Messages in this thread Patch in this message | | | Date | Fri, 16 Jun 2023 14:43:54 +0200 | From | Peter Zijlstra <> | Subject | Re: linux-next: build warnings after merge of the block tree |
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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;
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