Commit 9d52b0b4 authored by Marek Marczykowski-Górecki's avatar Marek Marczykowski-Górecki Committed by Juergen Gross
Browse files

xen: take system_transition_mutex on suspend 



Xen's do_suspend() calls dpm_suspend_start() without taking required
system_transition_mutex. Since 12ffc3b1 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: default avatarJürgen Groß <jgross@suse.com>
Fixes: 12ffc3b1 "PM: Restrict swap use to later in the suspend sequence"
Link: https://lore.kernel.org/xen-devel/aKiBJeqsYx_4Top5@mail-itl/


Signed-off-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Cc: stable@vger.kernel.org # v6.16+
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Message-ID: <20250921162853.223116-1-marmarek@invisiblethingslab.com>
parent f770c3d8

drivers/xen/manage.c

+10 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/reboot.h>

#include <linux/sysrq.h>

#include <linux/stop_machine.h>

#include <linux/suspend.h>

#include <linux/freezer.h>

#include <linux/syscore_ops.h>

#include <linux/export.h>
@@ -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 @@ static void do_suspend(void) 


out_thaw:

	thaw_processes();

out_unlock:

	mutex_unlock(&system_transition_mutex);

out:

	shutting_down = SHUTDOWN_INVALID;

}