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| author | David Hildenbrand <david@redhat.com> | 2021-08-13 16:54:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-08-13 14:09:31 -1000 |
| commit | eb2faa513c246ed47ae34a205928ab663bc5a18f (patch) | |
| tree | 0cd7f02657f6af9e20faf9c834a9c37eb2c8291b /mm/madvise.c | |
| parent | a7f1d48585b34730765dcda09ead6edc4ac16a5c (diff) | |
| download | lwn-eb2faa513c246ed47ae34a205928ab663bc5a18f.tar.gz lwn-eb2faa513c246ed47ae34a205928ab663bc5a18f.zip | |
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 behavior.
Link: https://lkml.kernel.org/r/20210726154932.102880-1-david@redhat.com
Fixes: 4ca9b3859dac ("mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 6d3d348b17f4..5c065bc8b5f6 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -862,10 +862,12 @@ static long madvise_populate(struct vm_area_struct *vma, 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); |