PM: hibernate: Complain about memory map mismatches during resume

The system memory map can change over a hibernation-restore cycle due
to a defect in the platform firmware, and some of the page frames used
by the kernel before hibernation may not be available any more during
the subsequent restore which leads to the error below.

[  T357] PM: Image loading progress:   0%
[  T357] PM: Read 2681596 kbytes in 0.03 seconds (89386.53 MB/s)
[  T357] PM: Error -14 resuming
[  T357] PM: Failed to load hibernation image, recovering.
[  T357] PM: Basic memory bitmaps freed
[  T357] OOM killer enabled.
[  T357] Restarting tasks ... done.
[  T357] PM: resume from hibernation failed (-14)
[  T357] PM: Hibernation image not present or could not be loaded.

Add an error message to the unpack() function to allow problematic
page frames to be identified and the source of the problem to be
diagnosed more easily. This can save developers quite a bit of
debugging time.

Signed-off-by: Xueqin Luo <luoxueqin@kylinos.cn>
[ rjw: New subject, edited changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index c20ca5fb9adc875b7b0433345a8c30aec419d5a2..cd8b7b35f1e8bb9589b3d819f809b56a7a46daf1 100644 (file)
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -2259,10 +2259,14 @@ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
                if (unlikely(buf[j] == BM_END_OF_MAP))
                        break;
 
-               if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j]))
+               if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j])) {
                        memory_bm_set_bit(bm, buf[j]);
-               else
+               } else {
+                       if (!pfn_valid(buf[j]))
+                               pr_err(FW_BUG "Memory map mismatch at 0x%llx after hibernation\n",
+                                      (unsigned long long)PFN_PHYS(buf[j]));
                        return -EFAULT;
+               }
        }
 
        return 0;