The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1a0aa991a6274161c95a844c58cfb801d681eb59 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Date: Tue, 12 May 2020 17:02:56 +0900 Subject: [PATCH] kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex In kprobe_optimizer() kick_kprobe_optimizer() is called without kprobe_mutex, but this can race with other caller which is protected by kprobe_mutex. To fix that, expand kprobe_mutex protected area to protect kick_kprobe_optimizer() call. Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2 Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing") Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "Gustavo A . R . Silva" <gustavoars@xxxxxxxxxx> Cc: Anders Roxell <anders.roxell@xxxxxxxxxx> Cc: "Naveen N . Rao" <naveen.n.rao@xxxxxxxxxxxxx> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx> Cc: David Miller <davem@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ziqian SUN <zsun@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> diff --git a/kernel/kprobes.c b/kernel/kprobes.c index ceb0e273bd69..0e185763578b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -592,11 +592,12 @@ static void kprobe_optimizer(struct work_struct *work) mutex_unlock(&module_mutex); mutex_unlock(&text_mutex); cpus_read_unlock(); - mutex_unlock(&kprobe_mutex); /* Step 5: Kick optimizer again if needed */ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) kick_kprobe_optimizer(); + + mutex_unlock(&kprobe_mutex); } /* Wait for completing optimization and unoptimization */
