Hello Kees,
On Mon, May 14, 2012 at 03:21:17PM -0700, Kees Cook wrote: [...]
- buf = cxt->virt_addr + (id * cxt->record_size);
- memset(buf, '\0', cxt->record_size);
- persistent_ram_free_old(cxt->przs[id]);
Hm, I don't think persistent_ram_free_old() is what's wanted here. That appears to entirely release the region? I want to make sure the memory is cleared first. And will this area come back on a write, or does it stay released?
It just releases ECC-restored memory region (a copy). The original (persistent) region is still fully reusable after that call.
(It is a pity that pstore internals can't use the restored copy directly, as pstore expects that it will release the region itself after pstore_mkfile(), so we somewhat duplicate the memory during psi->read(). We'd better fix it some day, but it's a minor issue so far.)
return 0; } @@ -200,6 +203,7 @@ static int __init ramoops_probe(struct platform_device *pdev) struct ramoops_platform_data *pdata = pdev->dev.platform_data; struct ramoops_context *cxt = &oops_cxt; int err = -EINVAL;
- int i;
/* Only a single ramoops area allowed at a time, so fail extra * probes. @@ -237,32 +241,37 @@ static int __init ramoops_probe(struct platform_device *pdev) cxt->record_size = pdata->record_size; cxt->dump_oops = pdata->dump_oops;
- cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_count, GFP_KERNEL);
- if (!cxt->przs) {
- pr_err("failed to initialize a prz array\n");
- goto fail_przs;
This should be fail_out.
Thanks, will fix all of these error handling negligences.
- }
- for (i = 0; i < cxt->max_count; i++) {
- size_t sz = cxt->record_size;
- phys_addr_t start = cxt->phys_addr + sz * i;
- cxt->przs[i] = persistent_ram_new(start, sz, 0);
persistent_ram_new() is marked as __init, so this is unsafe to call if built as a module. I think persistent_ram_new() will need to lose the __init marking, or I'm misunderstanding something.
Um. ramoops' probe routine is also __init. persistent_ram_new is a part of ramoops module, so their __init functions will be discarded at the same time.
ram_console can't be a module, so it is also fine.
So I think it's all fine.
- if (IS_ERR(cxt->przs[i])) {
- err = PTR_ERR(cxt->przs[i]);
- pr_err("failed to initialize a prz\n");
Since neither persistent_ram_new() nor persistent_ram_buffer_map() report the location of the failure, I'd like to keep the error report (removed below "pr_err("request mem region (0x%lx@0x%llx) failed\n",...") for failures, so there is something actionable in dmesg when the platform data is mismatched for the hardware.
Sure thing, will do. I'll also start using dev_err() for new code, that way it's more clearer which module reported the error.
[...]
cxt->pstore.data = cxt;
- cxt->pstore.bufsize = cxt->record_size;
- cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
spin_lock_init(&cxt->pstore.buf_lock);
- cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
- cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
I don't see a reason to re-order these (nothing can use buf yet because we haven't registered it with pstore yet).
Yeah, this is a left over. Thank for catching.
[...]
+fail_przs:
- for (i = 0; cxt->przs[i]; i++)
- persistent_ram_free(cxt->przs[i]);
This can lead to a BUG, since persistent_ram_free() doesn't handle NULL arguments.
The for loop has 'cxt->przs[i]' condition. :-)
Thanks for the review!