This is a note to let you know that I've just added the patch titled mmc: mmc_test: Fix NULL dereference on allocation failure to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mmc-mmc_test-fix-null-dereference-on-allocation-fail.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 881206e55febff0a076509e36ab69424a7682a2b Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Tue Aug 20 11:44:08 2024 +0300 mmc: mmc_test: Fix NULL dereference on allocation failure [ Upstream commit a1e627af32ed60713941cbfc8075d44cad07f6dd ] If the "test->highmem = alloc_pages()" allocation fails then calling __free_pages(test->highmem) will result in a NULL dereference. Also change the error code to -ENOMEM instead of returning success. Fixes: 2661081f5ab9 ("mmc_test: highmem tests") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Link: https://lore.kernel.org/r/8c90be28-67b4-4b0d-a105-034dc72a0b31@stanley.mountain Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/mmc/core/mmc_test.c b/drivers/mmc/core/mmc_test.c index ef18daeaa4cc6..164b4e43050e7 100644 --- a/drivers/mmc/core/mmc_test.c +++ b/drivers/mmc/core/mmc_test.c @@ -3101,13 +3101,13 @@ static ssize_t mtf_test_write(struct file *file, const char __user *buf, test->buffer = kzalloc(BUFFER_SIZE, GFP_KERNEL); #ifdef CONFIG_HIGHMEM test->highmem = alloc_pages(GFP_KERNEL | __GFP_HIGHMEM, BUFFER_ORDER); + if (!test->highmem) { + count = -ENOMEM; + goto free_test_buffer; + } #endif -#ifdef CONFIG_HIGHMEM - if (test->buffer && test->highmem) { -#else if (test->buffer) { -#endif mutex_lock(&mmc_test_lock); mmc_test_run(test, testcase); mutex_unlock(&mmc_test_lock); @@ -3115,6 +3115,7 @@ static ssize_t mtf_test_write(struct file *file, const char __user *buf, #ifdef CONFIG_HIGHMEM __free_pages(test->highmem, BUFFER_ORDER); +free_test_buffer: #endif kfree(test->buffer); kfree(test);