Hi Burak, it would be good to have more information, how this bug can be triggered: * what is the hardware, * can it be reproduced in the same manner on other hardware, * with which configuration (.config file), * does it only happen with CCID 3? Here it is good to know whether - Tickless System (CONFIG_NO_HZ) or - High-resolution timers (CONFIG_HIGH_RES_TIMERS) are enabled, * enabling kernel debugging features (below). Further - are you running DCCP in a virtualised environment? I checked some of the functions below: "default_spin_lock_flags" is defined in arch/x86/kernel/paravirt-spinlocks.c. When running a network protocol that is designed for longer distance networks, some underlying assumptions may no longer hold in the same way as designed. | BTW, how to print EIP after the panic? It needs to be enabled in the kernel configuration. Please enable 1/ "General setup" -> "BUG() support" (CONFIG_BUG=y) 2/ "Kernel hacking" -> "Kernel debugging" (CONFIG_DEBUG_KERNEL=y) 3/ "Kernel hacking" (depends on (2) -> "Verbose BUG() reporting (adds 70k)" (CONFIG_DEBUG_BUGVERBOSE=y) 4/ When enabling (2), it also can not harm to enable the | The console output of the latest panic is as follows: | | [<>] ? ccid3_hc_tx_no_feedback_timer | [<>] ? default_spin_lock_flags | [<>] ? elv_queue_empty | [<>] ? blk_run_queue | [<>] ? kobject_put | [<>] ? trace_hardirqs_off_thunk | [<>] error_code | [<>] ? __mode_timer | [<>] ? do_invalid_op | [<>] ? ccid3_hc_tx_no_feedback_timer | [<>] run_timer_softirq | [<>] ? ccid3_hc_tx_no_feedback_timer | [<>] ? ccid3_hc_tx_no_feedback_timer | [<>] __do_softirq | [<>] ? __do_softirq | <IRQ> [<>] ? irq_exit | [<>] ? smp_apic_timer_interrupt | [<>] ? apic_timer_interrupt | [<>] ? native_safe_halt | [<>] ? default_idle | [<>] ? cpu_idle | [<>] ? rest_init | [<>] ? start_kernel | [<>] ? i386_start_kernel -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html