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authorTodd E Brandt <todd.e.brandt@linux.intel.com>2016-03-02 16:05:29 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-03-03 02:28:28 +0100
commit92f9e179a702a6adbc11e2fedc76ecd6ffc9e3f7 (patch)
tree72ee540a52c68f71d4cf7b13bc8fa188bee8759f
parentfc77dbd34c5c99bce46d40a2491937c3bcbd10af (diff)
downloadlwn-92f9e179a702a6adbc11e2fedc76ecd6ffc9e3f7.tar.gz
lwn-92f9e179a702a6adbc11e2fedc76ecd6ffc9e3f7.zip
PM / sleep / x86: Fix crash on graph trace through x86 suspend
Pause/unpause graph tracing around do_suspend_lowlevel as it has inconsistent call/return info after it jumps to the wakeup vector. The graph trace buffer will otherwise become misaligned and may eventually crash and hang on suspend. To reproduce the issue and test the fix: Run a function_graph trace over suspend/resume and set the graph function to suspend_devices_and_enter. This consistently hangs the system without this fix. Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com> Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--arch/x86/kernel/acpi/sleep.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index d1daead5fcdd..adb3eaf8fe2a 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -16,6 +16,7 @@
#include <asm/cacheflush.h>
#include <asm/realmode.h>
+#include <linux/ftrace.h>
#include "../../realmode/rm/wakeup.h"
#include "sleep.h"
@@ -107,7 +108,13 @@ int x86_acpi_suspend_lowlevel(void)
saved_magic = 0x123456789abcdef0L;
#endif /* CONFIG_64BIT */
+ /*
+ * Pause/unpause graph tracing around do_suspend_lowlevel as it has
+ * inconsistent call/return info after it jumps to the wakeup vector.
+ */
+ pause_graph_tracing();
do_suspend_lowlevel();
+ unpause_graph_tracing();
return 0;
}