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xen: take system_transition_mutex on suspend

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Xen's do_suspend() calls dpm_suspend_start() without taking required
system_transition_mutex. Since 12ffc3b151 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 <jgross@suse.com>
Fixes: 12ffc3b151 "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 <marmarek@invisiblethingslab.com>
Cc: stable@vger.kernel.org # v6.16+
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20250921162853.223116-1-marmarek@invisiblethingslab.com>
This commit is contained in:
Marek Marczykowski-Górecki
2025-09-21 18:28:47 +02:00
committed by Juergen Gross
parent f770c3d858
commit 9d52b0b41b
1 changed files with 10 additions and 1 deletions
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11
drivers/xen/manage.c
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@@ -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 @@ out_resume_end:
out_thaw:
thaw_processes();
out_unlock:
mutex_unlock(&system_transition_mutex);
out:
shutting_down = SHUTDOWN_INVALID;
}