From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH] kdev_t: Always inline major/minor helper functions
Date: Mon, 4 Jan 2021 13:28:25 +0100 [thread overview]
Message-ID: <20210104122825.GM3021@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <984353b44a4484d86ba9f73884b7306232e25e30.1608737428.git.jpoimboe@redhat.com>
On Wed, Dec 23, 2020 at 09:30:48AM -0600, Josh Poimboeuf wrote:
> Silly GCC doesn't always inline these trivial functions.
>
> Fixes the following warning:
>
> arch/x86/kernel/sys_ia32.o: warning: objtool: cp_stat64()+0xd8: call to new_encode_dev() with UACCESS enabled
>
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
The alternative is something like:
diff --git a/arch/x86/kernel/sys_ia32.c b/arch/x86/kernel/sys_ia32.c
index 6cf65397d225..6ca3da08dbcb 100644
--- a/arch/x86/kernel/sys_ia32.c
+++ b/arch/x86/kernel/sys_ia32.c
@@ -133,18 +133,23 @@ static int cp_stat64(struct stat64 __user *ubuf, struct kstat *stat)
{
typeof(ubuf->st_uid) uid = 0;
typeof(ubuf->st_gid) gid = 0;
+ u64 dev, rdev;
+
SET_UID(uid, from_kuid_munged(current_user_ns(), stat->uid));
SET_GID(gid, from_kgid_munged(current_user_ns(), stat->gid));
+ dev = huge_encode_dev(stat->dev);
+ rdev = huge_encode_dev(stat->rdev);
+
if (!user_write_access_begin(ubuf, sizeof(struct stat64)))
return -EFAULT;
- unsafe_put_user(huge_encode_dev(stat->dev), &ubuf->st_dev, Efault);
+ unsafe_put_user(dev, &ubuf->st_dev, Efault);
unsafe_put_user(stat->ino, &ubuf->__st_ino, Efault);
unsafe_put_user(stat->ino, &ubuf->st_ino, Efault);
unsafe_put_user(stat->mode, &ubuf->st_mode, Efault);
unsafe_put_user(stat->nlink, &ubuf->st_nlink, Efault);
unsafe_put_user(uid, &ubuf->st_uid, Efault);
unsafe_put_user(gid, &ubuf->st_gid, Efault);
- unsafe_put_user(huge_encode_dev(stat->rdev), &ubuf->st_rdev, Efault);
+ unsafe_put_user(rdev, &ubuf->st_rdev, Efault);
unsafe_put_user(stat->size, &ubuf->st_size, Efault);
unsafe_put_user(stat->atime.tv_sec, &ubuf->st_atime, Efault);
unsafe_put_user(stat->atime.tv_nsec, &ubuf->st_atime_nsec, Efault);
next prev parent reply other threads:[~2021-01-04 12:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 15:30 [PATCH] kdev_t: Always inline major/minor helper functions Josh Poimboeuf
2020-12-23 18:06 ` Randy Dunlap
2021-01-04 12:28 ` Peter Zijlstra [this message]
2021-01-04 15:31 ` Josh Poimboeuf
2021-01-04 15:53 ` [PATCH] x86/compat: Pull huge_encode_dev() outside of UACCESS Peter Zijlstra
2021-01-04 16:19 ` Randy Dunlap
2021-01-04 17:24 ` Josh Poimboeuf
2021-01-04 23:14 ` Josh Poimboeuf
2021-01-04 23:55 ` Randy Dunlap
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