The ia64_mca_cpe_int_handler() and the ia64_mca_cmc_int_handler() are not safe against nested interrupts. The interrupts are enabled too early. The interrupts should remain blocked while we are inside the lock- protected region. (See ..._history_lock.) The interrupts will be enabled in ia64_mca_log_sal_error_record() unless it is called from the MCA/INIT handlers. Please have a look at this patch. Thanks, Zoltan Menyhart Signed-off-by: Zoltan Menyhart, <Zoltan.Menyhart@xxxxxxxx>
--- linux-2.6.24-old/arch/ia64/kernel/mca.c 2008-02-22 18:09:12.000000000 +0100 +++ linux-2.6.24/arch/ia64/kernel/mca.c 2008-02-22 18:09:26.000000000 +0100 @@ -423,19 +423,25 @@ * and wakes up any processes waiting for error records. * * Inputs : sal_info_type (Type of error record MCA/CMC/CPE) - * FIXME: remove MCA and irq_safe. + * irq_safe (TRUE if not called from the MCA/INIT handlers) */ static void -ia64_mca_log_sal_error_record(int sal_info_type) +ia64_mca_log_sal_error_record(int sal_info_type, int irq_safe) { u8 *buffer; sal_log_record_header_t *rh; u64 size; - int irq_safe = sal_info_type != SAL_INFO_TYPE_MCA; #ifdef IA64_MCA_DEBUG_INFO static const char * const rec_name[] = { "MCA", "INIT", "CMC", "CPE" }; #endif + if (irq_safe){ + /* SAL spec says: SAL_GET_STATE_INFO() and SAL_CLEAR_STATE_INFO() + * should be called with interrupts enabled, unless we are in + * MCA/INIT handlers. + */ + local_irq_enable(); + } size = ia64_log_get(sal_info_type, &buffer, irq_safe); if (!size) return; @@ -512,9 +518,6 @@ IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n", __FUNCTION__, cpe_irq, smp_processor_id()); - /* SAL spec states this should run w/ interrupts enabled */ - local_irq_enable(); - spin_lock(&cpe_history_lock); if (!cpe_poll_enabled && cpe_vector >= 0) { @@ -553,8 +556,8 @@ spin_unlock(&cpe_history_lock); out: /* Get the CPE error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CPE); - + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CPE, + 1 /* not called from the MCA/INIT handlers */); return IRQ_HANDLED; } @@ -1245,7 +1248,8 @@ } /* Get the MCA error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_MCA); + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_MCA, + 0 /* called from the MCA/INIT handlers */); /* MCA error recovery */ recover = (ia64_mca_ucmc_extension @@ -1322,9 +1326,6 @@ IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n", __FUNCTION__, cmc_irq, smp_processor_id()); - /* SAL spec states this should run w/ interrupts enabled */ - local_irq_enable(); - spin_lock(&cmc_history_lock); if (!cmc_polling_enabled) { int i, count = 1; /* we know 1 happened now */ @@ -1367,7 +1368,8 @@ spin_unlock(&cmc_history_lock); out: /* Get the CMC error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CMC); + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CMC, + 1 /* not called from the MCA/INIT handlers */); return IRQ_HANDLED; }
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