Hello all, I had posted a question a few weeks ago concerning problems with perf and oprofile when running on the 2.6.33.7-rt29 kernel. I received help on how to fix the problem with perf, but no replies about oprofile. Having looked into the oprofile problem more carefully, I have a more specific question that I'm hoping somebody can answer. Below is the stack trace that I received when starting the oprofile daemon. (It's the same trace that I included in my previous post). Filling in some of the macros and inlined functions the call sequence is as follows: Ppro_setup_cntrs calls kzalloc with the GFP_ATOMIC flag set. According to kmalloc documentation this means that the call should not sleep. Kmalloc calls kmem_cache_alloc_notrace, calls kmem_cache_alloc, calls __cache_alloc, calls _slab_irq_disable, calls get_cpu_val_locked (a macro in which a call to rt_spin_lock is generated). Rt_spin_lock calls rt_spin_lock_fastlock which has the following code: /* Temporary HACK! */ 706 if (likely(!current->in_printk)) 707 might_sleep(); 708 else if (in_atomic() || irqs_disabled()) 709 /* don't grab locks for printk in atomic */ 710 return; Might_sleep is called and the kernel notes this as an error. I'm guessing that since this call did not originate in printk, might_sleep is getting called. I have very little knowledge of the inner workings of the kernel, so I don't know whether the error is with one of the functions in the call sequence, or with the check on line 706 which results in an unnecessary call to might_sleep(). I have found that although the kernel reports an oops, the oprofile daemon and the system seem to operate correctly. Can someone please confirm whether there is a real error here or whether the problem is that might_sleep is being called unnecessarily in this case? Can I assume that all is well with oprofile and ignore the kernel oops? Thanks in advance for your help. Jerry Sydir oprofile: using NMI interrupt. BUG: sleeping function called from invalid context at kernel/rtmutex.c:707 pcnt: 2 0 in_atomic(): 1, irqs_disabled(): 1, pid: 4020, name: oprofiled Pid: 4020, comm: oprofiled Not tainted 2.6.33.7-rt29 #3 Call Trace: [<c104e8c4>] ? rt_spin_lock_fastlock+0x26/0x58 [<c108ff56>] ? _slab_irq_disable+0x22/0x42 [<c109108a>] ? __kmalloc+0x7d/0xf0 [<e0071529>] ? ppro_setup_ctrs+0x29/0x1b8 [oprofile] [<e0071529>] ? ppro_setup_ctrs+0x29/0x1b8 [oprofile] [<e0070e8d>] ? nmi_cpu_setup+0x87/0xcc [oprofile] [<e0070e06>] ? nmi_cpu_setup+0x0/0xcc [oprofile] [<c102fa7b>] ? on_each_cpu+0x25/0x50 [<e0070dd9>] ? nmi_setup+0x11d/0x14a [oprofile] [<e006f133>] ? oprofile_setup+0x2d/0x86 [oprofile] [<e006fede>] ? event_buffer_open+0x42/0x60 [oprofile] [<c109363d>] ? __dentry_open+0x1a4/0x29a [<c109b09b>] ? generic_permission+0xc/0x7e [<c10937c1>] ? nameidata_to_filp+0x27/0x38 [<e006fe9c>] ? event_buffer_open+0x0/0x60 [oprofile] [<c109d214>] ? do_filp_open+0x439/0x843 [<c10808f6>] ? __do_fault+0x2bf/0x2ef [<c1090091>] ? slab_irq_enable+0x45/0x79 [<c10933a2>] ? do_sys_open+0x4c/0xe4 [<c109347e>] ? sys_open+0x1e/0x23 [<c1002750>] ? sysenter_do_call+0x12/0x26 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
