The patch titled
Subject: mm/madvise: report SIGBUS as -EFAULT for MADV_POPULATE_(READ|WRITE)
has been removed from the -mm tree. Its filename was
mm-madvise-report-sigbus-as-efault-for-madv_populate_readwrite.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/madvise: report SIGBUS as -EFAULT for MADV_POPULATE_(READ|WRITE)
Doing some extended tests and polishing the man page update for
MADV_POPULATE_(READ|WRITE), I realized that we end up converting also
SIGBUS (via -EFAULT) to -EINVAL, making it look like yet another madvise()
user error.
We want to report only problematic mappings and permission problems that
the user could have know as -EINVAL.
Let's not convert -EFAULT arising due to SIGBUS (or SIGSEGV) to -EINVAL,
but instead indicate -EFAULT to user space. While we could also convert
it to -ENOMEM, using -EFAULT looks more helpful when user space might want
to troubleshoot what's going wrong: MADV_POPULATE_(READ|WRITE) is not part
of an final Linux release and we can still adjust the behavio= r.
Link: https://lkml.kernel.org/r/20210726154932.102880-1-david@xxxxxxxxxx
Fixes: 4ca9b3859dac ("mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables")
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rolf Eike Beer <eike-kernel@xxxxxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 7 +++++--
mm/madvise.c | 4 +++-
2 files changed, 8 insertions(+), 3 deletions(-)
--- a/mm/gup.c~mm-madvise-report-sigbus-as-efault-for-madv_populate_readwrite
+++ a/mm/gup.c
@@ -1558,9 +1558,12 @@ long faultin_vma_page_range(struct vm_ar
gup_flags |= FOLL_WRITE;
/*
- * See check_vma_flags(): Will return -EFAULT on incompatible mappings
- * or with insufficient permissions.
+ * We want to report -EINVAL instead of -EFAULT for any permission
+ * problems or incompatible mappings.
*/
+ if (check_vma_flags(vma, gup_flags))
+ return -EINVAL;
+
return __get_user_pages(mm, start, nr_pages, gup_flags,
NULL, NULL, locked);
}
--- a/mm/madvise.c~mm-madvise-report-sigbus-as-efault-for-madv_populate_readwrite
+++ a/mm/madvise.c
@@ -862,10 +862,12 @@ static long madvise_populate(struct vm_a
switch (pages) {
case -EINTR:
return -EINTR;
- case -EFAULT: /* Incompatible mappings / permissions. */
+ case -EINVAL: /* Incompatible mappings / permissions. */
return -EINVAL;
case -EHWPOISON:
return -EHWPOISON;
+ case -EFAULT: /* VM_FAULT_SIGBUS or VM_FAULT_SIGSEGV */
+ return -EFAULT;
default:
pr_warn_once("%s: unhandled return value: %ld\n",
__func__, pages);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
memory-hotplugrst-remove-locking-details-from-admin-guide.patch
memory-hotplugrst-complete-admin-guide-overhaul.patch
mm-memory_hotplug-use-unsigned-long-for-pfn-in-zone_for_pfn_range.patch
mm-memory_hotplug-remove-nid-parameter-from-arch_remove_memory.patch
mm-memory_hotplug-remove-nid-parameter-from-remove_memory-and-friends.patch
acpi-memhotplug-memory-resources-cannot-be-enabled-yet.patch
mm-track-present-early-pages-per-zone.patch
mm-memory_hotplug-introduce-auto-movable-online-policy.patch
drivers-base-memory-introduce-memory-groups-to-logically-group-memory-blocks.patch
mm-memory_hotplug-track-present-pages-in-memory-groups.patch
acpi-memhotplug-use-a-single-static-memory-group-for-a-single-memory-device.patch
dax-kmem-use-a-single-static-memory-group-for-a-single-probed-unit.patch
virtio-mem-use-a-single-dynamic-memory-group-for-a-single-virtio-mem-device.patch
mm-memory_hotplug-memory-group-aware-auto-movable-online-policy.patch
mm-memory_hotplug-improved-dynamic-memory-group-aware-auto-movable-online-policy.patch
