[PATCH OLK-6.6 0/2] CVE-2025-39697
Christoph Hellwig (1): nfs: fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests Trond Myklebust (1): NFS: Fix a race when updating an existing write fs/nfs/pagelist.c | 86 ++--------------------- fs/nfs/write.c | 146 +++++++++++++++++++++++++-------------- include/linux/nfs_page.h | 2 +- 3 files changed, 100 insertions(+), 134 deletions(-) -- 2.46.1
From: Christoph Hellwig <hch@lst.de> stable inclusion from stable-v6.6.104 commit 9a1963404cc2eef69d2f8a42861bdf63d087dd5d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICWO2H CVE: CVE-2025-39697 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 25edbcac6e32eab345e470d56ca9974a577b878b upstream. Fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests to prepare for future changes to this code, and move the helpers to write.c as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- fs/nfs/pagelist.c | 77 ---------------------------------------- fs/nfs/write.c | 75 ++++++++++++++++++++++++++++++++++---- include/linux/nfs_page.h | 1 - 3 files changed, 69 insertions(+), 84 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 040b6b79c75e..30e2488eb84c 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -206,83 +206,6 @@ nfs_page_group_lock_head(struct nfs_page *req) return head; } -/* - * nfs_unroll_locks - unlock all newly locked reqs and wait on @req - * @head: head request of page group, must be holding head lock - * @req: request that couldn't lock and needs to wait on the req bit lock - * - * This is a helper function for nfs_lock_and_join_requests - * returns 0 on success, < 0 on error. - */ -static void -nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req) -{ - struct nfs_page *tmp; - - /* relinquish all the locks successfully grabbed this run */ - for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) { - if (!kref_read(&tmp->wb_kref)) - continue; - nfs_unlock_and_release_request(tmp); - } -} - -/* - * nfs_page_group_lock_subreq - try to lock a subrequest - * @head: head request of page group - * @subreq: request to lock - * - * This is a helper function for nfs_lock_and_join_requests which - * must be called with the head request and page group both locked. - * On error, it returns with the page group unlocked. - */ -static int -nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq) -{ - int ret; - - if (!kref_get_unless_zero(&subreq->wb_kref)) - return 0; - while (!nfs_lock_request(subreq)) { - nfs_page_group_unlock(head); - ret = nfs_wait_on_request(subreq); - if (!ret) - ret = nfs_page_group_lock(head); - if (ret < 0) { - nfs_unroll_locks(head, subreq); - nfs_release_request(subreq); - return ret; - } - } - return 0; -} - -/* - * nfs_page_group_lock_subrequests - try to lock the subrequests - * @head: head request of page group - * - * This is a helper function for nfs_lock_and_join_requests which - * must be called with the head request locked. - */ -int nfs_page_group_lock_subrequests(struct nfs_page *head) -{ - struct nfs_page *subreq; - int ret; - - ret = nfs_page_group_lock(head); - if (ret < 0) - return ret; - /* lock each request in the page group */ - for (subreq = head->wb_this_page; subreq != head; - subreq = subreq->wb_this_page) { - ret = nfs_page_group_lock_subreq(head, subreq); - if (ret < 0) - return ret; - } - nfs_page_group_unlock(head); - return 0; -} - /* * nfs_page_set_headlock - set the request PG_HEADLOCK * @req: request that is to be locked diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 6bc36cef14cd..866a6931e97b 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -548,6 +548,57 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo, nfs_destroy_unlinked_subrequests(destroy_list, head, inode); } +/* + * nfs_unroll_locks - unlock all newly locked reqs and wait on @req + * @head: head request of page group, must be holding head lock + * @req: request that couldn't lock and needs to wait on the req bit lock + * + * This is a helper function for nfs_lock_and_join_requests + * returns 0 on success, < 0 on error. + */ +static void +nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req) +{ + struct nfs_page *tmp; + + /* relinquish all the locks successfully grabbed this run */ + for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) { + if (!kref_read(&tmp->wb_kref)) + continue; + nfs_unlock_and_release_request(tmp); + } +} + +/* + * nfs_page_group_lock_subreq - try to lock a subrequest + * @head: head request of page group + * @subreq: request to lock + * + * This is a helper function for nfs_lock_and_join_requests which + * must be called with the head request and page group both locked. + * On error, it returns with the page group unlocked. + */ +static int +nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq) +{ + int ret; + + if (!kref_get_unless_zero(&subreq->wb_kref)) + return 0; + while (!nfs_lock_request(subreq)) { + nfs_page_group_unlock(head); + ret = nfs_wait_on_request(subreq); + if (!ret) + ret = nfs_page_group_lock(head); + if (ret < 0) { + nfs_unroll_locks(head, subreq); + nfs_release_request(subreq); + return ret; + } + } + return 0; +} + /* * nfs_lock_and_join_requests - join all subreqs to the head req * @folio: the folio used to lookup the "page group" of nfs_page structures @@ -566,7 +617,7 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo, static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio) { struct inode *inode = folio_file_mapping(folio)->host; - struct nfs_page *head; + struct nfs_page *head, *subreq; struct nfs_commit_info cinfo; int ret; @@ -580,16 +631,28 @@ static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio) if (IS_ERR_OR_NULL(head)) return head; + ret = nfs_page_group_lock(head); + if (ret < 0) + goto out_unlock; + /* lock each request in the page group */ - ret = nfs_page_group_lock_subrequests(head); - if (ret < 0) { - nfs_unlock_and_release_request(head); - return ERR_PTR(ret); + for (subreq = head->wb_this_page; + subreq != head; + subreq = subreq->wb_this_page) { + ret = nfs_page_group_lock_subreq(head, subreq); + if (ret < 0) + goto out_unlock; } - nfs_join_page_group(head, &cinfo, inode); + nfs_page_group_unlock(head); + nfs_init_cinfo_from_inode(&cinfo, inode); + nfs_join_page_group(head, &cinfo, inode); return head; + +out_unlock: + nfs_unlock_and_release_request(head); + return ERR_PTR(ret); } static void nfs_write_error(struct nfs_page *req, int error) diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 1c315f854ea8..3a0f7ebe5388 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -156,7 +156,6 @@ extern int nfs_wait_on_request(struct nfs_page *); extern void nfs_unlock_request(struct nfs_page *req); extern void nfs_unlock_and_release_request(struct nfs_page *); extern struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req); -extern int nfs_page_group_lock_subrequests(struct nfs_page *head); extern void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo, struct inode *inode); -- 2.46.1
From: Trond Myklebust <trond.myklebust@hammerspace.com> stable inclusion from stable-v6.6.104 commit 181feb41f0b268e6288bf9a7b984624d7fe2031d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICWO2H CVE: CVE-2025-39697 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 76d2e3890fb169168c73f2e4f8375c7cc24a765e upstream. After nfs_lock_and_join_requests() tests for whether the request is still attached to the mapping, nothing prevents a call to nfs_inode_remove_request() from succeeding until we actually lock the page group. The reason is that whoever called nfs_inode_remove_request() doesn't necessarily have a lock on the page group head. So in order to avoid races, let's take the page group lock earlier in nfs_lock_and_join_requests(), and hold it across the removal of the request in nfs_inode_remove_request(). Reported-by: Jeff Layton <jlayton@kernel.org> Tested-by: Joe Quanaim <jdq@meta.com> Tested-by: Andrew Steffen <aksteffen@meta.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Fixes: bd37d6fce184 ("NFSv4: Convert nfs_lock_and_join_requests() to use nfs_page_find_head_request()") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- fs/nfs/pagelist.c | 9 ++--- fs/nfs/write.c | 71 ++++++++++++++-------------------------- include/linux/nfs_page.h | 1 + 3 files changed, 31 insertions(+), 50 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 30e2488eb84c..0ea3916ed1dc 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -272,13 +272,14 @@ nfs_page_group_unlock(struct nfs_page *req) nfs_page_clear_headlock(req); } -/* - * nfs_page_group_sync_on_bit_locked +/** + * nfs_page_group_sync_on_bit_locked - Test if all requests have @bit set + * @req: request in page group + * @bit: PG_* bit that is used to sync page group * * must be called