Messages in this thread Patch in this message | | | Date | Tue, 7 Nov 2017 18:53:07 +0100 | From | Borislav Petkov <> | Subject | [PATCH] x86/oprofile/ppro: Do not use __this_cpu* accessors in preemptible context |
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On Tue, Nov 07, 2017 at 08:43:40AM -0800, Linus Torvalds wrote: > So I'm adding Borislav to the cc just to maybe annoy him into sending > in a patch for this thing too..
/me runs away like the wind!
> This is the famous "you touched it last, tag you're it" model of > kernel maintainership.
Oh great, like I don't have enough crappy code to maintain already.
And besides, I'm sure Robert would've addressed it eventually, once he moves his head up from Cavium-land. Oh well, it is simple enough, lemme take care of it. :-)
Fengguang, please run it to confirm.
Thx.
--- From: Borislav Petkov <bp@suse.de> Subject: [PATCH] x86/oprofile/ppro: Do not use __this_cpu* accessors in preemptible context
The warning below says it all. And we should not have used those accessors in the first place: it is PPro so no mixed silicon revisions and thus can simply use boot_cpu_data.
BUG: using __this_cpu_read() in preemptible [00000000] code: swapper/0/1 caller is __this_cpu_preempt_check CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.0-rc8 #4 Call Trace: dump_stack check_preemption_disabled ? do_early_param __this_cpu_preempt_check arch_perfmon_init op_nmi_init ? alloc_pci_root_info oprofile_arch_init oprofile_init do_one_initcall ...
Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Fix-creation-mandated-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Robert Richter <rric@kernel.org> Cc: x86@kernel.org --- arch/x86/oprofile/op_model_ppro.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c index 350f7096baac..1c3b400b05ce 100644 --- a/arch/x86/oprofile/op_model_ppro.c +++ b/arch/x86/oprofile/op_model_ppro.c @@ -212,8 +212,9 @@ static void arch_perfmon_setup_counters(void) eax.full = cpuid_eax(0xa); /* Workaround for BIOS bugs in 6/15. Taken from perfmon2 */ - if (eax.split.version_id == 0 && __this_cpu_read(cpu_info.x86) == 6 && - __this_cpu_read(cpu_info.x86_model) == 15) { + if (eax.split.version_id == 0 && + boot_cpu_data.x86 == 6 && + boot_cpu_data.x86_model == 15) { eax.split.version_id = 2; eax.split.num_counters = 2; eax.split.bit_width = 40; -- 2.13.0 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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