On Tue, Oct 20, 2015 at 08:01:20PM -0700, Kees Cook wrote: > On Tue, Oct 20, 2015 at 7:52 PM, Geliang Tang <geliangt...@163.com> wrote: > > On Tue, Oct 20, 2015 at 10:19:09AM -0700, Kees Cook wrote: > >> On Tue, Oct 20, 2015 at 12:39 AM, Geliang Tang <geliangt...@163.com> wrote: > >> > On Mon, Oct 19, 2015 at 10:56:54PM +0000, Luck, Tony wrote: > >> >> Thanks for looking to close out this TODO item. > >> >> > >> >> The thing that scared me about unloading pstore was what happens to > >> >> a process that is in the middle of reading some > >> >> /sys/fs/pstore/file-name-here > >> > >> Were you able to verify that this reading-while-rmmod case works correctly? > >> > >> -Kees > > > > $ sudo insmod zlib_deflate.ko > > $ sudo insmod pstore.ko > > $ lsmod > > Module Size Used by > > pstore 11225 0 > > zlib_deflate 18292 1 pstore > > > > $ sudo mount -t pstore pstore /sys/fs/pstore > > $ lsmod > > Module Size Used by > > pstore 11225 1 > > zlib_deflate 18292 1 pstore > > > > $ sudo insmod reed_solomon.ko > > $ sudo insmod ramoops.ko mem_address=0x40000000 mem_size=0x400000 > > $ lsmod > > Module Size Used by > > ramoops 9638 0 > > reed_solomon 5150 1 ramoops > > pstore 11225 2 ramoops > > zlib_deflate 18292 1 pstore > > > > $ tail -f /sys/fs/pstore/console-ramoops-0 & > > [1] 3483 > > $ lsmod > > Module Size Used by > > ramoops 9638 0 > > reed_solomon 5150 1 ramoops > > pstore 11225 3 ramoops > > zlib_deflate 18292 1 pstore > > > > $ kill -9 3483 > > $ lsmod > > Module Size Used by > > ramoops 9638 0 > > reed_solomon 5150 1 ramoops > > pstore 11225 2 ramoops > > zlib_deflate 18292 1 pstore > > > > $ sudo rmmod ramoops > > $ lsmod > > Module Size Used by > > reed_solomon 5150 0 > > pstore 11225 1 > > zlib_deflate 18292 1 pstore > > What happens if you leave the tail running and try to rmmod ramoops? > (I assume it'll just refuse.) >
It'll refuse if we try to unload pstore module. But we can unload ramoops module. Because we only increase a reference count of pstore module when the file is opened. We didn't increase ramoops module's reference count. Thanks. Geliang Tang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
