[tip:ras/core] x86/mce: Do not enter deferred errors into the generic pool twice

tip-bot for Tony Luck
2015-11-24T09:32:11Z

Commit-ID: 8b38937b7ab55e93065a14c88753b1fe83e93c60
Gitweb: http://git.kernel.org/tip/8b38937b7ab55e93065a14c88753b1fe83e93c60
Author: Tony Luck <tony.luck@intel.com>
AuthorDate: Tue, 24 Nov 2015 08:41:17 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 24 Nov 2015 09:12:35 +0100

x86/mce: Do not enter deferred errors into the generic pool twice

We used to have a special ring buffer for deferred errors that
was used to mark problem pages. We replaced that with a generic
pool. Then later converted mce_log() to also use the same pool.
As a result, we end up adding all deferred errors to the pool
twice.

Rearrange this code. Make sure to set the m.severity and
m.usable_addr fields for deferred errors. Then if flags and
mca_cfg.dont_log_ce mean we call mce_log() we are done, because
that will add this entry to the generic pool.

If we skipped mce_log(), then we still want to take action for
the deferred error, so add to the pool.

Change the name of the boolean "error_logged" to "error_seen",
we should set it whether of not we logged an error because the
return value from machine_check_poll() is used to decide whether
storms have subsided or not.

Reported-by: Gong Chen <gong.chen@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1448350880-5573-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/mcheck/mce.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index c5b0d56..6531cb4 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -567,7 +567,7 @@ DEFINE_PER_CPU(unsigned, mce_poll_count);
*/
bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
{
- bool error_logged = false;
+ bool error_seen = false;
struct mce m;
int severity;
int i;
@@ -601,6 +601,8 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
(m.status & (mca_cfg.ser ? MCI_STATUS_S : MCI_STATUS_UC)))
continue;

+ error_seen = true;
+
mce_read_aux(&m, i);

if (!(flags & MCP_TIMESTAMP))
@@ -608,17 +610,10 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)

severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);

- /*
- * In the cases where we don't have a valid address after all,
- * do not add it into the ring buffer.
- */
if (severity == MCE_DEFERRED_SEVERITY && memory_error(&m)) {
if (m.status & MCI_STATUS_ADDRV) {
m.severity = severity;
m.usable_addr = mce_usable_address(&m);
-
- if (!mce_gen_pool_add(&m))
- mce_schedule_work();
}
}

@@ -626,9 +621,16 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
* Don't get the IP here because it's unlikely to
* have anything to do with the actual error location.
*/
- if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce) {
- error_logged = true;
+ if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce)
mce_log(&m);
+ else if (m.usable_addr) {
+ /*
+ * Although we skipped logging this, we still want
+ * to take action. Add to the pool so the registered
+ * notifiers will see it.
+ */
+ if (!mce_gen_pool_add(&m))
+ mce_schedule_work();
}

/*
@@ -644,7 +646,7 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)

sync_core();

- return error_logged;
+ return error_seen;
}
EXPORT_SYMBOL_GPL(machine_check_poll);