix a few thp pmd missing uffd-wp bit] Link: https://lkml.kernel.org/r/20210428225030.9708-4-peterx@redhat.com Link: https://lkml.kernel.org/r/20210428225030.9708-3-peterx@redhat.com Fixes: b569a1760782f ("userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork") Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joe Perches <joe@perches.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Oliver Upton <oupton@google.com> Cc: Shaohua Li <shli@fb.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Wang Qing <wangqing@vivo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25mm/thp: simplify copying of huge zero page pmd when forkPeter Xu1-6/+3
commit 5fc7a5f6fd04bc18f309d9f979b32ef7d1d0a997 upstream. Patch series "mm/uffd: Misc fix for uffd-wp and one more test". This series tries to fix some corner case bugs for uffd-wp on either thp or fork(). Then it introduced a new test with pagemap/pageout. Patch layout: Patch 1: cleanup for THP, it'll slightly simplify the follow up patches Patch 2-4: misc fixes for uffd-wp here and there; please refer to each patch Patch 5: add pagemap support for uffd-wp Patch 6: add pagemap/pageout test for uffd-wp The last test introduced can also verify some of the fixes in previous patches, as the test will fail without the fixes. However it's not easy to verify all the changes in patch 2-4, but hopefully they can still be properly reviewed. Note that if considering the ongoing uffd-wp shmem & hugetlbfs work, patch 5 will be incomplete as it's missing e.g. hugetlbfs part or the special swap pte detection. However that's not needed in this series, and since that series is still during review, this series does not depend on that one (the last test only runs with anonymous memory, not file-backed). So this series can be merged even before that series. This patch (of 6): Huge zero page is handled in a special path in copy_huge_pmd(), however it should share most codes with a normal thp page. Trying to share more code with it by removing the special path. The only leftover so far is the huge zero page refcounting (mm_get_huge_zero_page()), because that's separately done with a global counter. This prepares for a future patch to modify the huge pmd to be installed, so that we don't need to duplicate it explicitly into huge zero page case too. Link: https://lkml.kernel.org/r/20210428225030.9708-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20210428225030.9708-2-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Mike Kravetz <mike.kravetz@oracle.com>, peterx@redhat.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Brian Geffon <bgeffon@google.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Oliver Upton <oupton@google.com> Cc: Shaohua Li <shli@fb.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Wang Qing <wangqing@vivo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25Revert "swap: fix do_swap_page() race with swapoff"Greg Kroah-Hartman1-9/+2
This reverts commit 8e4af3917bfc5e82f8010417c12b755ef256fa5e which is commit 2799e77529c2a25492a4395db93996e3dacd762d upstream. It should not have been added to the stable trees, sorry about that. Link: https://lore.kernel.org/r/YPVgaY6uw59Fqg5x@casper.infradead.org Reported-by: From: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Ying Huang <ying.huang@intel.com> Cc: Alex Shi <alexs@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-19mm,hwpoison: return -EBUSY when migration failsOscar Salvador1-3/+3
commit 3f4b815a439adfb8f238335612c4b28bc10084d8 upstream. Currently, we return -EIO when we fail to migrate the page. Migrations' failures are rather transient as they can happen due to several reasons, e.g: high page refcount bump, mapping->migrate_page failing etc. All meaning that at that time the page could not be migrated, but that has nothing to do with an EIO error. Let us return -EBUSY instead, as we do in case we failed to isolate the page. While are it, let us remove the "ret" print as its value does not change. Link: https://lkml.kernel.org/r/20201209092818.30417-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14mm/z3fold: use release_z3fold_page_locked() to release locked z3fold pageMiaohe Lin1-1/+1
