linux-kernel - Re: [PATCH 2/5] efibc: Fix excessive stack footprint warning

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Date:	Tue, 10 May 2016 10:40:22 +0200
From:	jeremy.compostella@...el.com (Compostella, Jeremy)
To:	"Elliott\, Robert \(Persistent Memory\)" <elliott@....com>
Cc:	Matt Fleming <matt@...eblueprint.co.uk>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H . Peter Anvin" <hpa@...or.com>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-efi\@vger.kernel.org" <linux-efi@...r.kernel.org>,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH 2/5] efibc: Fix excessive stack footprint warning

Why not.  See patch as attachment.

Thanks,

Jérémy


View attachment "0001-efibc-report-the-EFI-variable-name-in-the-error-mess.patch" of type "text/x-diff" (1247 bytes)



"Elliott, Robert (Persistent Memory)" <elliott@....com> writes:

>> -----Original Message-----
>> From: linux-kernel-owner@...r.kernel.org [mailto:linux-kernel-
>> owner@...r.kernel.org] On Behalf Of Matt Fleming
>> Sent: Friday, May 06, 2016 4:39 PM
> ...
>> Subject: [PATCH 2/5] efibc: Fix excessive stack footprint warning
>>
>> From: Jeremy Compostella <jeremy.compostella@...el.com>
>>
> ...
>>
>> -static void efibc_set_variable(const char *name, const char *value)
>> +static int efibc_set_variable(const char *name, const char *value)
>>  {
>>       int ret;
>>       efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
>> -     struct efivar_entry entry;
>> +     struct efivar_entry *entry;
>>       size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
>>
>> -     if (size > sizeof(entry.var.Data))
>> +     if (size > sizeof(entry->var.Data)) {
>>               pr_err("value is too large");
>
> That pr_err is introduced by patch 25/40 of the first series.
>
> How about including the name of the variable for which this is failing,
> like the final pr_err?
>
>> +             return -EINVAL;
>> +     }
>>
>> -     efibc_str_to_str16(name, entry.var.VariableName);
>> -     efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data);
>> -     memcpy(&entry.var.VendorGuid, &guid, sizeof(guid));
>> +     entry = kmalloc(sizeof(*entry), GFP_KERNEL);
>> +     if (!entry) {
>> +             pr_err("failed to allocate efivar entry");
>
> How about including the name of the variable for which this
> is failing, like the final pr_err?
>
>> +             return -ENOMEM;
>> +     }
>>
>> -     ret = efivar_entry_set(&entry,
>> +     efibc_str_to_str16(name, entry->var.VariableName);
>> +     efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
>> +     memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
>> +
>> +     ret = efivar_entry_set(entry,
>>                              EFI_VARIABLE_NON_VOLATILE
>>                              | EFI_VARIABLE_BOOTSERVICE_ACCESS
>>                              | EFI_VARIABLE_RUNTIME_ACCESS,
>> -                            size, entry.var.Data, NULL);
>> +                            size, entry->var.Data, NULL);
>>       if (ret)
>>               pr_err("failed to set %s EFI variable: 0x%x\n",
>>                      name, ret);
>> +
>> +     kfree(entry);
>> +     return ret;
>>  }
>

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