From: Keith Busch kbusch@kernel.org
[ Upstream commit c89a529e823d51dd23c7ec0c047c7a454a428541 ]
Convert the max size to bytes to match the units of the divisor that calculates the worst-case number of PRP entries.
The result is used to determine how many PRP Lists are required. The code was previously rounding this to 1 list, but we can require 2 in the worst case. In that scenario, the driver would corrupt memory beyond the size provided by the mempool.
While unlikely to occur (you'd need a 4MB in exactly 127 phys segments on a queue that doesn't support SGLs), this memory corruption has been observed by kfence.
Cc: Jens Axboe axboe@kernel.dk Fixes: 943e942e6266f ("nvme-pci: limit max IO size and segments to avoid high order allocations") Signed-off-by: Keith Busch kbusch@kernel.org Reviewed-by: Jens Axboe axboe@kernel.dk Reviewed-by: Kanchan Joshi joshi.k@samsung.com Reviewed-by: Chaitanya Kulkarni kch@nvidia.com Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 4ed8a14e2803..3116a0e2ec27 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -378,8 +378,8 @@ static bool nvme_dbbuf_update_and_check_event(u16 value, __le32 *dbbuf_db, */ static int nvme_pci_npages_prp(void) { - unsigned nprps = DIV_ROUND_UP(NVME_MAX_KB_SZ + NVME_CTRL_PAGE_SIZE, - NVME_CTRL_PAGE_SIZE); + unsigned max_bytes = (NVME_MAX_KB_SZ * 1024) + NVME_CTRL_PAGE_SIZE; + unsigned nprps = DIV_ROUND_UP(max_bytes, NVME_CTRL_PAGE_SIZE); return DIV_ROUND_UP(8 * nprps, PAGE_SIZE - 8); }