Messages in this thread | | | Date | Fri, 4 Aug 2006 16:57:11 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH] module interface improvement for kprobes |
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> { > /* grab the module, making sure it won't get unloaded until > * we're done */ > const char *mod_name = "joydev"; > if (module_get_byname(mod_name, &mod) != 0) > return 1; > > /* Specify the address/offset where you want to insert > * probe. If this were a real kprobe module, we'd "relocate" > * our probe address based on the load address of the module > * we're interested in. */ > kp.addr = (kprobe_opcode_t *) mod->module_core + 0; > > /* All set to register with Kprobes */ > register_kprobe(&kp); > return 0; > }
This interface is horrible. You actual patch looks good to me, but it I can't see why you would need it. kallsyms_lookup_name deals with modules transparently and you shouldn't put a probe at a relative offset into a module but only at a symbol you could find with kallsys.
That beeing said we should probably change the kprobes interface to automatically do the kallsysms name lookup for the caller. It would simplify the kprobes interface and allow us to get rid of the kallsyms_lookup_name export that doesn't have a valid use except for kprobes. With that change the example kprobe would look like:
static struct kprobe kp = { .pre_handler = handler_pre, .post_handler = handler_post, .fault_handler = handler_fault, .symbol_name = "do_fork", };
static int __init probe_example_init(void) { return register_kprobe(&kp); }
(and btw, init_module is gone, so both your example and the one in Documentation/kprobes.txt can't compile anymore - care to send a patch to update the latter?) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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