[ Upstream commit 28473d91ff7f686d58047ff55f2fa98ab59114a4 ] We should use release_z3fold_page_locked() to release z3fold page when it's locked, although it looks harmless to use release_z3fold_page() now. Link: https://lkml.kernel.org/r/20210619093151.1492174-7-linmiaohe@huawei.com Fixes: dcf5aedb24f8 ("z3fold: stricter locking and more careful reclaim") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Hillf Danton <hdanton@sina.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/z3fold: fix potential memory leak in z3fold_destroy_pool()Miaohe Lin1-0/+1
[ Upstream commit dac0d1cfda56472378d330b1b76b9973557a7b1d ] There is a memory leak in z3fold_destroy_pool() as it forgets to free_percpu pool->unbuddied. Call free_percpu for pool->unbuddied to fix this issue. Link: https://lkml.kernel.org/r/20210619093151.1492174-6-linmiaohe@huawei.com Fixes: d30561c56f41 ("z3fold: use per-cpu unbuddied lists") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Hillf Danton <hdanton@sina.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14hugetlb: remove prep_compound_huge_page cleanupMike Kravetz1-19/+10
[ Upstream commit 48b8d744ea841b8adf8d07bfe7a2d55f22e4d179 ] Patch series "Fix prep_compound_gigantic_page ref count adjustment". These patches address the possible race between prep_compound_gigantic_page and __page_cache_add_speculative as described by Jann Horn in [1]. The first patch simply removes the unnecessary/obsolete helper routine prep_compound_huge_page to make the actual fix a little simpler. The second patch is the actual fix and has a detailed explanation in the commit message. This potential issue has existed for almost 10 years and I am unaware of anyone actually hitting the race. I did not cc stable, but would be happy to squash the patches and send to stable if anyone thinks that is a good idea. [1] https://lore.kernel.org/linux-mm/CAG48ez23q0Jy9cuVnwAe7t_fdhMk2S7N5Hdi-GLcCeq5bsfLxw@mail.gmail.com/ This patch (of 2): I could not think of a reliable way to recreate the issue for testing. Rather, I 'simulated errors' to exercise all the error paths. The routine prep_compound_huge_page is a simple wrapper to call either prep_compound_gigantic_page or prep_compound_page. However, it is only called from gather_bootmem_prealloc which only processes gigantic pages. Eliminate the routine and call prep_compound_gigantic_page directly. Link: https://lkml.kernel.org/r/20210622021423.154662-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20210622021423.154662-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Youquan Song <youquan.song@intel.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/hugetlb: remove redundant check in preparing and destroying gigantic pageYanfei Xu1-5/+2
[ Upstream commit 5291c09b3edb657f23c1939750c702ba2d74932f ] Gigantic page is a compound page and its order is more than 1. Thus it must be available for hpage_pincount. Let's remove the redundant check for gigantic page. Link: https://lkml.kernel.org/r/20210202112002.73170-1-yanfei.xu@windriver.com Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/hugetlb: use helper huge_page_order and pages_per_huge_pageMiaohe Lin1-2/+2
[ Upstream commit c78a7f3639932c48b4e1d329fc80fd26aa1a2fa3 ] Since commit a5516438959d ("hugetlb: modular state for hugetlb page size"), we can use huge_page_order to access hstate->order and pages_per_huge_page to fetch the pages per huge page. But gather_bootmem_prealloc() forgot to use it. Link: https://lkml.kernel.org/r/20210114114435.40075-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/huge_memory.c: don't discard hugepage if other processes are mapping itMiaohe Lin1-1/+1
[ Upstream commit babbbdd08af98a59089334eb3effbed5a7a0cf7f ] If other processes are mapping any other subpages of the hugepage, i.e. in pte-mapped thp case, page_mapcount() will return 1 incorrectly. Then we would discard the page while other processes are still mapping it. Fix it by using total_mapcount() which can tell whether other processes are still mapping it. Link: https://lkml.kernel.org/r/20210511134857.1581273-6-linmiaohe@huawei.com Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called") Reviewed-by: Yang Shi <shy828301@gmail.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Rik van Riel <riel@surriel.com> Cc: Song Liu <songliubraving@fb.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/huge_memory.c: add missing read-only THP checking in ↵Miaohe Lin3-6/+12
