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| author | Thomas Gleixner <tglx@linutronix.de> | 2023-10-17 21:40:46 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-10-17 21:40:46 +0200 |
| commit | a940daa52167e9db8ecce82213813b735a9d9f23 (patch) | |
| tree | d5346c51351ccd1da7532cbec3127e6b73ec59c9 /kernel/smp.c | |
| parent | 32e4fa37fa667fdf53499b9de92737dc75199d8e (diff) | |
| parent | 58720809f52779dc0f08e53e54b014209d13eebb (diff) | |
| download | lwn-a940daa52167e9db8ecce82213813b735a9d9f23.tar.gz lwn-a940daa52167e9db8ecce82213813b735a9d9f23.zip | |
Merge branch 'linus' into smp/core
Pull in upstream to get the fixes so depending changes can be applied.
Diffstat (limited to 'kernel/smp.c')
| -rw-r--r-- | kernel/smp.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index 822fabb7e3e1..8c714583786b 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -46,6 +46,8 @@ static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data); static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); +static DEFINE_PER_CPU(atomic_t, trigger_backtrace) = ATOMIC_INIT(1); + static void __flush_smp_call_function_queue(bool warn_cpu_offline); int smpcfd_prepare_cpu(unsigned int cpu) @@ -253,13 +255,15 @@ static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, in *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request"); } if (cpu >= 0) { - dump_cpu_task(cpu); + if (atomic_cmpxchg_acquire(&per_cpu(trigger_backtrace, cpu), 1, 0)) + dump_cpu_task(cpu); if (!cpu_cur_csd) { pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu); arch_send_call_function_single_ipi(cpu); } } - dump_stack(); + if (firsttime) + dump_stack(); *ts1 = ts2; return false; @@ -433,9 +437,14 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline) struct llist_node *entry, *prev; struct llist_head *head; static bool warned; + atomic_t *tbt; lockdep_assert_irqs_disabled(); + /* Allow waiters to send backtrace NMI from here onwards */ + tbt = this_cpu_ptr(&trigger_backtrace); + atomic_set_release(tbt, 1); + head = this_cpu_ptr(&call_single_queue); entry = llist_del_all(head); entry = llist_reverse_order(entry); |