6.12-stable patches

added patches:
	kbuild-add-fno-builtin-wcslen.patch

diff --git a/queue-6.12/kbuild-add-fno-builtin-wcslen.patch b/queue-6.12/kbuild-add-fno-builtin-wcslen.patch
new file mode 100644 (file)
index 0000000..06688ec
--- /dev/null
+++ b/queue-6.12/kbuild-add-fno-builtin-wcslen.patch
@@ -0,0 +1,59 @@
+From 99d01048fc148dc10471b67da642df190a9727bb Mon Sep 17 00:00:00 2001
+From: Nathan Chancellor <nathan@kernel.org>
+Date: Mon, 7 Apr 2025 16:22:12 -0700
+Subject: kbuild: Add '-fno-builtin-wcslen'
+
+From: Nathan Chancellor <nathan@kernel.org>
+
+commit 84ffc79bfbf70c779e60218563f2f3ad45288671 upstream.
+
+A recent optimization change in LLVM [1] aims to transform certain loop
+idioms into calls to strlen() or wcslen(). This change transforms the
+first while loop in UniStrcat() into a call to wcslen(), breaking the
+build when UniStrcat() gets inlined into alloc_path_with_tree_prefix():
+
+  ld.lld: error: undefined symbol: wcslen
+  >>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
+  >>>               vmlinux.o:(alloc_path_with_tree_prefix)
+  >>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
+  >>>               vmlinux.o:(alloc_path_with_tree_prefix)
+
+Disable this optimization with '-fno-builtin-wcslen', which prevents the
+compiler from assuming that wcslen() is available in the kernel's C
+library.
+
+[ More to the point - it's not that we couldn't implement wcslen(), it's
+  that this isn't an optimization at all in the context of the kernel.
+
+  Replacing a simple inlined loop with a function call to the same loop
+  is just stupid and pointless if you don't have long strings and fancy
+  libraries with vectorization support etc.
+
+  For the regular 'strlen()' cases, we want the compiler to do this in
+  order to handle the trivial case of constant strings. And we do have
+  optimized versions of 'strlen()' on some architectures. But for
+  wcslen? Just no.    - Linus ]
+
+Cc: stable@vger.kernel.org
+Link: https://github.com/llvm/llvm-project/commit/9694844d7e36fd5e01011ab56b64f27b867aa72d [1]
+Signed-off-by: Nathan Chancellor <nathan@kernel.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+[nathan: Resolve small conflict in older trees]
+Signed-off-by: Nathan Chancellor <nathan@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Makefile |    3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/Makefile
++++ b/Makefile
+@@ -1013,6 +1013,9 @@ ifdef CONFIG_CC_IS_GCC
+ KBUILD_CFLAGS   += -fconserve-stack
+ endif
+ 
++# Ensure compilers do not transform certain loops into calls to wcslen()
++KBUILD_CFLAGS += -fno-builtin-wcslen
++
+ # change __FILE__ to the relative path from the srctree
+ KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
+ 

diff --git a/queue-6.12/series b/queue-6.12/series
index 8015f32ca0e391b24ee2bbc63d5873006d7f943d..5271b595b29178f14283cfb4ed7a5cb7d1c04d7f 100644 (file)
--- a/queue-6.12/series
+++ b/queue-6.12/series
@@ -387,3 +387,4 @@ nfsd-fix-cb_getattr-status-fix.patch
 nfsd-don-t-ignore-the-return-code-of-svc_proc_register.patch
 x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch
 libbpf-prevent-compiler-warnings-errors.patch
+kbuild-add-fno-builtin-wcslen.patch