From 0dc9c639e6553e39c13b2c0d54c8a1b098cb95e2 Mon Sep 17 00:00:00 2001 From: Vishal Verma Date: Tue, 18 Apr 2017 20:42:35 +0200 Subject: x86/mce: Make the MCE notifier a blocking one 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 Signed-off-by: Vishal Verma Acked-by: Tony Luck Cc: Dan Williams Cc: linux-edac Cc: x86-ml Cc: Link: http://lkml.kernel.org/r/20170411224457.24777-1-vishal.l.verma@intel.com Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/mcheck/mce.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) (limited to 'arch/x86/kernel/cpu/mcheck/mce.c') diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 5accfbdee3f0..af44ebeb593f 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -123,7 +123,7 @@ 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) @@ -220,7 +220,7 @@ void mce_register_decode_chain(struct notifier_block *nb) WARN_ON(nb->priority > MCE_PRIO_LOWEST && nb->priority < MCE_PRIO_EDAC); - 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); @@ -228,7 +228,7 @@ void mce_unregister_decode_chain(struct notifier_block *nb) { atomic_dec(&num_notifiers); - 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); @@ -321,18 +321,7 @@ static void __print_mce(struct mce *m) static void print_mce(struct mce *m) { - int ret = 0; - __print_mce(m); - - /* - * 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"); } -- cgit