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copied!<p>I continue to suspect that your customer/user has some kernel module or driver loaded which is interfering with the <code>clone()</code> system call (perhaps some obscure security enhancement, something like LIDS but more obscure?) or is somehow filling up some of the kernel data structures that are necessary for <code>fork()</code>/<code>clone()</code> to operate (process table, page tables, file descriptor tables, etc).</p> <p>Here's the relevant portion of the <code>fork(2)</code> man page:</p> <pre> ERRORS EAGAIN fork() cannot allocate sufficient memory to copy the parent's page tables and allocate a task structure for the child. EAGAIN It was not possible to create a new process because the caller's RLIMIT_NPROC resource limit was encountered. To exceed this limit, the process must have either the CAP_SYS_ADMIN or the CAP_SYS_RESOURCE capability. ENOMEM fork() failed to allocate the necessary kernel structures because memory is tight. </pre> <p>I suggest having the user try this after booting into a stock, generic kernel and with only a minimal set of modules and drivers loaded (minimum necessary to run your application/script). From there, assuming it works in that configuration, they can perform a binary search between that and the configuration which exhibits the issue. This is standard sysadmin troubleshooting 101.</p> <p>The relevant line in your <code>strace</code> is:</p> <pre><code>clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7f12708) = -1 ENOMEM (Cannot allocate memory) </code></pre> <p>... I know others have talked about swap and memory availability (and I would recommend that you set up at least a small swap partition, ironically even if it's on a RAM disk ... the code paths through the Linux kernel when it has even a tiny bit of swap available have been exercised far more extensively than those (exception handling paths) in which there is zero swap available.</p> <p>However I suspect that this is still a red herring.</p> <p>The fact that <code>free</code> is reporting 0 (ZERO) memory in use by the cache and buffers is very disturbing. I suspect that the <code>free</code> output ... and possibly your application issue here, are caused by some proprietary kernel module which is interfering with the memory allocation in some way.</p> <p>According to the man pages for fork()/clone() the fork() system call should return EAGAIN if your call would cause a resource limit violation (RLIMIT_NPROC) ... however, it doesn't say if EAGAIN is to be returned by other RLIMIT* violations. In any event if your target/host has some sort of weird Vormetric or other security settings (or even if your process is running under some weird SELinux policy) then it might be causing this -ENOMEM failure.</p> <p>It's pretty unlikely to be a normal run-of-the-mill Linux/UNIX issue. You've got something non-standard going on there.</p>

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