Re: [PATCH 3/3] kernel/hung_task convert hung_task_panic boot parameter to sysctl
From: Kees Cook <hidden>
Date: 2020-03-30 17:43:30
Also in:
linux-mm, lkml
On Mon, Mar 30, 2020 at 01:55:35PM +0200, Vlastimil Babka wrote:
We can now handle sysctl parameters on kernel command line and have infrastructure to convert legacy command line options that duplicate sysctl to become a sysctl alias. This patch converts the hung_task_panic parameter. Note that the sysctl handler is more strict and allows only 0 and 1, while the legacy parameter allowed any non-zero value. But there is little reason anyone would not be using 1. Signed-off-by: Vlastimil Babka <redacted>
I'll let others double-check, but I think this change should be okay. If not, we can adjust the sysctl handler to accept an arbitrary int. Reviewed-by: Kees Cook <redacted> -Kees
quoted hunk ↗ jump to hunk
--- Documentation/admin-guide/kernel-parameters.txt | 2 +- fs/proc/proc_sysctl.c | 1 + kernel/hung_task.c | 10 ---------- 3 files changed, 2 insertions(+), 11 deletions(-)diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 81ff626fc700..e0b8840404a1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt@@ -1457,7 +1457,7 @@ [KNL] Should the hung task detector generate panics. Format: <integer> - A nonzero value instructs the kernel to panic when a + A value of 1 instructs the kernel to panic when a hung task is detected. The default value is controlled by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value selected by this boot parameter candiff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 97eb0b552bf8..77b1b844b02b 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c@@ -1743,6 +1743,7 @@ struct sysctl_alias { */ static const struct sysctl_alias sysctl_aliases[] = { {"numa_zonelist_order", "vm.numa_zonelist_order" }, + {"hung_task_panic", "kernel.hung_task_panic" }, { } };diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 14a625c16cb3..b22b5eeab3cb 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c@@ -63,16 +63,6 @@ static struct task_struct *watchdog_task; unsigned int __read_mostly sysctl_hung_task_panic = CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE; -static int __init hung_task_panic_setup(char *str) -{ - int rc = kstrtouint(str, 0, &sysctl_hung_task_panic); - - if (rc) - return rc; - return 1; -} -__setup("hung_task_panic=", hung_task_panic_setup); - static int hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr) {-- 2.25.1
-- Kees Cook