Re: How to debug complete kernel lock-ups
Hi John, On Tue, 2007-10-23 at 18:11 +0200, John Sigler wrote: [...] I've built a debug 2.6.22.1-rt9 kernel, hoping to get the kernel to dump something, anything. Just curious: Is it works with non -rt kernel? Ciao, Alessio - To unsubscribe from this list: send the line unsubscribe linux-rt-users in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How to debug complete kernel lock-ups
John Sigler wrote: I have an x86 system with two PCI slots, in which I inserted two specialized output cards (Dektec DTA-105). http://www.dektec.com/Products/DTA-105/ (They provide an open source driver.) My problem is: when I write to the 4 ports (each card has 2 ports) at the same time (not really at the same time because I have a uni-processor system, so within a short time frame is more accurate) the system *completely* locks up. The manufacturer told me they had seen the problem in their lab. I'm just trying to provide some helpful debug output to speed up the process of fixing the problem :-) I've built a debug 2.6.22.1-rt9 kernel, hoping to get the kernel to dump something, anything. +CONFIG_KALLSYMS_ALL=y +CONFIG_PCI_DEBUG=y +CONFIG_DEBUG_DRIVER=y +CONFIG_PRINTK_TIME=y +CONFIG_MAGIC_SYSRQ=y +CONFIG_DEBUG_KERNEL=y +CONFIG_DEBUG_SHIRQ=y +CONFIG_DETECT_SOFTLOCKUP=y +CONFIG_DEBUG_SLAB=y +CONFIG_DEBUG_SLAB_LEAK=y +CONFIG_DEBUG_PREEMPT=y +CONFIG_DEBUG_RT_MUTEXES=y +CONFIG_DEBUG_PI_LIST=y +CONFIG_RT_MUTEX_TESTER=y +CONFIG_DEBUG_SPINLOCK=y +CONFIG_DEBUG_MUTEXES=y +CONFIG_DEBUG_LOCK_ALLOC=y +CONFIG_PROVE_LOCKING=y +CONFIG_LOCKDEP=y +CONFIG_TRACE_IRQFLAGS=y +CONFIG_DEBUG_SPINLOCK_SLEEP=y +CONFIG_DEBUG_LOCKING_API_SELFTESTS=y +CONFIG_STACKTRACE=y +CONFIG_PREEMPT_TRACE=y +CONFIG_DEBUG_BUGVERBOSE=y +CONFIG_DEBUG_INFO=y +CONFIG_FRAME_POINTER=y +CONFIG_FORCED_INLINING=y +CONFIG_DEBUG_STACKOVERFLOW=y +CONFIG_DEBUG_RODATA=y +CONFIG_4KSTACKS=y I've enabled the serial console, and used SysRq to bump the console level to 9 (I want everything, even KERN_DEBUG output). I've enabled the IO-APIC watchdog (nmi_watchdog=1). Once the system locks up, I get no output, no panic, no oops. The serial console is frozen, my ssh sessions are frozen. Suppose the PCI bus crashes (whatever that means) or locks up. Would that make the system completely unresponsive? The I/O does have to get to/from the south bridge, through the PCI bus AFAIU. I can imagine that a locked PCI bus would be slightly problematic. Does this mean I need some kind of PCI bus analyzer (i.e. hardware) at this point? Is there anything more I can try? I've tested with a vanilla 2.6.22.10 kernel (no PREEMPT_RT patch). That system also locks up and remains completely unresponsive (I can't open new ssh sessions, the system won't answer ICMP echo requests). How do driver writers deal with complete kernel hangs? Regards. - To unsubscribe from this list: send the line unsubscribe linux-rt-users in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How to debug complete kernel lock-ups
