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authorIngo Molnar <mingo@kernel.org>2020-10-09 08:21:56 +0200
committerIngo Molnar <mingo@kernel.org>2020-10-09 08:21:56 +0200
commitb36c830f8c9b13bfe69b117e879153776c19ad82 (patch)
tree151b7e91a49ff894e11e0b24c0e8cf9675dd5d91 /lib
parent583090b1b8232e6eae243a9009699666153a13a9 (diff)
parent6fe208f63a79f4f726f3be2b78ea3dd40487b657 (diff)
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull v5.10 RCU changes from Paul E. McKenney: - Debugging for smp_call_function(). - Strict grace periods for KASAN. The point of this series is to find RCU-usage bugs, so the corresponding new RCU_STRICT_GRACE_PERIOD Kconfig option depends on both DEBUG_KERNEL and RCU_EXPERT, and is further disabled by dfefault. Finally, the help text includes a goodly list of scary caveats. - New smp_call_function() torture test. - Torture-test updates. - Documentation updates. - Miscellaneous fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug21
-rw-r--r--lib/nmi_backtrace.c6
2 files changed, 26 insertions, 1 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 0c781f912f9f..a28850bf9747 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1367,6 +1367,27 @@ config WW_MUTEX_SELFTEST
Say M if you want these self tests to build as a module.
Say N if you are unsure.
+config SCF_TORTURE_TEST
+ tristate "torture tests for smp_call_function*()"
+ depends on DEBUG_KERNEL
+ select TORTURE_TEST
+ help
+ This option provides a kernel module that runs torture tests
+ on the smp_call_function() family of primitives. The kernel
+ module may be built after the fact on the running kernel to
+ be tested, if desired.
+
+config CSD_LOCK_WAIT_DEBUG
+ bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
+ depends on DEBUG_KERNEL
+ depends on 64BIT
+ default n
+ help
+ This option enables debug prints when CPUs are slow to respond
+ to the smp_call_function*() IPI wrappers. These debug prints
+ include the IPI handler function currently executing (if any)
+ and relevant stack traces.
+
endmenu # lock debugging
config TRACE_IRQFLAGS
diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index 15ca78e1c7d4..8abe1870dba4 100644
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -85,12 +85,16 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
put_cpu();
}
+// Dump stacks even for idle CPUs.
+static bool backtrace_idle;
+module_param(backtrace_idle, bool, 0644);
+
bool nmi_cpu_backtrace(struct pt_regs *regs)
{
int cpu = smp_processor_id();
if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
- if (regs && cpu_in_idle(instruction_pointer(regs))) {
+ if (!READ_ONCE(backtrace_idle) && regs && cpu_in_idle(instruction_pointer(regs))) {
pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n",
cpu, (void *)instruction_pointer(regs));
} else {