From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: linux-next: build warnings after merge of the block tree
Date: Fri, 16 Jun 2023 14:43:54 +0200 [thread overview]
Message-ID: <20230616124354.GD4253@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230412162517.gji52t34zlvcu5bh@treble>
On Wed, Apr 12, 2023 at 09:25:17AM -0700, Josh Poimboeuf wrote:
> From: Josh Poimboeuf <jpoimboe@kernel.org>
> Subject: [PATCH] iov_iter: Mark copy_compat_iovec_from_user() noinline
>
> After commit 6376ce56feb6 ("iov_iter: import single vector iovecs as
> ITER_UBUF"), GCC does an inter-procedural compiler optimization which
> moves the user_access_begin() out of copy_compat_iovec_from_user() and
> into its callers:
>
> lib/iov_iter.o: warning: objtool: .altinstr_replacement+0x0: redundant UACCESS disable
> lib/iov_iter.o: warning: objtool: iovec_from_user.part.0+0xc7: call to copy_compat_iovec_from_user.part.0() with UACCESS enabled
> lib/iov_iter.o: warning: objtool: __import_iovec+0x21d: call to copy_compat_iovec_from_user.part.0() with UACCESS enabled
>
> Enforce the "no UACCESS enable across function boundaries" rule by
> disabling cloning for copy_compat_iovec_from_user().
>
> Fixes: 6376ce56feb6 ("iov_iter: import single vector iovecs as ITER_UBUF")
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> https://lkml.kernel.org/lkml/20230327120017.6bb826d7@canb.auug.org.au
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
> ---
> lib/iov_iter.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
> index 274014e4eafe..48aa9fd99267 100644
> --- a/lib/iov_iter.c
> +++ b/lib/iov_iter.c
> @@ -1698,7 +1698,7 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
> }
> EXPORT_SYMBOL(dup_iter);
>
> -static int copy_compat_iovec_from_user(struct iovec *iov,
> +static __noclone int copy_compat_iovec_from_user(struct iovec *iov,
> const struct iovec __user *uvec, unsigned long nr_segs)
> {
> const struct compat_iovec __user *uiov =
I've been getting reports from some anonymous people still using ancient
GCCs (10.4) that also need the following:
---
Subject: iov_iter: Mark copy_iovec_from_user() noclone
Extend commit 50f9a76ef127 ("iov_iter: Mark
copy_compat_iovec_from_user() noinline") to also cover
copy_iovec_from_user(). Different compiler versions cause the same
problem on different functions.
lib/iov_iter.o: warning: objtool: .altinstr_replacement+0x1f: redundant UACCESS disable
lib/iov_iter.o: warning: objtool: iovec_from_user+0x84: call to copy_iovec_from_user.part.0() with UACCESS enabled
lib/iov_iter.o: warning: objtool: __import_iovec+0x143: call to copy_iovec_from_user.part.0() with UACCESS enabled
Fixes: 50f9a76ef127 ("iov_iter: Mark copy_compat_iovec_from_user() noinline")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 960223ed9199..061cc3ed58f5 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1795,7 +1795,7 @@ static __noclone int copy_compat_iovec_from_user(struct iovec *iov,
return ret;
}
-static int copy_iovec_from_user(struct iovec *iov,
+static __noclone int copy_iovec_from_user(struct iovec *iov,
const struct iovec __user *uiov, unsigned long nr_segs)
{
int ret = -EFAULT;
next prev parent reply other threads:[~2023-06-16 12:45 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 1:00 linux-next: build warnings after merge of the block tree Stephen Rothwell
2023-03-27 16:26 ` Josh Poimboeuf
2023-03-27 23:47 ` Stephen Rothwell
2023-04-11 21:34 ` Stephen Rothwell
2023-04-11 21:55 ` Josh Poimboeuf
2023-04-11 22:39 ` Jens Axboe
2023-04-12 0:14 ` Josh Poimboeuf
2023-04-12 1:48 ` Jens Axboe
2023-04-12 11:44 ` Peter Zijlstra
2023-04-12 16:25 ` Josh Poimboeuf
2023-04-12 16:35 ` Jens Axboe
2023-04-12 16:44 ` Jens Axboe
2023-04-12 16:56 ` Josh Poimboeuf
2023-04-12 17:57 ` Jens Axboe
2023-06-16 12:43 ` Peter Zijlstra [this message]
2023-06-16 12:49 ` Borislav Petkov
2023-07-03 11:04 ` Peter Zijlstra
2023-07-03 14:18 ` Jens Axboe
2023-07-03 15:14 ` Peter Zijlstra
2023-04-11 22:30 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2024-02-06 2:10 Stephen Rothwell
2024-02-06 4:13 ` Stephen Rothwell
2024-02-06 11:12 ` Geert Uytterhoeven
2024-02-06 13:42 ` Geert Uytterhoeven
2024-02-06 14:53 ` Jens Axboe
2024-02-06 14:49 ` Jens Axboe
2023-07-27 6:10 Stephen Rothwell
2023-07-27 12:41 ` Jens Axboe
2022-07-15 11:51 Stephen Rothwell
2020-03-03 1:41 Stephen Rothwell
2020-03-03 2:59 ` Jens Axboe
2018-03-01 0:26 Stephen Rothwell
2018-03-01 4:02 ` Anshuman Khandual
2018-03-01 15:37 ` Jens Axboe
2013-11-26 2:29 Stephen Rothwell
2013-11-26 3:35 ` Stephen Rothwell
2013-11-26 19:01 ` Olof Johansson
2013-11-26 19:02 ` Jens Axboe
2011-01-07 0:02 Stephen Rothwell
2011-01-07 1:49 ` Mathieu Desnoyers
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