From 9d52b0b41be5b932a0a929c10038f1bb04af4ca5 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marek=20Marczykowski-G=C3=B3recki?= Date: Sun, 21 Sep 2025 18:28:47 +0200 Subject: [PATCH] xen: take system_transition_mutex on suspend MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Xen's do_suspend() calls dpm_suspend_start() without taking required system_transition_mutex. Since 12ffc3b1513eb moved the pm_restrict_gfp_mask() call, not taking that mutex results in a WARN. Take the mutex in do_suspend(), and use mutex_trylock() to follow how enter_state() does this. Suggested-by: Jürgen Groß Fixes: 12ffc3b1513eb "PM: Restrict swap use to later in the suspend sequence" Link: https://lore.kernel.org/xen-devel/aKiBJeqsYx_4Top5@mail-itl/ Signed-off-by: Marek Marczykowski-Górecki Cc: stable@vger.kernel.org # v6.16+ Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Message-ID: <20250921162853.223116-1-marmarek@invisiblethingslab.com> --- drivers/xen/manage.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index 1f5a7a42fc32..e20c40a62e64 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -95,10 +96,16 @@ static void do_suspend(void) shutting_down = SHUTDOWN_SUSPEND; + if (!mutex_trylock(&system_transition_mutex)) + { + pr_err("%s: failed to take system_transition_mutex\n", __func__); + goto out; + } + err = freeze_processes(); if (err) { pr_err("%s: freeze processes failed %d\n", __func__, err); - goto out; + goto out_unlock; } err = freeze_kernel_threads(); @@ -155,6 +162,8 @@ out_resume_end: out_thaw: thaw_processes(); +out_unlock: + mutex_unlock(&system_transition_mutex); out: shutting_down = SHUTDOWN_INVALID; } -- 2.20.1