From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA65A3C553A; Mon, 20 Apr 2026 13:17:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776691054; cv=none; b=OC/sWbG2EIgLgu1MpkCNpXXjqDWHuMU1mYBdrPozZQRzJKidn/1BsWnVlsMHjPMA8fj7bXnzPPC8uYRlDIG5xv80/uiD154r7PIYjQeR+jjWhlza9sN+OoBe6pr5Ff0R62ZQKZXjBrbxhWX9rs0VoxDlDAwhWYAL52eGkkWIgEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776691054; c=relaxed/simple; bh=2SxazbbS9oAi21Q7GCbtTy4MJm0ReOyr2NXSzDd7QZw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Tb5fKQfLe5BIWR2blr/bnKtIiWEvSIvMr9KsXCPjseZ2XruTydIztUAFYW4qLx92PSjGdOKfWTdZaFOenjViD2Z6Ffj0YZr3SelOlYXqXQgIqNIV7VQ7NPlj2paR7TJo2zamyvJOB4AHgUK6kC2el/bEfQipfazwZOH5Av3Omv8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xwydb+Mj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Xwydb+Mj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18BD5C2BCB6; Mon, 20 Apr 2026 13:17:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776691054; bh=2SxazbbS9oAi21Q7GCbtTy4MJm0ReOyr2NXSzDd7QZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xwydb+MjE38Yz9wYsZXCGWZYWrHWsEcBXCdCsRZtkpXb41BtpGs6AlBxVvjQ3smkI xw/QvsEQTRuPfzI7DWy/zEmrmCEg1VqEjcuz4KzbAIQH/VhHdNE7sqIeqo4Ir9DYYJ bn+j345Wqv90UavNBj0FWgAE4Dq2oECYsudZJYrqQ5QLyrWL5gJB2zDrQGmCgopI8g kCxReA9D8SGG4ijUdlo6jhYihcoTGJ5cL8ZyVeElzlZcLVBStVXT/C1+zgLWZM9Mi8 wXQ2fRkJqCggDws+bDDgfGcj+9rUDrTBui+tLfsxaNOlWYGfMBjLLi/8fVYIQ8oWbT vbQIBf8tXZCQA== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Linus Torvalds , =?UTF-8?q?=EA=B9=80=EC=98=81=EB=AF=BC?= , Oleg Nesterov , Dave Hansen , Rick Edgecombe , Sasha Levin , tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, surenb@google.com, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 6.18] x86: shadow stacks: proper error handling for mmap lock Date: Mon, 20 Apr 2026 09:08:53 -0400 Message-ID: <20260420131539.986432-67-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420131539.986432-1-sashal@kernel.org> References: <20260420131539.986432-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.23 Content-Transfer-Encoding: 8bit From: Linus Torvalds [ Upstream commit 52f657e34d7b21b47434d9d8b26fa7f6778b63a0 ] 김영민 reports that shstk_pop_sigframe() doesn't check for errors from mmap_read_lock_killable(), which is a silly oversight, and also shows that we haven't marked those functions with "__must_check", which would have immediately caught it. So let's fix both issues. Reported-by: 김영민 Acked-by: Oleg Nesterov Acked-by: Dave Hansen Acked-by: Rick Edgecombe Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Error: Failed to generate final synthesis arch/x86/kernel/shstk.c | 3 ++- include/linux/mmap_lock.h | 6 +++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 978232b6d48d7..ff8edea8511b4 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -351,7 +351,8 @@ static int shstk_pop_sigframe(unsigned long *ssp) need_to_check_vma = PAGE_ALIGN(*ssp) == *ssp; if (need_to_check_vma) - mmap_read_lock_killable(current->mm); + if (mmap_read_lock_killable(current->mm)) + return -EINTR; err = get_shstk_data(&token_addr, (unsigned long __user *)*ssp); if (unlikely(err)) diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 2c9fffa58714f..95ee1f224c492 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -322,7 +322,7 @@ static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass) __mmap_lock_trace_acquire_returned(mm, true, true); } -static inline int mmap_write_lock_killable(struct mm_struct *mm) +static inline int __must_check mmap_write_lock_killable(struct mm_struct *mm) { int ret; @@ -369,7 +369,7 @@ static inline void mmap_read_lock(struct mm_struct *mm) __mmap_lock_trace_acquire_returned(mm, false, true); } -static inline int mmap_read_lock_killable(struct mm_struct *mm) +static inline int __must_check mmap_read_lock_killable(struct mm_struct *mm) { int ret; @@ -379,7 +379,7 @@ static inline int mmap_read_lock_killable(struct mm_struct *mm) return ret; } -static inline bool mmap_read_trylock(struct mm_struct *mm) +static inline bool __must_check mmap_read_trylock(struct mm_struct *mm) { bool ret; -- 2.53.0