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| author |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-11-14 23:26:58 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-11-14 23:26:58 +0100 |
| commit | 6a0c7cd33075f6b7f1d80145bb19812beb3fc5c9 (patch) | |
| tree | 1c77c05c8d41003216262585a82155fcb448fa41 /kernel | |
| parent | Linux 3.12 (diff) | |
| download | linux-dev-6a0c7cd33075f6b7f1d80145bb19812beb3fc5c9.tar.xz linux-dev-6a0c7cd33075f6b7f1d80145bb19812beb3fc5c9.zip | |
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.c | 3 | ||||
| -rw-r--r-- | kernel/power/user.c | 1 |
2 files changed, 3 insertions, 1 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 98c3b34a4cff..ac2d1f69490f 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 957f06164ad1..ffc931c384ac 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); |