Hello, On Wed, Nov 02, 2011 at 12:03:39PM +0530, trisha yad wrote: > In loaded embedded system the time at with code hit do_user_fault() > and core_dump_wait() is bit > high, I check on my system it took 2.7 sec. so it is very much > possible that core dump is not correct. This may sound like arguing over semantics but it doesn't matter how long it takes, it's still correct. You're arguing that it's not immediate enough. IOW, no matter how fast you make it, you cannot guarantee that results from slow operation wouldn't appear. Also, the time between do_user_fault() and actual core dumping isn't the important factor here. do_user_fault() directly triggers delivery of SIGSEGV (or BUS) and signal delivery will immediately deliver SIGKILL to all other threads in the process, so it should be immediate enough, or, rather, we don't have any way to make it any more immediate. It's basically direct call + IPI (if some threads are running on other cpus). Are you actually seeing artifacts from delayed core dump? Given the code path, I'm highly skeptical that would be the actual case. If you're using shared memory between different processes, then that delay would matter but for such cases there's nothing much to do. Thanks. -- tejun
