The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 76d2e3890fb169168c73f2e4f8375c7cc24a765e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082225-cling-drainer-d884@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 76d2e3890fb169168c73f2e4f8375c7cc24a765e Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust(a)hammerspace.com>
Date: Sat, 16 Aug 2025 07:25:20 -0700
Subject: [PATCH] NFS: Fix a race when updating an existing write
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(a)kernel.org>
Tested-by: Joe Quanaim <jdq(a)meta.com>
Tested-by: Andrew Steffen <aksteffen(a)meta.com>
Reviewed-by: Jeff Layton <jlayton(a)kernel.org>
Fixes: bd37d6fce184 ("NFSv4: Convert nfs_lock_and_join_requests() to use nfs_page_find_head_request()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust(a)hammerspace.com>
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 11968dcb7243..6e69ce43a13f 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -253,13 +253,14 @@ 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 fa5c41d0989a..8b7c04737967 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -153,20 +153,10 @@ 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;
}
/**
@@ -585,19 +575,18 @@ retry:
}
}
+ 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) {
+ nfs_page_group_unlock(head);
nfs_unlock_and_release_request(head);
goto retry;
}
- ret = nfs_cancel_remove_inode(head, inode);
- if (ret < 0)
- goto out_unlock;
-
- ret = nfs_page_group_lock(head);
- if (ret < 0)
- goto out_unlock;
+ nfs_cancel_remove_inode(head, inode);
/* lock each request in the page group */
for (subreq = head->wb_this_page;
@@ -786,7 +775,8 @@ 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->mapping;
@@ -798,6 +788,7 @@ static void nfs_inode_remove_request(struct nfs_page *req)
}
spin_unlock(&mapping->i_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 169b4ae30ff4..9aed39abc94b 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -160,6 +160,7 @@ 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 *);
If an object is backed up to shmem it is incorrectly identified
as not having valid data by the move code. This means moving
to VRAM skips the -EMULTIHOP step and the bo is cleared. This
causes all sorts of weird behaviour on DGFX if an already evicted
object is targeted by the shrinker.
Fix this by using ttm_tt_is_swapped() to identify backed-up
objects.
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/5996
Fixes: 00c8efc3180f ("drm/xe: Add a shrinker for xe bos")
Cc: Matthew Brost <matthew.brost(a)intel.com>
Cc: Matthew Auld <matthew.auld(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v6.15+
Signed-off-by: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
---
drivers/gpu/drm/xe/xe_bo.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 7d1ff642b02a..4faf15d5fa6d 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -823,8 +823,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
return ret;
}
- tt_has_data = ttm && (ttm_tt_is_populated(ttm) ||
- (ttm->page_flags & TTM_TT_FLAG_SWAPPED));
+ tt_has_data = ttm && (ttm_tt_is_populated(ttm) || ttm_tt_is_swapped(ttm));
move_lacks_source = !old_mem || (handle_system_ccs ? (!bo->ccs_cleared) :
(!mem_type_is_vram(old_mem_type) && !tt_has_data));
--
2.50.1
Commit 3215eaceca87 ("mm/mremap: refactor initial parameter sanity
checks") moved the sanity check for vrm->new_addr from mremap_to() to
check_mremap_params().
However, this caused a regression as vrm->new_addr is now checked even
when MREMAP_FIXED and MREMAP_DONTUNMAP flags are not specified. In this
case, vrm->new_addr can be garbage and create unexpected failures.
Fix this by moving the new_addr check after the vrm_implies_new_addr()
guard. This ensures that the new_addr is only checked when the user has
specified one explicitly.
Cc: stable(a)vger.kernel.org
Fixes: 3215eaceca87 ("mm/mremap: refactor initial parameter sanity checks")
Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com>
Signed-off-by: Carlos Llamas <cmllamas(a)google.com>
---
v2:
- split out vrm->new_len into individual checks
- cc stable, collect tags
v1:
https://lore.kernel.org/all/20250828032653.521314-1-cmllamas@google.com/
mm/mremap.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index e618a706aff5..35de0a7b910e 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1774,15 +1774,18 @@ static unsigned long check_mremap_params(struct vma_remap_struct *vrm)
if (!vrm->new_len)
return -EINVAL;
- /* Is the new length or address silly? */
- if (vrm->new_len > TASK_SIZE ||
- vrm->new_addr > TASK_SIZE - vrm->new_len)
+ /* Is the new length silly? */
+ if (vrm->new_len > TASK_SIZE)
return -EINVAL;
/* Remainder of checks are for cases with specific new_addr. */
if (!vrm_implies_new_addr(vrm))
return 0;
+ /* Is the new address silly? */
+ if (vrm->new_addr > TASK_SIZE - vrm->new_len)
+ return -EINVAL;
+
/* The new address must be page-aligned. */
if (offset_in_page(vrm->new_addr))
return -EINVAL;
--
2.51.0.268.g9569e192d0-goog