The patch titled Subject: mm/zswap: fix potential uninitialized pointer read on tmp has been added to the -mm tree. Its filename is mm-zswap-add-the-flag-can_sleep_mapped-fix-3.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-zswap-add-the-flag-can_sleep_mapped-fix-3.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-zswap-add-the-flag-can_sleep_mapped-fix-3.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Colin Ian King <colin.king@xxxxxxxxxxxxx> Subject: mm/zswap: fix potential uninitialized pointer read on tmp In the case where zpool_can_sleep_mapped(pool) returns 0 then tmp is not allocated and tmp is then an uninitialized pointer. Later if entry is null, tmp is freed, hence free'ing an uninitialized pointer. Fix this by ensuring tmp is initialized to NULL. Link: https://lkml.kernel.org/r/20210128141728.639030-1-colin.king@xxxxxxxxxxxxx Addresses-Coverity: ("Uninitialized pointer read") Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> Cc: Seth Jennings <sjenning@xxxxxxxxxx> Cc: Dan Streetman <ddstreet@xxxxxxxx> Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx> Cc: Tian Tao <tiantao6@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/zswap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/zswap.c~mm-zswap-add-the-flag-can_sleep_mapped-fix-3 +++ a/mm/zswap.c @@ -935,7 +935,7 @@ static int zswap_writeback_entry(struct struct scatterlist input, output; struct crypto_acomp_ctx *acomp_ctx; - u8 *src, *tmp; + u8 *src, *tmp = NULL; unsigned int dlen; int ret; struct writeback_control wbc = { _ Patches currently in -mm which might be from colin.king@xxxxxxxxxxxxx are mm-zswap-add-the-flag-can_sleep_mapped-fix-3.patch