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Hi, |
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please review the news item below: |
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- I am not 100% happy with the title but the 50 char limit |
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doesn't allow any more details. |
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- No Display-If condition because it is neither a genkernel nor |
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kexec-tools issue. We maybe even have additional packages |
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which are appending to kernel command-line I am not aware of. |
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|
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- In theory this shouldn't be a news for anyone: If you don't |
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use a persistent device name, you are basically asking for |
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troubles like that. However, people just using kexec from |
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kexec-tools package maybe unaware that auto-detection of |
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ROOT device which is the default might cause trouble like |
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that because it won't use persistent names. |
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|
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- Experiencing a boot failure is always bad -- especially for |
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headless/remote systems so a warning shouldn't hurt. |
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|
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- Latest kexec-tools ebuild in repository now also warns user |
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in pkg_postinst, see |
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https://gitweb.gentoo.org/repo/gentoo.git/tree/sys-apps/kexec-tools/kexec-tools-2.0.20-r3.ebuild?id=61c03ffab76740c0420e3c8a3185d047d461f7a7#n111 |
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--- |
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Title: Multiple root kernel command-line arguments |
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Author: Thomas Deutschmann <whissi@g.o> |
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Posted: 2020-08-05 |
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Revision: 1 |
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News-Item-Format: 2.0 |
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|
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Due to genkernel-4.1 development which is changing device manager |
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from MDEV to (E)UDEV it was noticed that some tools like kexec |
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append an additional root argument to kernel command-line. If these |
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tools will set root to a non-persistent device name like |
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root=/dev/dm-3, the next boot might fail if there is *no* root device |
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named like that in start environment (i.e. initramfs). |
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|
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While kexec's runscript was changed in >=sys-apps/kexec-tools-2.0.20-r2 |
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to no longer append root kernel command-line argument when an option |
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like "--reuse-cmdline" (default) is used, a cold reboot *without* |
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kexec maybe needed to restore kernel command-line. |
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NOTE: This issue is *not* specific to kexec or genkernel usage. |
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Kernel will always use last set root kernel command-line argument. |
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Any tool which might be appending root argument without a persistent |
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device name might cause a boot failure if system cannot find that |
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referenced root device during boot. |
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To avoid boot problems user should revise their current kernel |
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command-line (/proc/cmdline) to ensure that only *one* root kernel |
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command-line argument is set. The usage of persistent device names |
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like root=UUID=<...> is highly recommended. |
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-- |
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Regards, |
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Thomas Deutschmann / Gentoo Linux Developer |
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C4DD 695F A713 8F24 2AA1 5638 5849 7EE5 1D5D 74A5 |
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