Hi adding Todd to cc On Thu, 15 Mar 2012, Nishanth Menon wrote: > clk_disable_unused is invoked when CONFIG_OMAP_RESET_CLOCKS=y. > Since clk_disable_unused is called as lateinitcall, there can > be more than a few workqueues executing off secondary CPU(s). > The current code does the following: > a) checks if clk is unused > b) holds lock > c) disables clk > d) unlocks > > Between (a) and (b) being executed on CPU0, It is possible to > have a driver executing on CPU1 which could do a get_sync->clk_get > (and increase the use_count) of the clock which was just about > to be disabled by clk_disable_unused. > > We ensure instead that the entire list traversal is protected by > the lock allowing for parent child clock traversal which could be > potentially be done by runtime operations to be safe as well. > > Reported-by: Todd Poynor <toddpoynor@xxxxxxxxxx> > Signed-off-by: Nishanth Menon <nm@xxxxxx> Thanks, I'll queue this for v3.4-rc1. In the medium term, we should get rid of CONFIG_OMAP_RESET_CLOCKS, at least for the OMAP2+ chips, and just do this by default. But this will need to wait until all of the OMAP2+ devices and drivers have been converted to use hwmod. Patches to that end are also gladly accepted :-) In 3.5 we should be in pretty good shape for OMAP4, but OMAP2/3 will still need some work. - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
