Messages in this thread Patch in this message | | | From | Tang Chen <> | Subject | [PATCH v2 2/2] Do not change worker's running cpu in cmci_rediscover(). | Date | Fri, 19 Oct 2012 13:45:28 +0800 |
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cmci_rediscover() used set_cpus_allowed_ptr() to change the current process's running cpu, and migrate itself to the dest cpu. But worker processes are not allowed to be migrated. If current is a worker, the worker will be migrated to another cpu, but the corresponding worker_pool is still on the original cpu.
In this case, the following BUG_ON in try_to_wake_up_local() will be triggered: BUG_ON(rq != this_rq());
This will cause the kernel panic.
This patch removes the set_cpus_allowed_ptr() call, and put the cmci rediscover jobs onto all the other cpus using system_wq. This could bring some delay for the jobs.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> --- arch/x86/kernel/cpu/mcheck/mce_intel.c | 30 +++++++++++++++++------------- 1 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c index 481d152..d8f0da6 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c @@ -163,34 +163,38 @@ void cmci_clear(void) raw_spin_unlock_irqrestore(&cmci_discover_lock, flags); } +static long cmci_rediscover_work_func(void *arg) +{ + int banks; + + /* Recheck banks in case CPUs don't all have the same */ + if (cmci_supported(&banks)) + cmci_discover(banks, 0); + + return 0; +} + /* * After a CPU went down cycle through all the others and rediscover * Must run in process context. */ void cmci_rediscover(int dying) { - int banks; - int cpu; - cpumask_var_t old; + int cpu, banks; if (!cmci_supported(&banks)) return; - if (!alloc_cpumask_var(&old, GFP_KERNEL)) - return; - cpumask_copy(old, ¤t->cpus_allowed); for_each_online_cpu(cpu) { WARN_ON_ONCE(cpu == dying); - if (set_cpus_allowed_ptr(current, cpumask_of(cpu))) + if (cpu == smp_processor_id()) { + cmci_rediscover_work_func(NULL); continue; - /* Recheck banks in case CPUs don't all have the same */ - if (cmci_supported(&banks)) - cmci_discover(banks, 0); - } + } - set_cpus_allowed_ptr(current, old); - free_cpumask_var(old); + work_on_cpu(cpu, cmci_rediscover_work_func, NULL); + } } /* -- 1.7.1
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