After commit f7d5bcd35d ("selftests: kselftest: Mark functions that
unconditionally call exit() as __noreturn"), ksft_exit_...() functions
are marked as __noreturn, which means the return type should not be
'int' but 'void' because they are not returning anything (and never were
since exit() has always been called).
To facilitate updating the return type of these functions, remove
'return' before the calls to ksft_exit_...(), as __noreturn prevents the
compiler from warning that a caller of the ksft_exit functions does not
return a value because the program will terminate upon calling these
functions.
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The #endif is the wrong side of a } causing a build failure when
__NR_userfaultfd is not defined. Fix this by moving the #end to enclose
the }
Link: https://lkml.kernel.org/r/20230712134648.456349-1-colin.i.king@gmail.com
Fixes: 9eac40fc0c ("selftests/mm: mkdirty: test behavior of (pte|pmd)_mkdirty on VMAs without write permissions")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's add some tests that trigger (pte|pmd)_mkdirty on VMAs without write
permissions. If an architecture implementation is wrong, we might
accidentally set the PTE/PMD writable and allow for write access in a VMA
without write permissions.
The tests include reproducers for the two issues recently discovered
and worked-around in core-MM for now:
(1) commit 624a2c94f5 ("Partly revert "mm/thp: carry over dirty
bit when thp splits on pmd"")
(2) commit 96a9c287e2 ("mm/migrate: fix wrongly apply write bit
after mkdirty on sparc64")
In addition, some other tests that reveal further issues.
All tests pass under x86_64:
./mkdirty
# [INFO] detected THP size: 2048 KiB
TAP version 13
1..6
# [INFO] PTRACE write access
ok 1 SIGSEGV generated, page not modified
# [INFO] PTRACE write access to THP
ok 2 SIGSEGV generated, page not modified
# [INFO] Page migration
ok 3 SIGSEGV generated, page not modified
# [INFO] Page migration of THP
ok 4 SIGSEGV generated, page not modified
# [INFO] PTE-mapping a THP
ok 5 SIGSEGV generated, page not modified
# [INFO] UFFDIO_COPY
ok 6 SIGSEGV generated, page not modified
# Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0
But some fail on sparc64:
./mkdirty
# [INFO] detected THP size: 8192 KiB
TAP version 13
1..6
# [INFO] PTRACE write access
not ok 1 SIGSEGV generated, page not modified
# [INFO] PTRACE write access to THP
not ok 2 SIGSEGV generated, page not modified
# [INFO] Page migration
ok 3 SIGSEGV generated, page not modified
# [INFO] Page migration of THP
ok 4 SIGSEGV generated, page not modified
# [INFO] PTE-mapping a THP
ok 5 SIGSEGV generated, page not modified
# [INFO] UFFDIO_COPY
not ok 6 SIGSEGV generated, page not modified
Bail out! 3 out of 6 tests failed
# Totals: pass:3 fail:3 xfail:0 xpass:0 skip:0 error:0
Reverting both above commits makes all tests fail on sparc64:
./mkdirty
# [INFO] detected THP size: 8192 KiB
TAP version 13
1..6
# [INFO] PTRACE write access
not ok 1 SIGSEGV generated, page not modified
# [INFO] PTRACE write access to THP
not ok 2 SIGSEGV generated, page not modified
# [INFO] Page migration
not ok 3 SIGSEGV generated, page not modified
# [INFO] Page migration of THP
not ok 4 SIGSEGV generated, page not modified
# [INFO] PTE-mapping a THP
not ok 5 SIGSEGV generated, page not modified
# [INFO] UFFDIO_COPY
not ok 6 SIGSEGV generated, page not modified
Bail out! 6 out of 6 tests failed
# Totals: pass:0 fail:6 xfail:0 xpass:0 skip:0 error:0
The tests are useful to detect other problematic archs, to verify new
arch fixes, and to stop such issues from reappearing in the future.
For now, we don't add any hugetlb tests.
Link: https://lkml.kernel.org/r/20230411142512.438404-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
