Messages in this thread | | | Date | Fri, 30 Aug 2013 08:36:58 -0700 | From | "H. Peter Anvin" <> | Subject | Re: x86-32: Early microcode loading stumbles over disabled DYNAMIC_FTRACE |
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On 08/23/2013 09:40 AM, Jan Kiszka wrote: > Hi all, > > 32-bit kernels currently crash/reboot in early microcode loading when > non-dynamic function tracing is enabled. Several functions in that path > get instrumented with mcount, but its non-dynamic implementation does > not work before paging is enabled (it accesses global variables at wrong > addresses). > > Below some hunks to get it working again - at least in the absence of > any microcode in the initrd. Marking all involved functions as __init is > another option (as __init implies notrace). But I bet there is more > hidden. I see e.g. a pr_warn() in find_cpio_init that should trigger the > issue as well if we hit the error it reports (btw. printing at this > point of the boot should not work anyway, should it?). > > Better ideas? > > Jan >
A better idea would be for the mcount/__fentry__ function to simply return until the function tracing stuff is actually ready.
-hpa
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