On Wed, Oct 24, 2007 at 11:17:40AM +0200, John Sigler wrote: John Sigler wrote: I have an x86 system with two PCI slots, in which I inserted two specialized output cards (Dektec DTA-105). http://www.dektec.com/Products/DTA-105/ (They provide an open source driver.) My problem is: when I write to the 4 ports (each card has 2 ports) at the same time (not really at the same time because I have a uni-processor system, so within a short time frame is more accurate) the system *completely* locks up. The manufacturer told me they had seen the problem in their lab. I'm just trying to provide some helpful debug output to speed up the process of fixing the problem :-) I've built a debug 2.6.22.1-rt9 kernel, hoping to get the kernel to dump something, anything. +CONFIG_KALLSYMS_ALL=y +CONFIG_PCI_DEBUG=y +CONFIG_DEBUG_DRIVER=y +CONFIG_PRINTK_TIME=y +CONFIG_MAGIC_SYSRQ=y +CONFIG_DEBUG_KERNEL=y +CONFIG_DEBUG_SHIRQ=y +CONFIG_DETECT_SOFTLOCKUP=y +CONFIG_DEBUG_SLAB=y +CONFIG_DEBUG_SLAB_LEAK=y +CONFIG_DEBUG_PREEMPT=y +CONFIG_DEBUG_RT_MUTEXES=y +CONFIG_DEBUG_PI_LIST=y +CONFIG_RT_MUTEX_TESTER=y +CONFIG_DEBUG_SPINLOCK=y +CONFIG_DEBUG_MUTEXES=y +CONFIG_DEBUG_LOCK_ALLOC=y +CONFIG_PROVE_LOCKING=y +CONFIG_LOCKDEP=y +CONFIG_TRACE_IRQFLAGS=y +CONFIG_DEBUG_SPINLOCK_SLEEP=y +CONFIG_DEBUG_LOCKING_API_SELFTESTS=y +CONFIG_STACKTRACE=y +CONFIG_PREEMPT_TRACE=y +CONFIG_DEBUG_BUGVERBOSE=y +CONFIG_DEBUG_INFO=y +CONFIG_FRAME_POINTER=y +CONFIG_FORCED_INLINING=y +CONFIG_DEBUG_STACKOVERFLOW=y +CONFIG_DEBUG_RODATA=y +CONFIG_4KSTACKS=y I've enabled the serial console, and used SysRq to bump the console level to 9 (I want everything, even KERN_DEBUG output). I've enabled the IO-APIC watchdog (nmi_watchdog=1). Once the system locks up, I get no output, no panic, no oops. The serial console is frozen, my ssh sessions are frozen. Suppose the PCI bus crashes (whatever that means) or locks up. Would that make the system completely unresponsive? The I/O does have to get to/from the south bridge, through the PCI bus AFAIU. I can imagine that a locked PCI bus would be slightly problematic. Does this mean I need some kind of PCI bus analyzer (i.e. hardware) at this point? Is there anything more I can try? I've tested with a vanilla 2.6.22.10 kernel (no PREEMPT_RT patch). That system also locks up and remains completely unresponsive (I can't open new ssh sessions, the system won't answer ICMP echo requests). How do driver writers deal with complete kernel hangs? We slowly go crazy :) Seriously, try to add debugging messages for where you think things might be dying and slowly start working from there. It's not a quick thing to do at times... Oh, try using kdb, that sometimes will work for people, depending on your hardware and problem. good luck, greg k-h - To unsubscribe from this list: send the line unsubscribe linux-rt-users in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How to debug complete kernel lock-ups
On 10/24/07, John Sigler [EMAIL PROTECTED] wrote: I have an x86 system with two PCI slots, in which I inserted two specialized output cards (Dektec DTA-105). http://www.dektec.com/Products/DTA-105/ (They provide an open source driver.) My problem is: when I write to the 4 ports (each card has 2 ports) at the same time (not really at the same time because I have a uni-processor system, so within a short time frame is more accurate) the system *completely* locks up. The manufacturer told me they had seen the problem in their lab. I'm just trying to provide some helpful debug output to speed up the process of fixing the problem :-) [...] Suppose the PCI bus crashes (whatever that means) or locks up. Would that make the system completely unresponsive? The I/O does have to get to/from the south bridge, through the PCI bus AFAIU. I can imagine that a locked PCI bus would be slightly problematic. Does this mean I need some kind of PCI bus analyzer (i.e. hardware) at this point? Is there anything more I can try? You need visibility into the actual place