linux/arch/powerpc
Benjamin Herrenschmidt f4ac7b5eb7 [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 <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-18 15:37:16 +10:00
..
boot
configs
kernel [POWERPC] Fix device-tree locking vs. interrupts 2008-04-18 15:37:16 +10:00
lib
math-emu
mm [POWERPC] Remove unused __max_memory variable 2008-04-18 15:37:11 +10:00
oprofile
platforms [POWERPC] Simplify xics direct/lpar irq_host setup 2008-04-18 15:36:11 +10:00
sysdev
xmon
.gitignore
Kconfig
Kconfig.debug
Makefile