Messages in this thread | | | From | Pavel Tatashin <> | Date | Tue, 3 Dec 2019 15:54:53 -0500 | Subject | Re: [PATCH] x86/tsc: Fix incorrect enabling of __use_tsc static_key |
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On Tue, Dec 3, 2019 at 3:41 PM Waiman Long <longman@redhat.com> wrote: > > After applying the commit 4763f03d3d18 ("x86/tsc: Use TSC as sched clock > early") and the commit 608008a45798 ("x86/tsc: Consolidate init code"), > some x86 systems boot up with the following warnings: > > [ 0.000000] tsc: Fast TSC calibration using PIT > [ 0.000000] tsc: Detected 2599.853 MHz processor > [ 0.000000] ------------[ cut here ]------------ > [ 0.000000] static_key_enable_cpuslocked(): static key > '__use_tsc+0x0/0x10' used before call to jump_label_init() > [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:132 static_key_enable_cpuslocked+0x7b/0x80 > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18.0-154.el8.x86_64 #1 > [ 0.000000] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017 > [ 0.000000] RIP: 0010:static_key_enable_cpuslocked+0x7b/0x80 > : > [ 0.000000] Call Trace: > [ 0.000000] ? static_key_enable+0x16/0x20 > [ 0.000000] ? setup_arch+0x43f/0xf68 > [ 0.000000] ? printk+0x58/0x6f > [ 0.000000] ? start_kernel+0x63/0x55b > [ 0.000000] ? load_ucode_bsp+0xfb/0x12e > [ 0.000000] ? secondary_startup_64+0xb7/0xc0 > [ 0.000000] ---[ end trace fc2166797a50a8e0 ]--- > : > [ 1781.404905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs > [ 1781.409905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs > [ 1781.412905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs > [ 1781.578905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs > [ 1781.973905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs > : > > In this particular case, > > setup_arch() => tsc_early_init() > => tsc_enable_sched_clock() > => static_branch_enable() > > However, jump_label_init() is called after setup_arch(). Before the > 2 commits listed above, static_branch_enable() was only called in > tsc_init() which is after jump_label_init().
Hi Waiman,
jump_label_init() is called from setup_arch(): https://soleen.com/source/xref/linux/arch/x86/kernel/setup.c?r=11a98f37#911
tsc_early_init() early init is also called from setup_arch() but later: https://soleen.com/source/xref/linux/arch/x86/kernel/setup.c?r=11a98f37#1053
I think that the kernel where this problem is seen, might be missing 8990cac6e5ea7fa57607736019fe8dca961b998f x86/jump_label: Initialize static branching early Or some other patches from that series.
Thank you, Pasha
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