When sme_alloc() is called with existing storage and we are not flushing we will always allocate new storage, both leaking the existing storage and corrupting the state. Fix this by separating the checks for flushing and for existing storage as we do for SVE.

Callers that reallocate (eg, due to changing the vector length) should call sme_free() themselves.

Fixes: 5d0a8d2fba50 (arm64/ptrace: Ensure that SME is set up for target when writing SSVE state) Signed-off-by: Mark Brown broonie@kernel.org Cc: stable@vger.kernel.org --- arch/arm64/kernel/fpsimd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 1559c706d32d..7363f2eb98e8 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1245,8 +1245,10 @@ void fpsimd_release_task(struct task_struct *dead_task) */ void sme_alloc(struct task_struct *task, bool flush) { - if (task->thread.sme_state && flush) { - memset(task->thread.sme_state, 0, sme_state_size(task)); + if (task->thread.sme_state) { + if (flush) + memset(task->thread.sme_state, 0, + sme_state_size(task)); return; }

--- base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a change-id: 20240112-arm64-sme-flush-09bdc40bb4fc

Best regards,