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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Chris Mason , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3516; i=david@kernel.org; h=from:subject:message-id; bh=llGJ6NdJiWik0yJaZwx3srvBERv6b9fGHgw5NUViur8=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer21Ju85syDihqpSx8kZevq/BZ7vdCS+E9j8/nxLpZ /XE2Ia3o5SFQYyDQVZMkSUo+L7By5fraqvd+Jhh5rAygQxh4OIUgImo6DP8j8p2PfZIeerUF4kK Hjnn3G2C5wiVWez72jNt+fOvrBv2ejH84b6byOPtzq2/yLfz8kkfNWWZyr3pRUYsIhJrNjtK6AX xAQA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 7F46F180003 X-Rspam-User: X-Stat-Signature: biupy8g41us7d41s3jf8sttewa9rsbor X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793306054-780677 X-HE-Meta: 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 ZclQi2XK c15qWU4dv0vGD0W6hD5rdrEyMKpMrZ/UrxotbH74HNw6yFFHaJxwq4DwVKTNTuKGgqUMYeXxW4nyqZF0isoduyYAYiW+3Q5k/M3R001tEiWeTuxYNpwrqBltArP4+gxhcejoEFIVusHI5tpKI0KovM7PgBhveISwW7gzYYbLENw/QEIy0DiqXHjO53Dz3WwPzV1xtmfGcDefjd6Bq/4q6sVTg54xY3NpTxvKQJcpNBAQd6KmUy4Wpf+aKBJocT+BD+HFMNFZHIp71pt/fJK1bDaavEtNsehAr30oCn5amrHNMpGdhAUIH94zsZR7caPDi16lksI2CXj2rh3pZ4OenZ9SM0rP7ay/nIS38i19tpqLSRwiKTiu/XUMlbD7WVWde047m Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 shmem_file() only checks a file's backing mapping. That mapping can belong to another file, as with a Coda file backed by a tmpfs container after mmap(). It does not establish that file_inode(file) is a shmem inode. Seal handling and memfd preservation use this check before accessing shmem inode state, so they can access an inode of the wrong type. Add file_inode_is_shmem() to check the inode's file operations in both paths. This identifies regular shmem inodes, including those used by memfds and ordinary tmpfs files, independently of wrapper file operations. Fixes: c49fcfcda8b5 ("mm/shmem: update file sealing comments and file checking") Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd") Cc: stable@vger.kernel.org Reported-by: Chris Mason Reviewed-by: Rik van Riel Reviewed-by: Mike Rapoport (Microsoft) Signed-off-by: David Hildenbrand (Arm) --- include/linux/shmem_fs.h | 6 ++++++ mm/memfd.c | 8 +++++--- mm/memfd_luo.c | 2 +- mm/shmem.c | 5 +++++ 4 files changed, 17 insertions(+), 4 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index a7c7a96a7cbf..4996420cfe60 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -117,8 +117,14 @@ extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); #ifdef CONFIG_SHMEM +bool inode_is_shmem(const struct inode *inode); bool shmem_mapping(const struct address_space *mapping); #else +static inline bool inode_is_shmem(const struct inode *inode) +{ + return false; +} + static inline bool shmem_mapping(const struct address_space *mapping) { return false; diff --git a/mm/memfd.c b/mm/memfd.c index 0f6fff004f5e..507c00ce0fda 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -211,12 +211,14 @@ static int memfd_wait_for_pins(struct address_space *mapping) static unsigned int *memfd_file_seals_ptr(struct file *file) { - if (shmem_file(file)) - return &SHMEM_I(file_inode(file))->seals; + struct inode *inode = file_inode(file); + + if (inode_is_shmem(inode)) + return &SHMEM_I(inode)->seals; #ifdef CONFIG_HUGETLBFS if (is_file_hugepages(file)) - return &HUGETLBFS_I(file_inode(file))->seals; + return &HUGETLBFS_I(inode)->seals; #endif return NULL; diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index 6b68220275eb..adaab98c8b63 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -581,7 +581,7 @@ static bool memfd_luo_can_preserve(struct liveupdate_file_handler *handler, { struct inode *inode = file_inode(file); - return shmem_file(file) && !inode->i_nlink; + return inode_is_shmem(inode) && !inode->i_nlink; } static unsigned long memfd_luo_get_id(struct file *file) diff --git a/mm/shmem.c b/mm/shmem.c index af21a89abb0f..0ca5b7f7a517 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -275,6 +275,11 @@ static const struct vm_operations_struct shmem_vm_ops; static const struct vm_operations_struct shmem_anon_vm_ops; static struct file_system_type shmem_fs_type; +bool inode_is_shmem(const struct inode *inode) +{ + return inode->i_fop == &shmem_file_operations; +} + bool shmem_mapping(const struct address_space *mapping) { return mapping->a_ops == &shmem_aops; -- 2.43.0