From b7577fe4c47a31ca7c99714c53244a44af03cdfe Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 22 Jun 2026 16:31:24 +0200 Subject: [PATCH] s390/diag: Add missing array_index_nospec() call to memtop_get_page_count() 'level' is user space controlled and used to read from an array. Add the missing array_index_nospec() call to prevent speculative execution. Cc: stable@vger.kernel.org Fixes: 0d30871739ab ("s390/diag: Add memory topology information via diag310") Signed-off-by: Heiko Carstens Reviewed-by: Mete Durlu Signed-off-by: Vasily Gorbik --- arch/s390/kernel/diag/diag310.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/s390/kernel/diag/diag310.c b/arch/s390/kernel/diag/diag310.c index f411562aa7f6..c68ec9d28513 100644 --- a/arch/s390/kernel/diag/diag310.c +++ b/arch/s390/kernel/diag/diag310.c @@ -190,17 +190,18 @@ static int memtop_get_stride_len(unsigned long *res) static int memtop_get_page_count(unsigned long *res, unsigned long level) { static unsigned long memtop_pages[DIAG310_LEVELMAX]; - unsigned long pages; + unsigned long pages, idx; int rc; if (level > DIAG310_LEVELMAX || level < DIAG310_LEVELMIN) return -EINVAL; - pages = READ_ONCE(memtop_pages[level - 1]); + idx = array_index_nospec(level - 1, ARRAY_SIZE(memtop_pages)); + pages = READ_ONCE(memtop_pages[idx]); if (!pages) { rc = diag310_get_memtop_size(&pages, level); if (rc) return rc; - WRITE_ONCE(memtop_pages[level - 1], pages); + WRITE_ONCE(memtop_pages[idx], pages); } *res = pages; return 0; -- 2.47.3