This is a note to let you know that I've just added the patch titled
fs: dlm: fix mismatch of plock results from userspace
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-dlm-fix-mismatch-of-plock-results-from-userspace.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 57e2c2f2d94cfd551af91cedfa1af6d972487197 Mon Sep 17 00:00:00 2001
From: Alexander Aring <aahringo@xxxxxxxxxx>
Date: Wed, 24 May 2023 12:02:04 -0400
Subject: fs: dlm: fix mismatch of plock results from userspace
From: Alexander Aring <aahringo@xxxxxxxxxx>
commit 57e2c2f2d94cfd551af91cedfa1af6d972487197 upstream.
When a waiting plock request (F_SETLKW) is sent to userspace
for processing (dlm_controld), the result is returned at a
later time. That result could be incorrectly matched to a
different waiting request in cases where the owner field is
the same (e.g. different threads in a process.) This is fixed
by comparing all the properties in the request and reply.
The results for non-waiting plock requests are now matched
based on list order because the results are returned in the
same order they were sent.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
Signed-off-by: David Teigland <teigland@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/dlm/plock.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 45 insertions(+), 13 deletions(-)
--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -395,7 +395,7 @@ static ssize_t dev_read(struct file *fil
if (op->info.flags & DLM_PLOCK_FL_CLOSE)
list_del(&op->list);
else
- list_move(&op->list, &recv_list);
+ list_move_tail(&op->list, &recv_list);
memcpy(&info, &op->info, sizeof(info));
}
spin_unlock(&ops_lock);
@@ -433,20 +433,52 @@ static ssize_t dev_write(struct file *fi
if (check_version(&info))
return -EINVAL;
+ /*
+ * The results for waiting ops (SETLKW) can be returned in any
+ * order, so match all fields to find the op. The results for
+ * non-waiting ops are returned in the order that they were sent
+ * to userspace, so match the result with the first non-waiting op.
+ */
spin_lock(&ops_lock);
- list_for_each_entry(iter, &recv_list, list) {
- if (iter->info.fsid == info.fsid &&
- iter->info.number == info.number &&
- iter->info.owner == info.owner) {
- list_del_init(&iter->list);
- memcpy(&iter->info, &info, sizeof(info));
- if (iter->data)
- do_callback = 1;
- else
- iter->done = 1;
- op = iter;
- break;
+ if (info.wait) {
+ list_for_each_entry(iter, &recv_list, list) {
+ if (iter->info.fsid == info.fsid &&
+ iter->info.number == info.number &&
+ iter->info.owner == info.owner &&
+ iter->info.pid == info.pid &&
+ iter->info.start == info.start &&
+ iter->info.end == info.end &&
+ iter->info.ex == info.ex &&
+ iter->info.wait) {
+ op = iter;
+ break;
+ }
}
+ } else {
+ list_for_each_entry(iter, &recv_list, list) {
+ if (!iter->info.wait) {
+ op = iter;
+ break;
+ }
+ }
+ }
+
+ if (op) {
+ /* Sanity check that op and info match. */
+ if (info.wait)
+ WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK);
+ else
+ WARN_ON(op->info.fsid != info.fsid ||
+ op->info.number != info.number ||
+ op->info.owner != info.owner ||
+ op->info.optype != info.optype);
+
+ list_del_init(&op->list);
+ memcpy(&op->info, &info, sizeof(info));
+ if (op->data)
+ do_callback = 1;
+ else
+ op->done = 1;
}
spin_unlock(&ops_lock);
Patches currently in stable-queue which might be from aahringo@xxxxxxxxxx are
queue-6.4/fs-dlm-return-positive-pid-value-for-f_getlk.patch
queue-6.4/fs-dlm-fix-cleanup-pending-ops-when-interrupted.patch
queue-6.4/fs-dlm-make-f_setlk-use-unkillable-wait_event.patch
queue-6.4/fs-dlm-revert-check-required-context-while-close.patch
queue-6.4/fs-dlm-fix-missing-pending-to-false.patch
queue-6.4/fs-dlm-fix-mismatch-of-plock-results-from-userspace.patch
queue-6.4/fs-dlm-clear-pending-bit-when-queue-was-empty.patch
queue-6.4/fs-dlm-interrupt-posix-locks-only-when-process-is-killed.patch
