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| author | Peter Zijlstra <peterz@infradead.org> | 2019-07-18 11:20:09 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-20 11:27:16 +0200 |
| commit | 19dbdcb8039cff16669a05136a29180778d16d0a (patch) | |
| tree | a03d0d84fb3a5ff58df3c4da7bbd16acca5518a0 /kernel/smp.c | |
| parent | 22051d9c4a57d3b4a8b5a7407efc80c71c7bfb16 (diff) | |
| download | linux-19dbdcb8039cff16669a05136a29180778d16d0a.tar.gz linux-19dbdcb8039cff16669a05136a29180778d16d0a.tar.bz2 linux-19dbdcb8039cff16669a05136a29180778d16d0a.zip | |
smp: Warn on function calls from softirq context
It's clearly documented that smp function calls cannot be invoked from
softirq handling context. Unfortunately nothing enforces that or emits a
warning.
A single function call can be invoked from softirq context only via
smp_call_function_single_async().
The only legit context is task context, so add a warning to that effect.
Reported-by: luferry <luferry@163.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190718160601.GP3402@hirez.programming.kicks-ass.net
Diffstat (limited to 'kernel/smp.c')
| -rw-r--r-- | kernel/smp.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index 616d4d114847..7dbcb402c2fc 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -291,6 +291,14 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info, WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() && !oops_in_progress); + /* + * When @wait we can deadlock when we interrupt between llist_add() and + * arch_send_call_function_ipi*(); when !@wait we can deadlock due to + * csd_lock() on because the interrupt context uses the same csd + * storage. + */ + WARN_ON_ONCE(!in_task()); + csd = &csd_stack; if (!wait) { csd = this_cpu_ptr(&csd_data); @@ -416,6 +424,14 @@ void smp_call_function_many(const struct cpumask *mask, WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() && !oops_in_progress && !early_boot_irqs_disabled); + /* + * When @wait we can deadlock when we interrupt between llist_add() and + * arch_send_call_function_ipi*(); when !@wait we can deadlock due to + * csd_lock() on because the interrupt context uses the same csd + * storage. + */ + WARN_ON_ONCE(!in_task()); + /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */ cpu = cpumask_first_and(mask, cpu_online_mask); if (cpu == this_cpu) |