I'm not sure if this is the place for this, but: I have an x86_64 machine that gets an immediate SIGSEGV when ptracing anything:
[r...@dl360g6gs1 kernel-2.6.18]# strace true execve("/bin/true", ["true"], [/* 28 vars */]) = 0 --- SIGSEGV (Segmentation fault) @ 0 (0) --- +++ killed by SIGSEGV +++ I have recompiled the kernel (2.6.18-128.7.1.el5), but the only significant change I can think of making is that I enabled preemption. I also have an x86_64 VM under VirtualBox using a slightly different kernel. It was initially working, but when I installed an updated kernel RPM, it started crashing as well -- even before rebooting into the new kernel! However, it is crashing differently. It gives me a kernel stack trace (pasted below). It looks like some sort of locking issue. Is this problem fixed in later patched kernels? I know kernel-2.6.18-164.11.1.el5.x86_64.rpm is available, but the last time I tried that particular one it caused me some unrelated problems so I'm hesitant to go there. I can post the kernel config if it would be helpful. ---- BUG: warning at kernel/ptrace.c:1674/ptrace_report() (Not tainted) Call Trace: [<ffffffff800c44d4>] ptrace_report+0xeb/0x120 [<ffffffff800c3f52>] utrace_report_syscall+0x74/0x227 [<ffffffff80070f41>] syscall_trace_leave+0x5e/0x87 [<ffffffff80060312>] int_very_careful+0x35/0x3f BUG: scheduling while atomic: true/0x00000001/2526 Call Trace: [<ffffffff800655dd>] __sched_text_start+0x7d/0xc22 [<ffffffff800a0484>] kernel_text_address+0x1a/0x26 [<ffffffff8006f17b>] dump_trace+0x214/0x23d [<ffffffff800c2212>] utrace_quiescent+0xde/0x261 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff80070f41>] syscall_trace_leave+0x5e/0x87 [<ffffffff80060312>] int_very_careful+0x35/0x3f BUG: warning at kernel/ptrace.c:1674/ptrace_report() (Not tainted) Call Trace: [<ffffffff800c44d4>] ptrace_report+0xeb/0x120 [<ffffffff80060312>] int_very_careful+0x35/0x3f [<ffffffff800c45ea>] ptrace_report_signal+0x4c/0x5c [<ffffffff800c1955>] report_signal+0x7f/0x179 [<ffffffff800c3282>] utrace_get_signal+0x3e3/0x62b [<ffffffff8006e73c>] __switch_to+0x2e/0x22d [<ffffffff8002c12a>] get_signal_to_deliver+0x177/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff8006032e>] int_signal+0x12/0x17 BUG: scheduling while atomic: true/0x00000001/2526 Call Trace: [<ffffffff800655dd>] __sched_text_start+0x7d/0xc22 [<ffffffff800c44ec>] ptrace_report+0x103/0x120 [<ffffffff80060312>] int_very_careful+0x35/0x3f [<ffffffff800c45ea>] ptrace_report_signal+0x4c/0x5c [<ffffffff800c1955>] report_signal+0x7f/0x179 [<ffffffff800c2212>] utrace_quiescent+0xde/0x261 [<ffffffff800c3450>] utrace_get_signal+0x5b1/0x62b [<ffffffff8006e73c>] __switch_to+0x2e/0x22d [<ffffffff8002c12a>] get_signal_to_deliver+0x177/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff8006032e>] int_signal+0x12/0x17 Call Trace: [<ffffffff800655dd>] __sched_text_start+0x7d/0xc22 [<ffffffff800c44ec>] ptrace_report+0x103/0x120 [<ffffffff80060312>] int_very_careful+0x35/0x3f [<ffffffff800c45ea>] ptrace_report_signal+0x4c/0x5c [<ffffffff800c1955>] report_signal+0x7f/0x179 [<ffffffff800c2212>] utrace_quiescent+0xde/0x261 [<ffffffff800c3450>] utrace_get_signal+0x5b1/0x62b [<ffffffff8006e73c>] __switch_to+0x2e/0x22d [<ffffffff8002c12a>] get_signal_to_deliver+0x177/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff8006032e>] int_signal+0x12/0x17 BUG: warning at kernel/ptrace.c:1674/ptrace_report() (Not tainted) Call Trace: [<ffffffff800c44d4>] ptrace_report+0xeb/0x120 [<ffffffff800c45ea>] ptrace_report_signal+0x4c/0x5c [<ffffffff800c1955>] report_signal+0x7f/0x179 [<ffffffff800c3282>] utrace_get_signal+0x3e3/0x62b [<ffffffff8002c12a>] get_signal_to_deliver+0x177/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff8009af62>] specific_send_sig_info+0xa1/0xac [<ffffffff800683c9>] _spin_unlock_irqrestore+0x16/0x31 [<ffffffff8009b243>] force_sig_info+0xae/0xb9 [<ffffffff8006a707>] do_page_fault+0x81e/0x830 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff800606e0>] retint_signal+0x3d/0x79 BUG: scheduling while atomic: true/0x00000001/2526 Call Trace: [<ffffffff800655dd>] __sched_text_start+0x7d/0xc22 [<ffffffff800c44ec>] ptrace_report+0x103/0x120 [<ffffffff800c45ea>] ptrace_report_signal+0x4c/0x5c [<ffffffff800c1955>] report_signal+0x7f/0x179 [<ffffffff800c2212>] utrace_quiescent+0xde/0x261 [<ffffffff800c3450>] utrace_get_signal+0x5b1/0x62b [<ffffffff8002c12a>] get_signal_to_deliver+0x177/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff8009af62>] specific_send_sig_info+0xa1/0xac [<ffffffff800683c9>] _spin_unlock_irqrestore+0x16/0x31 [<ffffffff8009b243>] force_sig_info+0xae/0xb9 [<ffffffff8006a707>] do_page_fault+0x81e/0x830 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff800606e0>] retint_signal+0x3d/0x79 BUG: warning at kernel/ptrace.c:562/ptrace_exit() (Not tainted) Call Trace: [<ffffffff800c6780>] ptrace_exit+0x51/0x1f2 [<ffffffff80015d62>] do_exit+0x126/0x9bb [<ffffffff8004b1fd>] cpuset_exit+0x0/0x6c [<ffffffff8002c3e5>] get_signal_to_deliver+0x432/0x461 [<ffffffff8005d4ed>] do_notify_resume+0x9c/0x7b0 [<ffffffff8009af62>] specific_send_sig_info+0xa1/0xac [<ffffffff800683c9>] _spin_unlock_irqrestore+0x16/0x31 [<ffffffff8009b243>] force_sig_info+0xae/0xb9 [<ffffffff8006a707>] do_page_fault+0x81e/0x830 [<ffffffff800c4095>] utrace_report_syscall+0x1b7/0x227 [<ffffffff800606e0>] retint_signal+0x3d/0x79 note: true[2526] exited with preempt_count 1