From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
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 09:31:27 -0600 [thread overview]
Message-ID: <20210104153127.e44uchjhlgg3hq2g@treble> (raw)
In-Reply-To: <20210104122825.GM3021@hirez.programming.kicks-ass.net>
On Mon, Jan 04, 2021 at 01:28:25PM +0100, Peter Zijlstra wrote:
> 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:
I like your approach better, it avoids __always_inline sprawl.
Peter, care to submit a proper patch?
Andrew, can you drop mine?
>
> 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);
>
--
Josh
next prev parent reply other threads:[~2021-01-04 15:33 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
2021-01-04 15:31 ` Josh Poimboeuf [this message]
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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