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Message-Id: <e2279c339fcf919cffa4802b4e32974dc8950513.1693972725.git.yu.c.chen@intel.com>
Date: Wed, 6 Sep 2023 12:18:52 +0800
From: Chen Yu <yu.c.chen@...el.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>,
Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Chenzhou Feng <chenzhoux.feng@...el.com>,
Pengfei Xu <pengfei.xu@...el.com>,
Chen Yu <yu.c.chen@...el.com>,
syzbot+38d04642cea49f3a3d2e@...kaller.appspotmail.com
Subject: [PATCH v2 2/2] PM: hibernate: Fix the exclusive get block device in test_resume mode
commit 5904de0d735b ("PM: hibernate: Do not get block device exclusively
in test_resume mode") fixes a hibernation issue under test_resume mode.
That commit is supposed to open the block device in non-exclusive mode
when in test_resume. However the code did the opposite, which is against
its description.
In summary, the swap device is only opened exclusively by swsusp_check()
with its corresponding *close(), and must be in non test_resume mode.
This is to avoid the race condition that different processes scribble the
device at the same time. All the other cases should use non-exclusive mode.
Fix it by really disabling exclusive mode under test_resume.
Fixes: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode")
Reported-by: syzbot+38d04642cea49f3a3d2e@...kaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/000000000000761f5f0603324129@google.com/
Reported-by: Pengfei Xu <pengfei.xu@...el.com>
Signed-off-by: Chen Yu <yu.c.chen@...el.com>
---
kernel/power/hibernate.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 2b4a946a6ff5..8d35b9f9aaa3 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -786,9 +786,9 @@ int hibernate(void)
unlock_device_hotplug();
if (snapshot_test) {
pm_pr_dbg("Checking hibernation image\n");
- error = swsusp_check(snapshot_test);
+ error = swsusp_check(false);
if (!error)
- error = load_image_and_restore(snapshot_test);
+ error = load_image_and_restore(false);
}
thaw_processes();
@@ -945,14 +945,14 @@ static int software_resume(void)
pm_pr_dbg("Looking for hibernation image.\n");
mutex_lock(&system_transition_mutex);
- error = swsusp_check(false);
+ error = swsusp_check(true);
if (error)
goto Unlock;
/* The snapshot device should not be opened while we're running */
if (!hibernate_acquire()) {
error = -EBUSY;
- swsusp_close(false);
+ swsusp_close(true);
goto Unlock;
}
@@ -973,7 +973,7 @@ static int software_resume(void)
goto Close_Finish;
}
- error = load_image_and_restore(false);
+ error = load_image_and_restore(true);
thaw_processes();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);
@@ -987,7 +987,7 @@ static int software_resume(void)
pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
return error;
Close_Finish:
- swsusp_close(false);
+ swsusp_close(true);
goto Finish;
}
--
2.25.1
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