986c99cf59764060993eb60 parent f13f4ca8036516ca1b99a41f95f7dea7e4dce104 author Benjamin Herrenschmidt 1207725696 +1000 committer Paul Mackerras 1208497036 +1000 [POWERPC] Fix device-tree locking vs. interrupts Lockdep found out that we can occasionally take the device-tree lock for reading from softirq time (from rtas_token called by the rtas real time clock code called by the NTP code), while we take it occasionally for writing without masking interrupts. The combination of those two can thus deadlock. While some of those cases of interrupt read lock could be fixed (such as caching the RTAS tokens) I figured that taking the lock for writing is so rare (device-tree modification) that we may as well penalize that case and allow reading from interrupts. Thus, this turns all the writers to take the lock with irqs masked to avoid the situation. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras ±cè‘.x