In the quest to remove all stack VLA usage from the kernel[1], this switches to using a kmalloc-allocated buffer instead of stack space. This should be fine since the existing routine is allocating memory too.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qpxydaacu1rq...@mail.gmail.com Cc: David Daney <[email protected]> Cc: Jan Glauber <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Mauro Carvalho Chehab <[email protected]> Cc: [email protected] Signed-off-by: Kees Cook <[email protected]> --- drivers/edac/thunderx_edac.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c index 4803c6468bab..c009d94f40c5 100644 --- a/drivers/edac/thunderx_edac.c +++ b/drivers/edac/thunderx_edac.c @@ -408,26 +408,29 @@ static ssize_t thunderx_lmc_inject_ecc_write(struct file *file, size_t count, loff_t *ppos) { struct thunderx_lmc *lmc = file->private_data; - unsigned int cline_size = cache_line_size(); - - u8 tmp[cline_size]; + u8 *tmp; void __iomem *addr; unsigned int offs, timeout = 100000; atomic_set(&lmc->ecc_int, 0); lmc->mem = alloc_pages_node(lmc->node, GFP_KERNEL, 0); - if (!lmc->mem) return -ENOMEM; + tmp = kmalloc(cline_size, GFP_KERNEL); + if (!tmp) { + __free_pages(lmc->mem, 0); + return -ENOMEM; + } + addr = page_address(lmc->mem); while (!atomic_read(&lmc->ecc_int) && timeout--) { stop_machine(inject_ecc_fn, lmc, NULL); - for (offs = 0; offs < PAGE_SIZE; offs += sizeof(tmp)) { + for (offs = 0; offs < PAGE_SIZE; offs += cline_size) { /* * Do a load from the previously rigged location * This should generate an error interrupt. @@ -437,6 +440,7 @@ static ssize_t thunderx_lmc_inject_ecc_write(struct file *file, } } + kfree(tmp); __free_pages(lmc->mem, 0); return count; -- 2.17.1 -- Kees Cook Pixel Security
