HWPoison: my reading of folio_test_hwpoison() is that it only tests the
head page of a large folio, whereas splice_folio_into_pipe() will splice
as much of the folio as it can: so for safety we should also check the
has_hwpoisoned flag, set if any of the folio's pages are hwpoisoned.
(Perhaps that ugliness can be improved at the mm end later.)
The call to splice_zeropage_into_pipe() risked overrunning past EOF:
ask it for "part" not "len".
Fixes: bd194b187115 ("shmem: Implement splice-read")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: David Howells <dhowells@xxxxxxxxxx>
---
This went into Jens's tree for a while, but got lost when another version
of the splice series arrived. The reviewed version did contain two more
mods: but its !len check is now done at the upper level, and its *ppos
check is unnecessary, given the *ppos check at the start of the loop.
mm/shmem.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 2f2e0e618072..f5af4b943e42 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2796,7 +2796,8 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
if (*ppos >= i_size_read(inode))
break;
- error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio, SGP_READ);
+ error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio,
+ SGP_READ);
if (error) {
if (error == -EINVAL)
error = 0;
@@ -2805,7 +2806,9 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
if (folio) {
folio_unlock(folio);
- if (folio_test_hwpoison(folio)) {
+ if (folio_test_hwpoison(folio) ||
+ (folio_test_large(folio) &&
+ folio_test_has_hwpoisoned(folio))) {
error = -EIO;
break;
}
@@ -2841,7 +2844,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
folio_put(folio);
folio = NULL;
} else {
- n = splice_zeropage_into_pipe(pipe, *ppos, len);
+ n = splice_zeropage_into_pipe(pipe, *ppos, part);
}
if (!n)
--
2.35.3
