Dear Guenter Roeck, > On Wed, Aug 01, 2012 at 02:28:40PM +0800, Shawn Guo wrote: > > On Tue, Jul 31, 2012 at 10:42:28PM -0700, Guenter Roeck wrote: > > > On Wed, Aug 01, 2012 at 01:58:56PM +0800, Shawn Guo wrote: > > > > On Tue, Jul 31, 2012 at 10:29:47PM -0700, Guenter Roeck wrote: > > > > > Anyone up for writing some patches ? If not, I'll do it. > > > > > > > > Go ahead. > > > > > > Ok, will do. It isn't that simple, actually, since at least some of the > > > drivers also call spi_master_get(), and thus need two calls to > > > spi_master_put() (or a call to spi_master_put and a call to kfree). > > > > Hmm, are you saying that there must be a spi_master_put call matching > > spi_alloc_master? I think we only need to have spi_master_get and > > spi_master_put matched. > > Yes, I think that may be so. Of course, I may be wrong, but ultimately that > is what almost all drivers do in the probe error path. Some of the drivers > do it in the remove path as well, though many don't. I suspect that all > drivers using spi_alloc_master() which do not call spi_master_put() in the > remove function may have a memory leak.
CCing Mark. > Someone who knows the spi infrastructure better than I should have a closer > look, though. The question is really quite simple: For example, in > spi-atmel.c, how is the allocated master freed in the _remove function ? > If it doesn't need the call to spi_master_put(), why do, for example, > spi-stmp.c or spi-mpc52xx.c call it ? > > On the other side, I must admit I am getting more and more confused after > looking into the code. For example, the probe function error path in > spi-mpc52xx.c accesses the master's devdata after the call to > spi_master_put(). If spi_master_put() frees the memory as we think it > does, the code would access freed memory. The same happens in the remove > path. And spi_master_put() is not always called, meaning there is either a > memory leak or I am completely confused. I'll poke through the stuff later if you won't get your answers (later == around tomorrow) > Thanks, > Guenter Best regards, Marek Vasut ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ spi-devel-general mailing list spi-devel-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/spi-devel-general