transparent_hugepage_enabled() [ Upstream commit e6be37b2e7bddfe0c76585ee7c7eee5acc8efeab ] Since commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS"), read-only THP file mapping is supported. But it forgot to add checking for it in transparent_hugepage_enabled(). To fix it, we add checking for read-only THP file mapping and also introduce helper transhuge_vma_enabled() to check whether thp is enabled for specified vma to reduce duplicated code. We rename transparent_hugepage_enabled to transparent_hugepage_active to make the code easier to follow as suggested by David Hildenbrand. [linmiaohe@huawei.com: define transhuge_vma_enabled next to transhuge_vma_suitable] Link: https://lkml.kernel.org/r/20210514093007.4117906-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210511134857.1581273-4-linmiaohe@huawei.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Rik van Riel <riel@surriel.com> Cc: Song Liu <songliubraving@fb.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/pmem: avoid inserting hugepage PTE entry with fsdax if hugepage support ↵Aneesh Kumar K.V1-1/+5
is disabled [ Upstream commit bae84953815793f68ddd8edeadd3f4e32676a2c8 ] Differentiate between hardware not supporting hugepages and user disabling THP via 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' For the devdax namespace, the kernel handles the above via the supported_alignment attribute and failing to initialize the namespace if the namespace align value is not supported on the platform. For the fsdax namespace, the kernel will continue to initialize the namespace. This can result in the kernel creating a huge pte entry even though the hardware don't support the same. We do want hugepage support with pmem even if the end-user disabled THP via sysfs file (/sys/kernel/mm/transparent_hugepage/enabled). Hence differentiate between hardware/firmware lacking support vs user-controlled disable of THP and prevent a huge fault if the hardware lacks hugepage support. Link: https://lkml.kernel.org/r/20210205023956.417587-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/page_alloc: fix counting of managed_pagesLiu Shixin1-6/+6
[ Upstream commit f7ec104458e00d27a190348ac3a513f3df3699a4 ] commit f63661566fad ("mm/page_alloc.c: clear out zone->lowmem_reserve[] if the zone is empty") clears out zone->lowmem_reserve[] if zone is empty. But when zone is not empty and sysctl_lowmem_reserve_ratio[i] is set to zero, zone_managed_pages(zone) is not counted in the managed_pages either. This is inconsistent with the description of lowmem_reserve, so fix it. Link: https://lkml.kernel.org/r/20210527125707.3760259-1-liushixin2@huawei.com Fixes: f63661566fad ("mm/page_alloc.c: clear out zone->lowmem_reserve[] if the zone is empty") Signed-off-by: Liu Shixin <liushixin2@huawei.com> Reported-by: yangerkun <yangerkun@huawei.com> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm: page_alloc: refactor setup_per_zone_lowmem_reserve()Lorenzo Stoakes1-21/+14
[ Upstream commit 470c61d70299b1826f56ff5fede10786798e3c14 ] setup_per_zone_lowmem_reserve() iterates through each zone setting zone->lowmem_reserve[j] = 0 (where j is the zone's index) then iterates backwards through all preceding zones, setting lower_zone->lowmem_reserve[j] = sum(managed pages of higher zones) / lowmem_reserve_ratio[idx] for each (where idx is the lower zone's index). If the lower zone has no managed pages or its ratio is 0 then all of its lowmem_reserve[] entries are effectively zeroed. As these arrays are only assigned here and all lowmem_reserve[] entries for index < this zone's index are implicitly assumed to be 0 (as these are specifically output in show_free_areas() and zoneinfo_show_print() for example) there is no need to additionally zero index == this zone's index too. This patch avoids zeroing unnecessarily. Rather than iterating through zones and setting lowmem_reserve[j] for each lower zone this patch reverse the process and populates each zone's lowmem_reserve[] values in ascending order. This clarifies what is going on especially in the case of zero managed pages or ratio which is now explicitly shown to clear these values. Link: https://lkml.kernel.org/r/20201129162758.115907-1-lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm: memcg/slab: properly set up gfp flags for objcg pointer arrayWaiman Long2-1/+8
