+ mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch added to -mm tree

* + mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch added to -mm tree
@ 2020-09-14  0:25 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2020-09-14  0:25 UTC (permalink / raw)
  To: mm-commits, lkp, aneesh.kumar


The patch titled
     Subject: mm/debug_vm_pgtable: avoid doing memory allocation with pgtable_t mapped.
has been added to the -mm tree.  Its filename is
     mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch

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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: mm/debug_vm_pgtable: avoid doing memory allocation with pgtable_t mapped.

With highmem, pte_alloc_map() keep the level4 page table mapped using
kmap_atomic().  Avoid doing new memory allocation with page table mapped
like above.

[    9.409233] BUG: sleeping function called from invalid context at mm/page_alloc.c:4822
[    9.410557] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
[    9.411932] no locks held by swapper/1.
[    9.412595] CPU: 0 PID: 1 Comm: swapper Not tainted 5.9.0-rc3-00323-gc50eb1ed654b5 #2
[    9.413824] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[    9.415207] Call Trace:
[    9.415651]  ? ___might_sleep.cold+0xa7/0xcc
[    9.416367]  ? __alloc_pages_nodemask+0x14c/0x5b0
[    9.417055]  ? swap_migration_tests+0x50/0x293
[    9.417704]  ? debug_vm_pgtable+0x4bc/0x708
[    9.418287]  ? swap_migration_tests+0x293/0x293
[    9.418911]  ? do_one_initcall+0x82/0x3cb
[    9.419465]  ? parse_args+0x1bd/0x280
[    9.419983]  ? rcu_read_lock_sched_held+0x36/0x60
[    9.420673]  ? trace_initcall_level+0x1f/0xf3
[    9.421279]  ? trace_initcall_level+0xbd/0xf3
[    9.421881]  ? do_basic_setup+0x9d/0xdd
[    9.422410]  ? do_basic_setup+0xc3/0xdd
[    9.422938]  ? kernel_init_freeable+0x72/0xa3
[    9.423539]  ? rest_init+0x134/0x134
[    9.424055]  ? kernel_init+0x5/0x12c
[    9.424574]  ? ret_from_fork+0x19/0x30

Link: https://lkml.kernel.org/r/20200913110327.645310-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/debug_vm_pgtable.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped
+++ a/mm/debug_vm_pgtable.c
@@ -994,7 +994,13 @@ static int __init debug_vm_pgtable(void)
 	p4dp = p4d_alloc(mm, pgdp, vaddr);
 	pudp = pud_alloc(mm, p4dp, vaddr);
 	pmdp = pmd_alloc(mm, pudp, vaddr);
-	ptep = pte_alloc_map(mm, pmdp, vaddr);
+	/*
+	 * Allocate pgtable_t
+	 */
+	if (pte_alloc(mm, pmdp)) {
+		pr_err("pgtable allocation failed\n");
+		return 1;
+	}
 
 	/*
 	 * Save all the page table page addresses as the page table
@@ -1048,8 +1054,7 @@ static int __init debug_vm_pgtable(void)
 	 * proper page table lock.
 	 */
 
-	ptl = pte_lockptr(mm, pmdp);
-	spin_lock(ptl);
+	ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
 	pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
 	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
 	pte_unmap_unlock(ptep, ptl);
_

Patches currently in -mm which might be from aneesh.kumar@linux.ibm.com are

powerpc-mm-add-debug_vm-warn-for-pmd_clear.patch
powerpc-mm-move-setting-pte-specific-flags-to-pfn_pte.patch
mm-debug_vm_pgtable-ppc64-avoid-setting-top-bits-in-radom-value.patch
mm-debug_vm_pgtables-hugevmap-use-the-arch-helper-to-identify-huge-vmap-support.patch
mm-debug_vm_pgtable-savedwrite-enable-savedwrite-test-with-config_numa_balancing.patch
mm-debug_vm_pgtable-thp-mark-the-pte-entry-huge-before-using-set_pmd-pud_at.patch
mm-debug_vm_pgtable-set_pte-pmd-pud-dont-use-set__at-to-update-an-existing-pte-entry.patch
mm-debug_vm_pgtable-locks-move-non-page-table-modifying-test-together.patch
mm-debug_vm_pgtable-locks-take-correct-page-table-lock.patch
mm-debug_vm_pgtable-thp-use-page-table-depost-withdraw-with-thp.patch
mm-debug_vm_pgtable-pmd_clear-dont-use-pmd-pud_clear-on-pte-entries.patch
mm-debug_vm_pgtable-hugetlb-disable-hugetlb-test-on-ppc64.patch
mm-debug_vm_pgtable-avoid-none-pte-in-pte_clear_test.patch
mm-debug_vm_pgtable-avoid-doing-memory-allocation-with-pgtable_t-mapped.patch


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