From: Lecopzer Chen <lecopzer.chen@mediatek.com>
To: <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
Cc: <matthias.bgg@gmail.com>, <will@kernel.org>,
<alexandru.elisei@arm.com>, <sumit.garg@linaro.org>,
<linux-mediatek@lists.infradead.org>, <yj.chiang@mediatek.com>,
Lecopzer Chen <lecopzer.chen@mediatek.com>
Subject: [PATCH] kernel/watchdog_hld.c: Fix access percpu in preemptible context
Date: Thu, 17 Dec 2020 21:06:17 +0800 [thread overview]
Message-ID: <20201217130617.32202-1-lecopzer.chen@mediatek.com> (raw)
commit 367c820ef08082 ("arm64: Enable perf events based hard lockup detector")
reinitilizes lockup detector after arm64 PMU is initialized and provide
another chance for access smp_processor_id() in preemptible context.
Since hardlockup_detector_event_create() use many percpu relative variable,
just try to fix this by get/put_cpu()
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x20/0x2c
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.10.0+ #276
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x3c0
show_stack+0x20/0x6c
dump_stack+0x2f0/0x42c
check_preemption_disabled+0x1cc/0x1dc
debug_smp_processor_id+0x20/0x2c
hardlockup_detector_event_create+0x34/0x18c
hardlockup_detector_perf_init+0x2c/0x134
watchdog_nmi_probe+0x18/0x24
lockup_detector_init+0x44/0xa8
armv8_pmu_driver_init+0x54/0x78
do_one_initcall+0x184/0x43c
kernel_init_freeable+0x368/0x380
kernel_init+0x1c/0x1cc
ret_from_fork+0x10/0x30
Fixes: 367c820ef08082 ("arm64: Enable perf events based hard lockup detector")
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
---
kernel/watchdog_hld.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 247bf0b1582c..c591a1ea8eb3 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -165,7 +165,7 @@ static void watchdog_overflow_callback(struct perf_event *event,
static int hardlockup_detector_event_create(void)
{
- unsigned int cpu = smp_processor_id();
+ unsigned int cpu = get_cpu();
struct perf_event_attr *wd_attr;
struct perf_event *evt;
@@ -176,11 +176,13 @@ static int hardlockup_detector_event_create(void)
evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
watchdog_overflow_callback, NULL);
if (IS_ERR(evt)) {
+ put_cpu();
pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
PTR_ERR(evt));
return PTR_ERR(evt);
}
this_cpu_write(watchdog_ev, evt);
+ put_cpu();
return 0;
}
--
2.25.1
next reply other threads:[~2020-12-17 13:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 13:06 Lecopzer Chen [this message]
2020-12-19 13:59 ` [kernel/watchdog_hld.c] 6e37d53a67: BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h kernel test robot
2020-12-19 15:02 ` [PATCH] kernel/watchdog_hld.c: Fix access percpu in preemptible context Lecopzer Chen
2020-12-19 15:04 ` Lecopzer Chen
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