This is a note to let you know that I've just added the patch titled tipc: fix using smp_processor_id() in preemptible to the 5.8-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: tipc-fix-using-smp_processor_id-in-preemptible.patch and it can be found in the queue-5.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Fri Sep 11 09:06:45 AM CEST 2020 From: Tuong Lien <tuong.t.lien@xxxxxxxxxxxxxx> Date: Sun, 30 Aug 2020 02:37:55 +0700 Subject: tipc: fix using smp_processor_id() in preemptible From: Tuong Lien <tuong.t.lien@xxxxxxxxxxxxxx> [ Upstream commit bb8872a1e6bc911869a729240781076ed950764b ] The 'this_cpu_ptr()' is used to obtain the AEAD key' TFM on the current CPU for encryption, however the execution can be preemptible since it's actually user-space context, so the 'using smp_processor_id() in preemptible' has been observed. We fix the issue by using the 'get/put_cpu_ptr()' API which consists of a 'preempt_disable()' instead. Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication") Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx> Signed-off-by: Tuong Lien <tuong.t.lien@xxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tipc/crypto.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/net/tipc/crypto.c +++ b/net/tipc/crypto.c @@ -326,7 +326,8 @@ static void tipc_aead_free(struct rcu_he if (aead->cloned) { tipc_aead_put(aead->cloned); } else { - head = *this_cpu_ptr(aead->tfm_entry); + head = *get_cpu_ptr(aead->tfm_entry); + put_cpu_ptr(aead->tfm_entry); list_for_each_entry_safe(tfm_entry, tmp, &head->list, list) { crypto_free_aead(tfm_entry->tfm); list_del(&tfm_entry->list); @@ -399,10 +400,15 @@ static void tipc_aead_users_set(struct t */ static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead) { - struct tipc_tfm **tfm_entry = this_cpu_ptr(aead->tfm_entry); + struct tipc_tfm **tfm_entry; + struct crypto_aead *tfm; + tfm_entry = get_cpu_ptr(aead->tfm_entry); *tfm_entry = list_next_entry(*tfm_entry, list); - return (*tfm_entry)->tfm; + tfm = (*tfm_entry)->tfm; + put_cpu_ptr(tfm_entry); + + return tfm; } /** Patches currently in stable-queue which might be from tuong.t.lien@xxxxxxxxxxxxxx are queue-5.8/tipc-fix-using-smp_processor_id-in-preemptible.patch