[PATCH] x86/mce: Fix timer interval adjustment after logging a MCE event

lirongqing
2026-01-12T08:44:47Z

From: Li RongQing <lirongqing@baidu.com>

Since commit 011d82611172 ("RAS: Add a Corrected Errors Collector"),
mce_notify_irq() in should_enable_timer() always returns false even
when an MCE event is logged, because bit 0 of mce_need_notify is not
set in mce_log. This prevents the timer interval from being properly
adjusted.

Fix this by modifying machine_check_poll() to return a boolean indicating
whether an MCE was logged, and update mc_poll_banks() to propagate this
return value. The timer interval logic in mce_timer_fn() now uses this
return value directly instead of relying on mce_notify_irq().

Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
arch/x86/include/asm/mce.h | 2 +-
arch/x86/kernel/cpu/mce/core.c | 17 +++++++++++------
arch/x86/kernel/cpu/mce/intel.c | 8 ++++++--
arch/x86/kernel/cpu/mce/internal.h | 2 +-
4 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 2d98886..fb9eab4 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -303,7 +303,7 @@ enum mcp_flags {
MCP_QUEUE_LOG = BIT(2), /* only queue to genpool */
};

-void machine_check_poll(enum mcp_flags flags, mce_banks_t *b);
+bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b);

DECLARE_PER_CPU(struct mce, injectm);

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 3444002..8d42691 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -813,10 +813,11 @@ static void clear_bank(struct mce *m)
* is already totally * confused. In this case it's likely it will
* not fully execute the machine check handler either.
*/
-void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
+bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
{
struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array);
struct mce_hw_err err;
+ bool logged = false;
struct mce *m;
int i;

@@ -868,6 +869,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
else
mce_log(&err);

+ logged = true;
clear_it:
clear_bank(m);
}
@@ -878,6 +880,8 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
*/

sync_core();
+
+ return logged;
}
EXPORT_SYMBOL_GPL(machine_check_poll);

@@ -1776,12 +1780,12 @@ static void __start_timer(struct timer_list *t, unsigned long interval)
local_irq_restore(flags);
}

-static void mc_poll_banks_default(void)
+static bool mc_poll_banks_default(void)
{
- machine_check_poll(0, this_cpu_ptr(&mce_poll_banks));
+ return machine_check_poll(0, this_cpu_ptr(&mce_poll_banks));
}

-void (*mc_poll_banks)(void) = mc_poll_banks_default;
+bool (*mc_poll_banks)(void) = mc_poll_banks_default;

static bool should_enable_timer(unsigned long iv)
{
@@ -1792,19 +1796,20 @@ static void mce_timer_fn(struct timer_list *t)
{
struct timer_list *cpu_t = this_cpu_ptr(&mce_timer);
unsigned long iv;
+ bool logged = false;

WARN_ON(cpu_t != t);

iv = __this_cpu_read(mce_next_interval);

if (mce_available(this_cpu_ptr(&cpu_info)))
- mc_poll_banks();
+ logged = mc_poll_banks();

/*
* Alert userspace if needed. If we logged an MCE, reduce the polling
* interval, otherwise increase the polling interval.
*/
- if (mce_notify_irq())
+ if (logged)
iv = max(iv / 2, (unsigned long) HZ/100);
else
iv = min(iv * 2, round_jiffies_relative(check_interval * HZ));
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
index 4655223..a3d2730 100644
--- a/arch/x86/kernel/cpu/mce/intel.c
+++ b/arch/x86/kernel/cpu/mce/intel.c
@@ -395,11 +395,15 @@ void cmci_disable_bank(int bank)
}

/* Bank polling function when CMCI is disabled. */
-static void cmci_mc_poll_banks(void)
+static bool cmci_mc_poll_banks(void)
{
+ bool logged;
+
spin_lock(&cmci_poll_lock);
- machine_check_poll(0, this_cpu_ptr(&mce_poll_banks));
+ logged = machine_check_poll(0, this_cpu_ptr(&mce_poll_banks));
spin_unlock(&cmci_poll_lock);
+
+ return logged;
}

void intel_init_cmci(void)
diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
index a31cf98..7bf2360 100644
--- a/arch/x86/kernel/cpu/mce/internal.h
+++ b/arch/x86/kernel/cpu/mce/internal.h
@@ -348,5 +348,5 @@ static __always_inline u32 mca_msr_reg(int bank, enum mca_msr reg)
return 0;
}

-extern void (*mc_poll_banks)(void);
+extern bool (*mc_poll_banks)(void);
#endif /* __X86_MCE_INTERNAL_H__ */
--
2.9.4