Messages in this thread | | | From | Shuah Khan <> | Subject | [PATCH v3 0/2] power_supply: Fix Oops from NULL pointer dereference from wakeup_source_activate | Date | Fri, 22 Nov 2013 10:54:27 -0700 |
| |
power_supply_register() calls device_init_wakeup() to register a wakeup source before initializing dev_name. As a result, device_wakeup_enable() end up registering wakeup source with a null name when wakeup_source_register() gets called with dev_name(dev) which is null at the time.
device_wakeup_enable() uses dev_name(dev) as the wakeup source name. When it gets called with a device with its name not yet set, ws structure with ws->name = NULL gets created.
When kernel is booted with wakeup_source_activate enabled, it will panic when the trace point code tries to dereference ws->name. Registering a a wakeup source without a name should be possible.
This patch series fixes power_supply_register() to initialize the device name prior to calling device_init_wakeup() and fixes tracing infrastructure to be more robust in handling null strings in __assign_string() and __string(). With this change null string is handled gracefully and replacing it with "(null)" when trace is generated.
These two patches are not dependent, I left them as a series since the original discussion started the fixes grouped in a series.
power_supply patch - no changes since series patch v1, other than including Acked-by from Greg and Anton. Also added stable tag.
Second patch now is the fix to tracepoint infrastructure routines __assign_string() and __string(). This will address the problem at the tracing infrastructure level which is better than fixing individual tracepoint code.
These patches can be applied independently with no ill effects. I included the trace for the wakeup_source_activate trace output in the change logs for both patches.
Shuah Khan (2): power_supply: Fix Oops from NULL pointer dereference from wakeup_source_activate tracing: Fix Oops from NULL pointer dereference from __assign_str
drivers/power/power_supply_core.c | 12 ++++++------ include/trace/ftrace.h | 7 +++++-- 2 files changed, 11 insertions(+), 8 deletions(-)
-- 1.8.3.2
| |