[ Upstream commit 41eb5df1cbc9b302fc263ad7c9f38cfc38b4df61 ] Patch series "mm: memcg/slab: Fix objcg pointer array handling problem", v4. Since the merging of the new slab memory controller in v5.9, the page structure stores a pointer to objcg pointer array for slab pages. When the slab has no used objects, it can be freed in free_slab() which will call kfree() to free the objcg pointer array in memcg_alloc_page_obj_cgroups(). If it happens that the objcg pointer array is the last used object in its slab, that slab may then be freed which may caused kfree() to be called again. With the right workload, the slab cache may be set up in a way that allows the recursive kfree() calling loop to nest deep enough to cause a kernel stack overflow and panic the system. In fact, we have a reproducer that can cause kernel stack overflow on a s390 system involving kmalloc-rcl-256 and kmalloc-rcl-128 slabs with the following kfree() loop recursively called 74 times: [ 285.520739] [<000000000ec432fc>] kfree+0x4bc/0x560 [ 285.520740] [<000000000ec43466>] __free_slab+0xc6/0x228 [ 285.520741] [<000000000ec41fc2>] __slab_free+0x3c2/0x3e0 [ 285.520742] [<000000000ec432fc>] kfree+0x4bc/0x560 : While investigating this issue, I also found an issue on the allocation side. If the objcg pointer array happen to come from the same slab or a circular dependency linkage is formed with multiple slabs, those affected slabs can never be freed again. This patch series addresses these two issues by introducing a new set of kmalloc-cg-<n> caches split from kmalloc-<n> caches. The new set will only contain non-reclaimable and non-dma objects that are accounted in memory cgroups whereas the old set are now for unaccounted objects only. By making this split, all the objcg pointer arrays will come from the kmalloc-<n> caches, but those caches will never hold any objcg pointer array. As a result, deeply nested kfree() call and the unfreeable slab problems are now gone. This patch (of 4): Since the merging of the new slab memory controller in v5.9, the page structure may store a pointer to obj_cgroup pointer array for slab pages. Currently, only the __GFP_ACCOUNT bit is masked off. However, the array is not readily reclaimable and doesn't need to come from the DMA buffer. So those GFP bits should be masked off as well. Do the flag bit clearing at memcg_alloc_page_obj_cgroups() to make sure that it is consistently applied no matter where it is called. Link: https://lkml.kernel.org/r/20210505200610.13943-1-longman@redhat.com Link: https://lkml.kernel.org/r/20210505200610.13943-2-longman@redhat.com Fixes: 286e04b8ed7a ("mm: memcg/slab: allocate obj_cgroups for non-root slab pages") Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14mm/shmem: fix shmem_swapin() race with swapoffMiaohe Lin1-1/+13
[ Upstream commit 2efa33fc7f6ec94a3a538c1a264273c889be2b36 ] When I was investigating the swap code, I found the below possible race window: CPU 1 CPU 2 ----- ----- shmem_swapin swap_cluster_readahead if (likely(si->flags & (SWP_BLKDEV | SWP_FS_OPS))) { swapoff .. si->swap_file = NULL; .. struct inode *inode = si->swap_file->f_mapping->host;[oops!] Close this race window by using get/put_swap_device() to guard against concurrent swapoff. Link: https://lkml.kernel.org/r/20210426123316.806267-5-linmiaohe@huawei.com Fixes: 8fd2e0b505d1 ("mm: swap: check if swap backing device is congested or not") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Alex Shi <alexs@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14swap: fix do_swap_page() race with swapoffMiaohe Lin1-2/+9
[ Upstream commit 2799e77529c2a25492a4395db93996e3dacd762d ] When I was investigating the swap code, I found the below possible race window: CPU 1 CPU 2 ----- ----- do_swap_page if (data_race(si->flags & SWP_SYNCHRONOUS_IO) swap_readpage if (data_race(sis->flags & SWP_FS_OPS)) { swapoff .. p->swap_file = NULL; .. struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping;[oops!] Note that for the pages that are swapped in through swap cache, this isn't an issue. Because the page is locked, and the swap entry will be marked with SWAP_HAS_CACHE, so swapoff() can not proceed until the page has been unlocked. Fix this race by using get/put_swap_device() to guard against concurrent swapoff. Link: https://lkml.kernel.org/r/20210426123316.806267-3-linmiaohe@huawei.com Fixes: 0bcac06f27d7 ("mm,swap: skip swapcache for swapin of synchronous device") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Alex Shi <alexs@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Lin