with page group lock held */ -static bool -nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit) +bool nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit) { struct nfs_page *head = req->wb_head; struct nfs_page *tmp; diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 866a6931e97b..edd6a8ba71b7 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -156,20 +156,10 @@ nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode) } } -static int -nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode) +static void nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode) { - int ret; - - if (!test_bit(PG_REMOVE, &req->wb_flags)) - return 0; - ret = nfs_page_group_lock(req); - if (ret) - return ret; if (test_and_clear_bit(PG_REMOVE, &req->wb_flags)) nfs_page_set_inode_ref(req, inode); - nfs_page_group_unlock(req); - return 0; } static struct nfs_page *nfs_folio_private_request(struct folio *folio) @@ -238,36 +228,6 @@ static struct nfs_page *nfs_folio_find_head_request(struct folio *folio) return req; } -static struct nfs_page *nfs_folio_find_and_lock_request(struct folio *folio) -{ - struct inode *inode = folio_file_mapping(folio)->host; - struct nfs_page *req, *head; - int ret; - - for (;;) { - req = nfs_folio_find_head_request(folio); - if (!req) - return req; - head = nfs_page_group_lock_head(req); - if (head != req) - nfs_release_request(req); - if (IS_ERR(head)) - return head; - ret = nfs_cancel_remove_inode(head, inode); - if (ret < 0) { - nfs_unlock_and_release_request(head); - return ERR_PTR(ret); - } - /* Ensure that nobody removed the request before we locked it */ - if (head == nfs_folio_private_request(folio)) - break; - if (folio_test_swapcache(folio)) - break; - nfs_unlock_and_release_request(head); - } - return head; -} - /* Adjust the file length if we're writing beyond the end */ static void nfs_grow_file(struct folio *folio, unsigned int offset, unsigned int count) @@ -621,20 +581,37 @@ static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio) struct nfs_commit_info cinfo; int ret; - nfs_init_cinfo_from_inode(&cinfo, inode); /* * A reference is taken only on the head request which acts as a * reference to the whole page group - the group will not be destroyed * until the head reference is released. */ - head = nfs_folio_find_and_lock_request(folio); - if (IS_ERR_OR_NULL(head)) - return head; +retry: + head = nfs_folio_find_head_request(folio); + if (!head) + return NULL; + + while (!nfs_lock_request(head)) { + ret = nfs_wait_on_request(head); + if (ret < 0) { + nfs_release_request(head); + return ERR_PTR(ret); + } + } ret = nfs_page_group_lock(head); if (ret < 0) goto out_unlock; + /* Ensure that nobody removed the request before we locked it */ + if (head != folio->private && !folio_test_swapcache(folio)) { + nfs_page_group_unlock(head); + nfs_unlock_and_release_request(head); + goto retry; + } + + nfs_cancel_remove_inode(head, inode); + /* lock each request in the page group */ for (subreq = head->wb_this_page; subreq != head; @@ -855,7 +832,8 @@ static void nfs_inode_remove_request(struct nfs_page *req) { struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req)); - if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) { + nfs_page_group_lock(req); + if (nfs_page_group_sync_on_bit_locked(req, PG_REMOVE)) { struct folio *folio = nfs_page_to_folio(req->wb_head); struct address_space *mapping = folio_file_mapping(folio); @@ -867,6 +845,7 @@ static void nfs_inode_remove_request(struct nfs_page *req) } spin_unlock(&mapping->private_lock); } + nfs_page_group_unlock(req); if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) { atomic_long_dec(&nfsi->nrequests); diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 3a0f7ebe5388..6a46069c5a36 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -162,6 +162,7 @@ extern void nfs_join_page_group(struct nfs_page *head, extern int nfs_page_group_lock(struct nfs_page *); extern void nfs_page_group_unlock(struct nfs_page *); extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int); +extern bool nfs_page_group_sync_on_bit_locked(struct nfs_page *, unsigned int); extern int nfs_page_set_headlock(struct nfs_page *req); extern void nfs_page_clear_headlock(struct nfs_page *req); extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *); -- 2.46.1
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