From 2780505ec2b42c07853b34640bc63279ac2bb53b Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Sun, 6 Jul 2025 12:32:03 -0700 Subject: [PATCH] samples/damon/prcl: fix boot time enable crash If 'enable' parameter of the 'prcl' DAMON sample module is set at boot time via the kernel command line, memory allocation is tried before the slab is initialized. As a result kernel NULL pointer dereference BUG can happen. Fix it by checking the initialization status. Link: https://lkml.kernel.org/r/20250706193207.39810-3-sj@kernel.org Fixes: 2aca254620a8 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- samples/damon/prcl.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/samples/damon/prcl.c b/samples/damon/prcl.c index 5597e6a08ab22..a9d7629d70f0a 100644 --- a/samples/damon/prcl.c +++ b/samples/damon/prcl.c @@ -109,6 +109,8 @@ static void damon_sample_prcl_stop(void) put_pid(target_pidp); } +static bool init_called; + static int damon_sample_prcl_enable_store( const char *val, const struct kernel_param *kp) { @@ -134,6 +136,14 @@ static int damon_sample_prcl_enable_store( static int __init damon_sample_prcl_init(void) { + int err = 0; + + init_called = true; + if (enable) { + err = damon_sample_prcl_start(); + if (err) + enable = false; + } return 0; } -- 2.47.2