On Tue, 06 Mar 2012 13:00:01 +1100 Steven Haigh <netwiz@xxxxxxxxx> wrote: > On 6/03/2012 7:01 AM, NeilBrown wrote: > > On Tue, 06 Mar 2012 05:53:28 +1100 Steven Haigh<netwiz@xxxxxxxxx> wrote: > > > >> On 6/03/2012 1:52 AM, John Robinson wrote: > >>> On 05/03/2012 13:03, Steven Haigh wrote: > >>>> I've noticed that recently I've managed to get a ton of messages like > >>>> this at boot: > >>>> > >>>> mdadm: sending ioctl 1261 to a partition! > >>>> mdadm: sending ioctl 800c0910 to a partition! > >>> > >>> It's probably harmless. > >>> > >>> http://lists.debian.org/debian-kernel/2012/01/msg01105.html says "This > >>> warning was introduced as part of the fix for CVE-2011-4127" > >>> > >>> https://bugzilla.redhat.com/show_bug.cgi?id=783955#c4 says "Actually, > >>> the warning seems a false positive to me" > >> > >> I did see these - and I probably should have mentioned it in the > >> original post. Naughty me for posting at times I should really be asleep. > >> > >> The general jist of it seemed to be "it always failed before, now we > >> just know about it". What makes me wonder is that if it always failed > >> before, why do we do it in the first place? > >> > > > > 800c0910 is 'are you an md device'. So failure is a valid response. > > > > 1261 is flush-bufs. I hope that does still work on partitions.... > > Thanks Neil, Any ideas how I can test this to check if flush-bufs is > working? While I'm not a code junkie these days - I'm great at picking > holes in thing ;) Read the code.... In block/ioctl.c case BLKFLSBUF: if (!capable(CAP_SYS_ADMIN)) return -EACCES; ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg); /* -EINVAL to handle old uncorrected drivers */ if (ret != -EINVAL && ret != -ENOTTY) return ret; lock_kernel(); fsync_bdev(bdev); invalidate_bdev(bdev); unlock_kernel(); return 0; So it is still called fsync_bdev and invalidate_bdev as long as the ioctl function for the underlying disk returns -EINVAL or -ENOTTY. The function that shows that warning is scsi_verify_blk_ioctl in block/scsi_ioctl.c The worst it can do is return -ENOTTY, and that is safe. So the warning is bogus, the code still works. NeilBrown > > I picked it up as it only seemed to be visible in 2.6.32.56. I don't > recall seeing it in any previous 2.6.32.x kernel. >
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