diff mbox series

[v2,32/32] perf/core: Allow pte_offset_map() to fail

Message ID	a194441b-63f3-adb6-5964-7ca3171ae7c2@google.com
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Date: Thu, 8 Jun 2023 18:53:23 -0700 (PDT) From: Hugh Dickins <hughd@google.com> To: Andrew Morton <akpm@linux-foundation.org> cc: Mike Kravetz <mike.kravetz@oracle.com>, Mike Rapoport <rppt@kernel.org>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Matthew Wilcox <willy@infradead.org>, David Hildenbrand <david@redhat.com>, Suren Baghdasaryan <surenb@google.com>, Qi Zheng <zhengqi.arch@bytedance.com>, Yang Shi <shy828301@gmail.com>, Mel Gorman <mgorman@techsingularity.net>, Peter Xu <peterx@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>, Alistair Popple <apopple@nvidia.com>, Ralph Campbell <rcampbell@nvidia.com>, Ira Weiny <ira.weiny@intel.com>, Steven Price <steven.price@arm.com>, SeongJae Park <sj@kernel.org>, Lorenzo Stoakes <lstoakes@gmail.com>, Huang Ying <ying.huang@intel.com>, Naoya Horiguchi <naoya.horiguchi@nec.com>, Christophe Leroy <christophe.leroy@csgroup.eu>, Zack Rusin <zackr@vmware.com>, Jason Gunthorpe <jgg@ziepe.ca>, Axel Rasmussen <axelrasmussen@google.com>, Anshuman Khandual <anshuman.khandual@arm.com>, Pasha Tatashin <pasha.tatashin@soleen.com>, Miaohe Lin <linmiaohe@huawei.com>, Minchan Kim <minchan@kernel.org>, Christoph Hellwig <hch@infradead.org>, Song Liu <song@kernel.org>, Thomas Hellstrom <thomas.hellstrom@linux.intel.com>, Ryan Roberts <ryan.roberts@arm.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 32/32] perf/core: Allow pte_offset_map() to fail In-Reply-To: <c1c9a74a-bc5b-15ea-e5d2-8ec34bc921d@google.com> Message-ID: <a194441b-63f3-adb6-5964-7ca3171ae7c2@google.com> References: <c1c9a74a-bc5b-15ea-e5d2-8ec34bc921d@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk
Series	mm: allow pte_offset_map[_lock]() to fail \| [v2,00/32] mm: allow pte_offset_map[_lock]() to fail [v2,01/32] mm: use pmdp_get_lockless() without surplus barrier() [v2,02/32] mm/migrate: remove cruft from migration_entry_wait()s [v2,03/32] mm/pgtable: kmap_local_page() instead of kmap_atomic() [v2,04/32] mm/pgtable: allow pte_offset_map[_lock]() to fail [v2,05/32] mm/filemap: allow pte_offset_map_lock() to fail [v2,06/32] mm/page_vma_mapped: delete bogosity in page_vma_mapped_walk() [v2,07/32] mm/page_vma_mapped: reformat map_pte() with less indentation [v2,08/32] mm/page_vma_mapped: pte_offset_map_nolock() not pte_lockptr() [v2,09/32] mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails [v2,10/32] mm/pagewalk: walk_pte_range() allow for pte_offset_map() [v2,11/32] mm/vmwgfx: simplify pmd & pud mapping dirty helpers [v2,12/32] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel() [v2,13/32] mm/hmm: retry if pte_offset_map() fails [v2,14/32] mm/userfaultfd: retry if pte_offset_map() fails [v2,15/32] mm/userfaultfd: allow pte_offset_map_lock() to fail [v2,16/32] mm/debug_vm_pgtable,page_table_check: warn pte map fails [v2,17/32] mm/various: give up if pte_offset_map[_lock]() fails [v2,18/32] mm/mprotect: delete pmd_none_or_clear_bad_unless_trans_huge() [v2,19/32] mm/mremap: retry if either pte_offset_map_*lock() fails [v2,20/32] mm/madvise: clean up pte_offset_map_lock() scans [v2,21/32] mm/madvise: clean up force_shm_swapin_readahead() [v2,22/32] mm/swapoff: allow pte_offset_map[_lock]() to fail [v2,23/32] mm/mglru: allow pte_offset_map_nolock() to fail [v2,24/32] mm/migrate_device: allow pte_offset_map_lock() to fail [v2,25/32] mm/gup: remove FOLL_SPLIT_PMD use of pmd_trans_unstable() [v2,26/32] mm/huge_memory: split huge pmd under one pte_offset_map() [v2,27/32] mm/khugepaged: allow pte_offset_map[_lock]() to fail [v2,28/32] mm/memory: allow pte_offset_map[_lock]() to fail [v2,29/32] mm/memory: handle_pte_fault() use pte_offset_map_nolock() [v2,30/32] mm/pgtable: delete pmd_trans_unstable() and friends [v2,31/32] mm/swap: swap_vma_readahead() do the pte_offset_map() [v2,32/32] perf/core: Allow pte_offset_map() to fail

Commit Message

Hugh Dickins June 9, 2023, 1:53 a.m. UTC

  In rare transient cases, not yet made possible, pte_offset_map() and
pte_offet_map_lock() may not find a page table: handle appropriately.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
This is a perf patch, not an mm patch, and it will want to go in through
the tip tree in due course; but keep it in this series for now, so that
it's not missed, and not submitted before mm review.

 kernel/events/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff mbox series

Patch

diff --git a/kernel/events/core.c b/kernel/events/core.c
index db016e418931..174be710f3b3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7490,6 +7490,7 @@  static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
 		return pud_leaf_size(pud);
 
 	pmdp = pmd_offset_lockless(pudp, pud, addr);
+again:
 	pmd = pmdp_get_lockless(pmdp);
 	if (!pmd_present(pmd))
 		return 0;
@@ -7498,6 +7499,9 @@  static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
 		return pmd_leaf_size(pmd);
 
 	ptep = pte_offset_map(&pmd, addr);
+	if (!ptep)
+		goto again;
+
 	pte = ptep_get_lockless(ptep);
 	if (pte_present(pte))
 		size = pte_leaf_size(pte);