Messages in this thread | | | Date | Wed, 15 Dec 2010 10:04:37 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC] [Patch 0/21] Non disruptive application core dump infrastructure |
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On Tue, 14 Dec 2010 15:22:59 +0530 "Suzuki K. Poulose" <suzuki@in.ibm.com> wrote:
> Hi all, > > This is series of patches implementing an infrastructure for capturing the core > of an application without disrupting its process semantics. > > The infrastructure makes use of the freezer subsystem in kernel to freeze the > threads and then collect the information to generate the core. > > The interface is provided by a /proc/pid/core file, reading which can give the > ELF formatted core of the process with "pid". The interface supports "seek" > operation on the fd, allowing the dumper to have control on the data that is > being dumped. Also it allows the user to store the dump at any location. > > The current implementation supports both native as well as the compat ELF > tasks. > > An open() call to the /proc/pid/core will try to freeze the threads in the > process and the read() requests will dynamically generate the contents for the > core file. The ELF header & Program Headers are stored in a kernel buffer to > allow us to map the fpos to the required data section. > > In case a thread is not frozen within a time interval, after issuing the freeze > request, we fill the register state information with 0's to indicate we could > not capture the data. > > A close() would kick the threads out of the refrigerator(). > > > The implementation reuses some of the existing ELF core generation code by > exporting them. Some of the code common to both native and compat ELF class > support has been moved to a common place, elfcore-common.c. Also some of the > reusable functions, specific to the ELF class handling, has been made global, > after renaming the compat version of the same. > > We also added a new API -elf_core_copy_extra_phdrs() -for "reading" the arch > specific program headers, versus the existing elf_core_write_extra_phdrs(). > > Patches 1 to 9 deals with re-arranging the ELF code to be reusable by the > infrastructure. > > Patches 10 to 21 implements the infrastructure. > > TODO: Add support for collecting the arch specific notes, currently used only > by Cell platform. > > Please let me know your review comments / thoughts. >
Your purpose of this patch is to debug an application without attaching to gdb or take coredump by gcore ?
IIUC, "freeze" is a bit dangerous because no one can ends the application while it's freezed and there is no information "it's frozen" via usaual user commands as 'ps' or 'top'.
Can you add a new freeze state where the application can get SIGKILL, at least ? and show task's state as "frozen" in some way ? as task_state_array[] shows it in /proc/<pid>/status
Thanks, -Kame
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