On Wed, Dec 02, 2020 at 06:36:21AM +0000, Bhaskara Budiredla wrote: > >From: Kees Cook <keescook@xxxxxxxxxxxx> > >On Mon, Nov 23, 2020 at 04:49:24PM +0530, Bhaskara Budiredla wrote: > >Why isn't this just written as: > > > >config MMC_PSTORE > > bool "Log panic/oops to a MMC buffer" > > depends on MMC_BLOCK > > select PSTORE_BLK > > help > > This option will let you create platform backend to store kmsg > > crash dumps to a user specified MMC device. This is primarily > > based on pstore/blk. > > > > The idea was to compile MMC_PSTORE as part of MMC_BLOCK driver, > provided it is optionally enabled. > The above arrangement compiles MMC_PSTORE > as module: if (CONFIG_MMC_PSTORE_BACKEND == y && CONFIG_MMC_BLOCK == m) > as static: if (CONFIG_MMC_PSTORE_BACKEND == y && CONFIG_MMC_BLOCK == y) Ah, okay. If it's a tri-state, wouldn't it track CONFIG_MMC_BLOCK's state? As in, does this work: config MMC_PSTORE tristate "Log panic/oops to a MMC buffer" depends on MMC_BLOCK select PSTORE_BLK help This option will let you create platform backend to store kmsg crash dumps to a user specified MMC device. This is primarily based on pstore/blk. > >> + if (strncmp(cxt->dev_name, disk_name, strlen(disk_name))) > >> + return; > > > >Why isn't this just strcmp()? > > The mmc disk name (disk_name) doesn't include the partition number. > strncmp is restricted to something like /dev/mmcblk0, it doesn't cover full /dev/mmcblk0pn. > The partition number check is carried out in the next statement. Okay, gotcha; thanks! > >> + dev->flags = PSTORE_FLAGS_DMESG; > > > >Can't this support more than just DMESG? I don't see anything specific to that. > >This is using pstore/zone ultimately, which can support whatever frontends it > >needs to. > > Yes, as of now the support is only for DMESG. We will extend this to other frontends > on need basis. Okay -- I assume this has mostly to do with not having erasure (below). > >> + dev->erase = NULL; > > > >No way to remove the records? > > Yes, at this time, no removal of records. Okay. (I think this might be worth mentioning in docs somewhere.) -- Kees Cook