where the issue is happening, and by your description it's the two cards fighting each other on the PCI bus. (I'm assuming that the problem doesn't occur when there's only one card.) I've worked on a platform where only a few things went through the PCI bus, and via the firmware's debugger (completely outside the kernel), I was able to do the setup of the PCI chip and mappings, and then pound on the hardware directly to exhibit a lockup of the bus. That provided pretty strong proof that it wasn't some other unrelated issue in the kernel causing us grief. At that point, it was pretty clear that was it, as there was no kernel running, and the CPU was still responsive. Renting a logic analyzer was the next step. How do driver writers deal with complete kernel hangs? Lots of sleeps in between each and every write to the hardware, with regular output. Of course, if it's a timing issue (which is what it sounds like), you're screwed. Other than that, I look at the hardware guys and say Your turn, and walk out of the room to get a cup of coffee. Ray - To unsubscribe from this list: send the line unsubscribe linux-rt-users in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
How to debug complete kernel lock-ups
Hello everyone, I have an x86 system with two PCI slots, in which I inserted two specialized output cards (Dektec DTA-105). http://www.dektec.com/Products/DTA-105/ (They provide an open source driver.) My problem is: when I write to the 4 ports (each card has 2 ports) at the same time (not really at the same time because I have a uni-processor system, so within a short time frame is more accurate) the system *completely* locks up. The manufacturer told me they had seen the problem in their lab. I'm just trying to provide some helpful debug output to speed up the process of fixing the problem :-) I've built a debug 2.6.22.1-rt9 kernel, hoping to get the kernel to dump something, anything. +CONFIG_KALLSYMS_ALL=y +CONFIG_PCI_DEBUG=y +CONFIG_DEBUG_DRIVER=y +CONFIG_PRINTK_TIME=y +CONFIG_MAGIC_SYSRQ=y +CONFIG_DEBUG_KERNEL=y +CONFIG_DEBUG_SHIRQ=y +CONFIG_DETECT_SOFTLOCKUP=y +CONFIG_DEBUG_SLAB=y +CONFIG_DEBUG_SLAB_LEAK=y +CONFIG_DEBUG_PREEMPT=y +CONFIG_DEBUG_RT_MUTEXES=y +CONFIG_DEBUG_PI_LIST=y +CONFIG_RT_MUTEX_TESTER=y +CONFIG_DEBUG_SPINLOCK=y +CONFIG_DEBUG_MUTEXES=y +CONFIG_DEBUG_LOCK_ALLOC=y +CONFIG_PROVE_LOCKING=y +CONFIG_LOCKDEP=y +CONFIG_TRACE_IRQFLAGS=y +CONFIG_DEBUG_SPINLOCK_SLEEP=y +CONFIG_DEBUG_LOCKING_API_SELFTESTS=y +CONFIG_STACKTRACE=y +CONFIG_PREEMPT_TRACE=y +CONFIG_DEBUG_BUGVERBOSE=y +CONFIG_DEBUG_INFO=y +CONFIG_FRAME_POINTER=y +CONFIG_FORCED_INLINING=y +CONFIG_DEBUG_STACKOVERFLOW=y +CONFIG_DEBUG_RODATA=y +CONFIG_4KSTACKS=y I've enabled the serial console, and used SysRq to bump the console level to 9 (I want everything, even KERN_DEBUG output). I've enabled the IO-APIC watchdog (nmi_watchdog=1). Once the system locks up, I get no output, no panic, no oops. The serial console is frozen, my ssh sessions are frozen. Suppose the PCI bus crashes (whatever that means) or locks up. Would that make the system completely unresponsive? The I/O does have to get to/from the south bridge, through the PCI bus AFAIU. I can imagine that a locked PCI bus would be slightly problematic. Does this mean I need some kind of PCI bus analyzer (i.e. hardware) at this point? Is there anything more I can try? Regards. - To unsubscribe from this list: send the line unsubscribe linux-rt-users in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
