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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> 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 X-Stat-Signature: n51cra3wkitszdbgjryimi6szp8nb9y8 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E2326C0007 X-Rspam-User: X-HE-Tag: 1776691055-536692 X-HE-Meta: U2FsdGVkX1/rBL5eFkYmx6SK2UnM4o3DP262SA04S+7JqV5+nehnIxxl0Jb69NWJQoTz2bVMwDbpHWAyqZAd9251LF73VTGRhNw4Yi1OXU79EIgNbQTyPQ2e4nc4z0Dn/UWEUoxqRNijK3vTOy35ZsVVN90pnWWEIn12Pcp0jsR5YsqPPJKyRtnPube+J8IiUVTJhwPK2rwoV4dROvHV+k3JRD3ZgerSBVhVIqNGJinl5OVuvs73OgEEJxzQQ6nhRBRBwl+s8V9LOY+pyAS84dy82rAjRSbanPxP+ZuFDaN4j6atYNz6uuNysJ2pj3rkURMrZ+xbxP8PJMaCdpML0o+9vsFinVczsQSw6dVZKZ56lUSt2ACQNC/wjpbFRu7JJFGxVlSclUWHwKKnVoERFY1fxn8EUxdqxx58Yw46yyRwzt778rRFHQfsoYzmr8FDCzilSYrIKC/C3nQ0ITH6wsqWhKxfIXj1Cv4gR8kARWtyLj1vTwfQeQLjUX6oZVerdz0PIqp/hUb0wo+gaRi0PwKUhg26witrJr/4dzQV7pZm6koOXJrZ/jNP7bhRI3CtMZIUfg9FIpFnoYUZ0LQka1aHdXv94w93f+HLX5uaGXOBhGfGvqx3Eqth0Eqn8nvBBGpy8oo4FBrLSUoSO6RYREnbU4eDcfy/pDDr/iRwVhwZVfKdQlQkk3TFsP+CCJ4PDAOKdn4URUJM94jUHftAlrDS+JHm/FUfnWs/8wUAnZhlYEW2NGHRsRtGhzEVv7/fjRQ+ISLTownFqqiDjt/iX5/cRJBTP8s3rsoAWtBoKeVkdDMXfKqZf8tfkxYg0fp9b8SRaBLGLhuoGVXJIOW1N95VGLViQxTinBKMk2Ob/ngC77zUXfrO2FhvINX0N5ZSypLi3uxvcU2a1v/aHG5RDs1UXLP20CNhJiO/NaAVmONqSWZBdZLU0SdSMFr34bBqM5+CGXbBGldZqSVDIJ0 vMd1o8eq lZaGaO85gAit4QkSs8qnRtlxGPZKGiKttpW5L3YmRpx/++zPuRlD+QVNSoF9XlwGZMdHLVRrJua18tWuHG94gsMX7lHSjCeFnmdUEDkFz8g54hLFnr79B+JpWQMl80YBZHEcRxDkwICWcaLwwVUj4fpDu+UgYPVxpVwYlSIa6NBWhJ1WIsnm5gtkJazyZTIweyQyqbN4rcEjGEvKhe9f+v1nPvBhROvmPehrJiV07j2B588eFy50WlFW7p5XmgYGNlbJ/Q/NCNzDm/2C+9yZkmduYwiisBWp34hmHHhw9KqaXaQLL7IPig8he3fooPwG6nvUExoFmJ2V8oFBiyISqNNkTW6V/t8lrWCEkvSSgHtjWpyYQ60mKRrUUIBfDYQFSFvr/ERz7xYG/iRGKHgLevk71Eg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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