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| author | Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> | 2009-05-08 10:28:40 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-08 11:03:26 +0200 |
| commit | e5299926d7459d9fa7c7f856983147817aedb10e (patch) | |
| tree | e4ea790efd6d6bb5bd41a9969b10e917f9d18678 | |
| parent | x86: xen, i386: reserve Xen pagetables (diff) | |
| download | linux-e5299926d7459d9fa7c7f856983147817aedb10e.tar.xz linux-e5299926d7459d9fa7c7f856983147817aedb10e.zip | |
x86: MCE: make cmci_discover_lock irq-safe
Lockdep reports the warning below when Li tries to offline one cpu:
[ 110.835487] =================================
[ 110.835616] [ INFO: inconsistent lock state ]
[ 110.835688] 2.6.30-rc4-00336-g8c9ed89 #52
[ 110.835757] ---------------------------------
[ 110.835828] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[ 110.835908] swapper/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[ 110.835982] (cmci_discover_lock){?.+...}, at: [<ffffffff80236dc0>] cmci_clear+0x30/0x9b
cmci_clear() can be called via smp_call_function_single().
It is better to disable interrupt while holding cmci_discover_lock,
to turn it into an irq-safe lock - we can deadlock otherwise.
[ Impact: fix possible deadlock in the MCE code ]
Reported-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A03ED38.8000700@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Shaohua Li<shaohua.li@intel.com>
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce_intel_64.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel_64.c b/arch/x86/kernel/cpu/mcheck/mce_intel_64.c index d6b72df89d69..cef3ee30744b 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_intel_64.c +++ b/arch/x86/kernel/cpu/mcheck/mce_intel_64.c @@ -151,10 +151,11 @@ static void print_update(char *type, int *hdr, int num) static void cmci_discover(int banks, int boot) { unsigned long *owned = (void *)&__get_cpu_var(mce_banks_owned); + unsigned long flags; int hdr = 0; int i; - spin_lock(&cmci_discover_lock); + spin_lock_irqsave(&cmci_discover_lock, flags); for (i = 0; i < banks; i++) { u64 val; @@ -184,7 +185,7 @@ static void cmci_discover(int banks, int boot) WARN_ON(!test_bit(i, __get_cpu_var(mce_poll_banks))); } } - spin_unlock(&cmci_discover_lock); + spin_unlock_irqrestore(&cmci_discover_lock, flags); if (hdr) printk(KERN_CONT "\n"); } @@ -211,13 +212,14 @@ void cmci_recheck(void) */ void cmci_clear(void) { + unsigned long flags; int i; int banks; u64 val; if (!cmci_supported(&banks)) return; - spin_lock(&cmci_discover_lock); + spin_lock_irqsave(&cmci_discover_lock, flags); for (i = 0; i < banks; i++) { if (!test_bit(i, __get_cpu_var(mce_banks_owned))) continue; @@ -227,7 +229,7 @@ void cmci_clear(void) wrmsrl(MSR_IA32_MC0_CTL2 + i, val); __clear_bit(i, __get_cpu_var(mce_banks_owned)); } - spin_unlock(&cmci_discover_lock); + spin_unlock_irqrestore(&cmci_discover_lock, flags); } /* |