Commit da48d094ce5d ("Kconfig: remove HAVE_LATENCYTOP_SUPPORT")
allows CONFIG_LATENCYTOP to be selected on all architectures, since
save_stack_trace_tsk is now provided unconditionally by core code.Unfortunately, this results in a build error for ia64 when the option is enabled: arch/ia64/kernel/entry.S: Assembler messages: arch/ia64/kernel/entry.S:621: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) arch/ia64/kernel/entry.S:728: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) arch/ia64/kernel/entry.S:859: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) make[1]: *** [arch/ia64/kernel/entry.o] Error 1 This is because task_struct is now over 8k thanks to the latency_record array, which means that the 14-bit immediate offset expect by the adds instruction to grab hold of the thread info flags is now out-of-range on ia64. Fixing the ia64 entry code without making it less efficient is beyond me, but rather than revert da48d094ce5d entirely, we can simply make LATENCYTOP depend on !IA64 until somebody brave steps up to tackle the entry code over there. Cc: Tony Luck <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Andrew Morton <[email protected]> Reported-by: Al Viro <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- I previously reported this on linux-arch, but the conversation didn't go anywhere: http://marc.info/?l=linux-arch&m=145390684108109 lib/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8bfd1aca7a3d..c8d12808b9aa 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1615,6 +1615,7 @@ config LATENCYTOP depends on DEBUG_KERNEL depends on STACKTRACE_SUPPORT depends on PROC_FS + depends on !IA64 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC select KALLSYMS select KALLSYMS_ALL -- 2.1.4
