From: Josh Poimboeuf Date: Wed, 12 Apr 2023 16:46:48 +0000 (-0600) Subject: iov_iter: Mark copy_compat_iovec_from_user() noinline X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=50f9a76ef127;p=linux.git 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 https://lkml.kernel.org/lkml/20230327120017.6bb826d7@canb.auug.org.au Signed-off-by: Josh Poimboeuf Tested-by: Jens Axboe Signed-off-by: Jens Axboe --- diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 3e6c9bcfa612c..86a066aa9bcc9 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1702,7 +1702,7 @@ 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 =