[PATCH] module: do not print allocation-fail warning on bogus user buffer size

[PATCH] module: do not print allocation-fail warning on bogus user buffer size

[Kirill A. Shutemov]

init_module(2) passes user-specified buffer length directly to
vmalloc(). It makes warn_alloc_failed() to print out a lot of info into
dmesg if user specified insane size, like -1.

Let's silence the warning. It doesn't add much value to -ENOMEM return
code. Without the patch the syscall is prohibitive noisy for testing
with trinity.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Sasha Levin <sasha.levin@oracle.com>
---
 kernel/module.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index b34813f725e9..f63e5e8f3385 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2494,7 +2494,8 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 		return err;
 
 	/* Suck in entire file: we'll want most of it. */
-	info->hdr = vmalloc(info->len);
+	info->hdr = __vmalloc(info->len,
+			GFP_KERNEL | __GFP_HIGHMEM | __GFP_NOWARN, PAGE_KERNEL);
 	if (!info->hdr)
 		return -ENOMEM;
 
-- 
2.1.4

Re: [PATCH] module: do not print allocation-fail warning on bogus user buffer size

[Rusty Russell]

"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes:
> init_module(2) passes user-specified buffer length directly to
> vmalloc(). It makes warn_alloc_failed() to print out a lot of info into
> dmesg if user specified insane size, like -1.
>
> Let's silence the warning. It doesn't add much value to -ENOMEM return
> code. Without the patch the syscall is prohibitive noisy for testing
> with trinity.

Heh, we used to have an explicit length check because vmalloc would
BUG().  So I guess this is progress...

Applied thanks,
Rusty.