| Message ID | 20200612115200.1006881-1-vicamo.yang@canonical.com |
|---|---|
| Headers | show |
| Series | Fix boot regression caused by a disabled PIT | expand |
On 2020-06-12 19:51:59 , You-Sheng Yang wrote: > BugLink: https://bugs.launchpad.net/bugs/1856387 > > [Impact] > In bug 1840239, HPET is disabled on some systems for they caused TSC > being marked unstable while it is not. This caused an regression as bug > 1851216 that some systems may then hang at early, so a fix cherry picked > back from v5.3-rc1. However, this fix also introduce yet another > regression that some other users may hang at boot while PIT is diabled > in the previous fix. > > [Fix] > Commit 979923871f69 ("x86/timer: Don't skip PIT setup when APIC is > disabled or in legacy mode") from v5.6-rc1, also backported to v5.4.19 > and v5.5.3, fixes PIT setup in this case. > > [Test Case] > Simply boot a patch kernel on systems affected and it shouldn't hang. > > [Regression Potential] > Low. Stable patch and trivial backport. > > [Other Info] > The same fix for bug 1851216 was also backported to Disco and Eoan, but > they were then fixed with this 979923871f69 commit backported in bug > 1866858 and bug 1867051, which pulls v5.4 stable patches into Disco and > Eoan correspondingly, leaving B/OEM-B the only victims so far. > > Thomas Gleixner (1): > x86/timer: Don't skip PIT setup when APIC is disabled or in legacy > mode > > arch/x86/include/asm/apic.h | 2 ++ > arch/x86/include/asm/x86_init.h | 2 ++ > arch/x86/kernel/apic/apic.c | 23 ++++++++++++++++++----- > arch/x86/kernel/time.c | 12 ++++++++++-- > arch/x86/kernel/x86_init.c | 1 + > arch/x86/xen/enlighten_pv.c | 1 + > 6 files changed, 34 insertions(+), 7 deletions(-) > > -- > 2.27.0.rc0 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
Acked-By: AceLan Kao <acelan.kao@canonical.com>
BugLink: https://bugs.launchpad.net/bugs/1856387 [Impact] In bug 1840239, HPET is disabled on some systems for they caused TSC being marked unstable while it is not. This caused an regression as bug 1851216 that some systems may then hang at early, so a fix cherry picked back from v5.3-rc1. However, this fix also introduce yet another regression that some other users may hang at boot while PIT is diabled in the previous fix. [Fix] Commit 979923871f69 ("x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode") from v5.6-rc1, also backported to v5.4.19 and v5.5.3, fixes PIT setup in this case. [Test Case] Simply boot a patch kernel on systems affected and it shouldn't hang. [Regression Potential] Low. Stable patch and trivial backport. [Other Info] The same fix for bug 1851216 was also backported to Disco and Eoan, but they were then fixed with this 979923871f69 commit backported in bug 1866858 and bug 1867051, which pulls v5.4 stable patches into Disco and Eoan correspondingly, leaving B/OEM-B the only victims so far. Thomas Gleixner (1): x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode arch/x86/include/asm/apic.h | 2 ++ arch/x86/include/asm/x86_init.h | 2 ++ arch/x86/kernel/apic/apic.c | 23 ++++++++++++++++++----- arch/x86/kernel/time.c | 12 ++++++++++-- arch/x86/kernel/x86_init.c | 1 + arch/x86/xen/enlighten_pv.c | 1 + 6 files changed, 34 insertions(+), 7 deletions(-)