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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-11-14 23:26:58 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-11-14 23:26:58 +0100
commit6a0c7cd33075f6b7f1d80145bb19812beb3fc5c9 (patch)
tree1c77c05c8d41003216262585a82155fcb448fa41 /kernel
parent5e01dc7b26d9f24f39abace5da98ccbd6a5ceb52 (diff)
PM / Hibernate: Do not crash kernel in free_basic_memory_bitmaps()
I have received a report about the BUG_ON() in free_basic_memory_bitmaps() triggering mysteriously during an aborted s2disk hibernation attempt. The only way I can explain that is that /dev/snapshot was first opened for writing (resume mode), then closed and then opened again for reading and closed again without freezing tasks. In that case the first invocation of snapshot_open() would set the free_bitmaps flag in snapshot_state, which is a static variable. That flag wouldn't be cleared later and the second invocation of snapshot_open() would just leave it like that, so the subsequent snapshot_release() would see data->frozen set and free_basic_memory_bitmaps() would be called unnecessarily. To prevent that from happening clear data->free_bitmaps in snapshot_open() when the file is being opened for reading (hibernate mode). In addition to that, replace the BUG_ON() in free_basic_memory_bitmaps() with a WARN_ON() as the kernel can continue just fine if the condition checked by that macro occurs. Fixes: aab172891542 (PM / hibernate: Fix user space driven resume regression) Reported-by: Oliver Lorenz <olli@olorenz.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/snapshot.c3
-rw-r--r--kernel/power/user.c1
2 files changed, 3 insertions, 1 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 98c3b34a4cf..ac2d1f69490 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -792,7 +792,8 @@ void free_basic_memory_bitmaps(void)
{
struct memory_bitmap *bm1, *bm2;
- BUG_ON(!(forbidden_pages_map && free_pages_map));
+ if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
+ return;
bm1 = forbidden_pages_map;
bm2 = free_pages_map;
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 957f06164ad..ffc931c384a 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -70,6 +70,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
data->swap = swsusp_resume_device ?
swap_type_of(swsusp_resume_device, 0, NULL) : -1;
data->mode = O_RDONLY;
+ data->free_bitmaps = false;
error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
if (error)
pm_notifier_call_chain(PM_POST_HIBERNATION);