On Mon, Apr 24, 2017 at 09:00:19AM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.9-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 0dc9c639e6553e39c13b2c0d54c8a1b098cb95e2 Mon Sep 17 00:00:00 2001
> From: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> Date: Tue, 18 Apr 2017 20:42:35 +0200
> Subject: [PATCH] x86/mce: Make the MCE notifier a blocking one
Yeah, try this one:
---
From: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Date: Tue, 18 Apr 2017 20:42:35 +0200
Subject: [PATCH] x86/mce: Make the MCE notifier a blocking one
commit 0dc9c639e6553e39c13b2c0d54c8a1b098cb95e2 upstream.
The NFIT MCE handler callback (for handling media errors on NVDIMMs)
takes a mutex to add the location of a memory error to a list. But since
the notifier call chain for machine checks (x86_mce_decoder_chain) is
atomic, we get a lockdep splat like:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
in_atomic(): 1, irqs_disabled(): 0, pid: 4, name: kworker/0:0
[..]
Call Trace:
dump_stack
___might_sleep
__might_sleep
mutex_lock_nested
? __lock_acquire
nfit_handle_mce
notifier_call_chain
atomic_notifier_call_chain
? atomic_notifier_call_chain
mce_gen_pool_process
Convert the notifier to a blocking one which gets to run only in process
context.
Boris: remove the notifier call in atomic context in print_mce(). For
now, let's print the MCE on the atomic path so that we can make sure
they go out and get logged at least.
Fixes: 6839a6d96f4e ("nfit: do an ARS scrub on hitting a latent media error")
Reported-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Acked-by: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170411224457.24777-1-vishal.l.verma@xxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce-genpool.c | 2 +-
arch/x86/kernel/cpu/mcheck/mce-internal.h | 2 +-
arch/x86/kernel/cpu/mcheck/mce.c | 16 +++-------------
3 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce-genpool.c b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
index 93d824ec3120..040af1939460 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
@@ -85,7 +85,7 @@ void mce_gen_pool_process(void)
head = llist_reverse_order(head);
llist_for_each_entry_safe(node, tmp, head, llnode) {
mce = &node->mce;
- atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
+ blocking_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
}
}
diff --git a/arch/x86/kernel/cpu/mcheck/mce-internal.h b/arch/x86/kernel/cpu/mcheck/mce-internal.h
index cd74a3f00aea..de20902ecf23 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -13,7 +13,7 @@ enum severity_level {
MCE_PANIC_SEVERITY,
};
-extern struct atomic_notifier_head x86_mce_decoder_chain;
+extern struct blocking_notifier_head x86_mce_decoder_chain;
#define ATTR_LEN 16
#define INITIAL_CHECK_INTERVAL 5 * 60 /* 5 minutes */
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a7fdf453d895..22cda29d654e 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -120,7 +120,7 @@ static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
* CPU/chipset specific EDAC code can register a notifier call here to print
* MCE errors in a human-readable form.
*/
-ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
+BLOCKING_NOTIFIER_HEAD(x86_mce_decoder_chain);
/* Do initial initialization of a struct mce */
void mce_setup(struct mce *m)
@@ -213,13 +213,13 @@ void mce_register_decode_chain(struct notifier_block *nb)
if (nb != &mce_srao_nb && nb->priority == INT_MAX)
nb->priority -= 1;
- atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);
+ blocking_notifier_chain_register(&x86_mce_decoder_chain, nb);
}
EXPORT_SYMBOL_GPL(mce_register_decode_chain);
void mce_unregister_decode_chain(struct notifier_block *nb)
{
- atomic_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
+ blocking_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
}
EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
@@ -272,8 +272,6 @@ struct mca_msr_regs msr_ops = {
static void print_mce(struct mce *m)
{
- int ret = 0;
-
pr_emerg(HW_ERR "CPU %d: Machine Check Exception: %Lx Bank %d: %016Lx\n",
m->extcpu, m->mcgstatus, m->bank, m->status);
@@ -309,14 +307,6 @@ static void print_mce(struct mce *m)
m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
cpu_data(m->extcpu).microcode);
- /*
- * Print out human-readable details about the MCE error,
- * (if the CPU has an implementation for that)
- */
- ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
- if (ret == NOTIFY_STOP)
- return;
-
pr_emerg_ratelimited(HW_ERR "Run the above through 'mcelog --ascii'\n");
}
--
2.11.0
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.