From a2413d8b2982fb6823cdb66704938a9a345d0a7d Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Mon, 9 Feb 2015 09:36:53 -0800 Subject: [PATCH] x86/mce: Fix regression. All error records should report via /dev/mcelog I'm getting complaints from validation teams that have updated their Linux kernels from ancient versions to current. They don't see the error logs they expect. I tell the to unload any EDAC drivers[1], and things start working again. The problem is that we short-circuit the logging process if any function on the decoder chain claims to have dealt with the problem: ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m); if (ret == NOTIFY_STOP) return; The logic we used when we added this code was that we did not want to confuse users with double reports of the same error. But it turns out users are not confused - they are upset that they don't see a log where their tools used to find a log. I could also get into a long description of how the consumer of this log does more than just decode model specific details of the error. It keeps counts, tracks thresholds, takes actions and runs scripts that can alert administrators to problems. [1] We've recently compounded the problem because the acpi_extlog driver also registers for this notifier and also returns NOTIFY_STOP. Signed-off-by: Tony Luck --- arch/x86/kernel/cpu/mcheck/mce.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index d2c6116..f439c429c1 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -150,14 +150,11 @@ static struct mce_log mcelog = { void mce_log(struct mce *mce) { unsigned next, entry; - int ret = 0; /* Emit the trace record: */ trace_mce_record(mce); - ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce); - if (ret == NOTIFY_STOP) - return; + atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce); mce->finished = 0; wmb(); -- 2.7.4