On 02/01/2018 04:41 PM, Taras Kondratiuk wrote: > Quoting Mimi Zohar (2018-02-01 13:51:52) >> On Thu, 2018-02-01 at 11:09 -0600, Rob Landley wrote: >>> On 02/01/2018 09:55 AM, Mimi Zohar wrote: >>>> On Thu, 2018-02-01 at 09:20 -0600, Rob Landley wrote: >>>> >>>>>> With your patch and specifying "root=tmpfs", dracut is complaining: >>>>>> >>>>>> dracut: FATAL: Don't know how to handle 'root=tmpfs' >>>>>> dracut: refusing to continue >>>>> >>>>> [googles]... I do not understand why this package exists. >>>>> >>>>> If you're switching to another root filesystem, using a tool that >>>>> wikipedia[citation needed] says has no purpose but to switch to another >>>>> root filesystem, (so let's reproduce the kernel infrastructure in >>>>> userspace while leaving it the kernel too)... why do you need initramfs >>>>> to be tmpfs? You're using it for half a second, then discarding it, >>>>> what's the point of it being tmpfs? >>>> >>>> Unlike the kernel image which is signed by the distros, the initramfs >>>> doesn't come signed, because it is built on the target system. Even >>>> if the initramfs did come signed, it is beneficial to measure and >>>> appraise the individual files in the initramfs. >>> >>> You can still shoot yourself in the foot with tmpfs. People mount a /run >>> and a /tmp and then as a normal user you can go >>> https://twitter.com/landley/status/959103235305951233 and maybe the >>> default should be a little more clever there... >>> >>> I'll throw it on the todo heap. :) >>> >>>>> Sigh. If people are ok with having rootfs just be tmpfs whenever tmpfs >>>>> is configured in, even when you're then going to overmount it with >>>>> something else like you're doing, let's just _remove_ the test. If it >>>>> can be tmpfs, have it be tmpfs. >>>> >>>> Very much appreciated! >>> >>> Not yet tested, but something like the attached? (Sorry for the >>> half-finished doc changes in there, I'm at work and have a 5 minute >>> break. I can test properly this evening if you don't get to it...) >> >> Yes, rootfs is being mounted as tmpfs. > > I don't think you can unconditionally replace ramfs with initramfs by > default. Their behavior is different in some cases (e.g. pivot_root vs > switch_root) Both are switch_root, you can't pivot_root off of either one. (Yes, I hit that bug and reported it, and they fixed it, back in the day... http://lists.busybox.net/pipermail/busybox/2006-March/053529.html ) > and it can break many systems that expect ramfs by default. The use case I told Mimi about off-list (since they stopped cc:ing the list in one of their replies but the conversation continued) was the guy who was extracting an initramfs bigger than 50% of system memory, which worked with initramfs but failed with initmpfs. A quick google didn't find the original message but it resulted in this blog entry from the affected party: http://www.lightofdawn.org/blog/?viewDetailed=00128 I.E. yeah, I know, I need to redo these patches tonight. Rob -- To unsubscribe from this list: send the line "unsubscribe initramfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
