linux-kernel - [tip: x86/build] x86/math-emu: Fix div

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <176272949287.498.1639238092119699825.tip-bot2@tip-bot2>
Date: Sun, 09 Nov 2025 23:04:52 -0000
From: "tip-bot2 for Arnd Bergmann" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Arnd Bergmann <arnd@...db.de>, "Borislav Petkov (AMD)" <bp@...en8.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/build] x86/math-emu: Fix div_Xsig() prototype

The following commit has been merged into the x86/build branch of tip:

Commit-ID:     780813d7018067f2796f023b56b51385970be460
Gitweb:        https://git.kernel.org/tip/780813d7018067f2796f023b56b51385970be460
Author:        Arnd Bergmann <arnd@...db.de>
AuthorDate:    Thu, 07 Aug 2025 22:53:28 +02:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Sun, 09 Nov 2025 21:01:08 +01:00

x86/math-emu: Fix div_Xsig() prototype

The third argument of div_Xsig() is the output of the division, but is marked
'const', which means the compiler is not expecting it to be updated and may
generate bad code around the call. clang-21 now warns about the pattern since
an uninitialized variable is passed into two 'const' arguments by reference:

  arch/x86/math-emu/poly_atan.c:93:28: error: variable 'argSignif' is uninitialized \
  when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
     93 |         div_Xsig(&Numer, &Denom, &argSignif);
        |                                   ^~~~~~~~~
  arch/x86/math-emu/poly_l2.c:195:29: error: variable 'argSignif' is uninitialized \
  when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
    195 |                 div_Xsig(&Numer, &Denom, &argSignif);
        |                                           ^~~~~~~~~

The implementation is in assembly, so the problem has gone unnoticed since the
code was added in the linux-1.1 days. Remove the 'const' marker here.

Fixes: e19a1bdb835c ("Import 1.1.38")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://patch.msgid.link/20250807205334.123231-1-arnd@kernel.org
---
 arch/x86/math-emu/poly.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/math-emu/poly.h b/arch/x86/math-emu/poly.h
index fc1c887..654bfe4 100644
--- a/arch/x86/math-emu/poly.h
+++ b/arch/x86/math-emu/poly.h
@@ -39,7 +39,7 @@ asmlinkage void mul_Xsig_Xsig(Xsig *dest, const Xsig *mult);
 asmlinkage void shr_Xsig(Xsig *, const int n);
 asmlinkage int round_Xsig(Xsig *);
 asmlinkage int norm_Xsig(Xsig *);
-asmlinkage void div_Xsig(Xsig *x1, const Xsig *x2, const Xsig *dest);
+asmlinkage void div_Xsig(Xsig *x1, const Xsig *x2, Xsig *dest);
 
 /* Macro to extract the most significant 32 bits from a long long */
 #define LL_MSW(x)     (((unsigned long *)&x)[1])