Re: [Crash-utility] backtrace failure on x86_64 and x86 in 2.6.33/34 kernels due to "thread_return" removal

----- "Dave Anderson" <anderson(a)redhat.com&gt; wrote: As it turns out, the x86 backtrace failures in 2.6.33/34 are caused by a different kprobes-related commit, which moved the system_call assembly function to the .kprobes.text section: commit a00e817f42663941ea0aa5f85a9d1c4f8b212839 Author: Masami Hiramatsu <mhiramat(a)redhat.com&gt; Date: Tue Sep 8 12:47:55 2009 -0400 kprobes/x86-32: Move irq-exit functions to kprobes section Move irq-exit functions to .kprobes.text section to protect against kprobes recursion. When I ran kprobe stress test on x86-32, I found below symbols cause unrecoverable recursive probing: ret_from_exception ret_from_intr check_userspace restore_all restore_all_notrace restore_nocheck irq_return And also, I found some interrupt/exception entry points that cause similar problems. This patch moves those symbols (including their container functions) to .kprobes.text section to prevent any kprobes probing. Signed-off-by: Masami Hiramatsu <mhiramat(a)redhat.com&gt; Cc: Frederic Weisbecker <fweisbec(a)gmail.com&gt; Cc: Ananth N Mavinakayanahalli <ananth(a)in.ibm.com&gt; Cc: Jim Keniston <jkenisto(a)us.ibm.com&gt; Cc: Ingo Molnar <mingo(a)elte.hu&gt; LKML-Reference: <20090908164755.24050.81182.stgit(a)dhcp-100-2-132.bos.redhat.com&gt; Signed-off-by: Frederic Weisbecker <fweisbec(a)gmail.com&gt; ... [ snip ] ... @@ -513,6 +521,10 @@ sysexit_audit: PTGS_TO_GS_EX ENDPROC(ia32_sysenter_target) +/* + * syscall stub including irq exit should be protected against kprobes + */ + .pushsection .kprobes.text, "ax" # system call handler stub ENTRY(system_call) RING0_INT_FRAME # can't unwind into user space anyway @@ -705,6 +717,10 @@ syscall_badsys: jmp resume_userspace END(syscall_badsys) CFI_ENDPROC +/* + * End of kprobes section + */ + .popsection I should have a fix tomorrow (if that's the only issue)... Dave