is_madv_discard did its check wrong. MADV_ flags are not bitwise, they're normal sequential numbers. So, for instance: behavior & (/* ... */ | MADV_REMOVE)

tagged both MADV_REMOVE and MADV_RANDOM (bit 0 set) as discard operations. This is obviously incorrect, so use a switch statement instead.

Cc: stable@vger.kernel.org Fixes: 8be7258aad44 ("mseal: add mseal syscall") Signed-off-by: Pedro Falcato pedro.falcato@gmail.com --- mm/mseal.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/mm/mseal.c b/mm/mseal.c index bf783bba8ed..15bba28acc0 100644 --- a/mm/mseal.c +++ b/mm/mseal.c @@ -40,9 +40,17 @@ static bool can_modify_vma(struct vm_area_struct *vma)

static bool is_madv_discard(int behavior) { - return behavior & - (MADV_FREE | MADV_DONTNEED | MADV_DONTNEED_LOCKED | - MADV_REMOVE | MADV_DONTFORK | MADV_WIPEONFORK); + switch (behavior) { + case MADV_FREE: + case MADV_DONTNEED: + case MADV_DONTNEED_LOCKED: + case MADV_REMOVE: + case MADV_DONTFORK: + case MADV_WIPEONFORK: + return true; + } + + return false; }

static bool is_ro_anon(struct vm_area_struct *vma)