Commit e1d9694cae722d00a94fb58f901aa69c9c324a16
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Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
…/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh generic-ipi: Fix deadlock in __smp_call_function_single
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include/linux/rcupdate.h
| ... | ... | @@ -454,7 +454,7 @@ |
| 454 | 454 | * Makes rcu_dereference_check() do the dirty work. |
| 455 | 455 | */ |
| 456 | 456 | #define rcu_dereference_bh(p) \ |
| 457 | - rcu_dereference_check(p, rcu_read_lock_bh_held()) | |
| 457 | + rcu_dereference_check(p, rcu_read_lock_bh_held() || irqs_disabled()) | |
| 458 | 458 | |
| 459 | 459 | /** |
| 460 | 460 | * rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched |
kernel/smp.c
| ... | ... | @@ -365,9 +365,10 @@ |
| 365 | 365 | EXPORT_SYMBOL_GPL(smp_call_function_any); |
| 366 | 366 | |
| 367 | 367 | /** |
| 368 | - * __smp_call_function_single(): Run a function on another CPU | |
| 368 | + * __smp_call_function_single(): Run a function on a specific CPU | |
| 369 | 369 | * @cpu: The CPU to run on. |
| 370 | 370 | * @data: Pre-allocated and setup data structure |
| 371 | + * @wait: If true, wait until function has completed on specified CPU. | |
| 371 | 372 | * |
| 372 | 373 | * Like smp_call_function_single(), but allow caller to pass in a |
| 373 | 374 | * pre-allocated data structure. Useful for embedding @data inside |
| 374 | 375 | |
| ... | ... | @@ -376,8 +377,10 @@ |
| 376 | 377 | void __smp_call_function_single(int cpu, struct call_single_data *data, |
| 377 | 378 | int wait) |
| 378 | 379 | { |
| 379 | - csd_lock(data); | |
| 380 | + unsigned int this_cpu; | |
| 381 | + unsigned long flags; | |
| 380 | 382 | |
| 383 | + this_cpu = get_cpu(); | |
| 381 | 384 | /* |
| 382 | 385 | * Can deadlock when called with interrupts disabled. |
| 383 | 386 | * We allow cpu's that are not yet online though, as no one else can |
| ... | ... | @@ -387,7 +390,15 @@ |
| 387 | 390 | WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled() |
| 388 | 391 | && !oops_in_progress); |
| 389 | 392 | |
| 390 | - generic_exec_single(cpu, data, wait); | |
| 393 | + if (cpu == this_cpu) { | |
| 394 | + local_irq_save(flags); | |
| 395 | + data->func(data->info); | |
| 396 | + local_irq_restore(flags); | |
| 397 | + } else { | |
| 398 | + csd_lock(data); | |
| 399 | + generic_exec_single(cpu, data, wait); | |
| 400 | + } | |
| 401 | + put_cpu(); | |
| 391 | 402 | } |
| 392 | 403 | |
| 393 | 404 | /** |