git: a592812327de - main - mlx5_core: fix deadlock when using RXTLS

[Martin Matuska]

The branch main has been updated by mm:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=a592812327deaf69ab226afc5c8a01af43dc03c2

commit a592812327deaf69ab226afc5c8a01af43dc03c2
Author:     Martin Matuska <m...@freebsd.org>
AuthorDate: 2023-11-13 13:29:27 +0000
Commit:     Martin Matuska <m...@freebsd.org>
CommitDate: 2023-11-16 11:17:41 +0000

    mlx5_core: fix deadlock when using RXTLS
    
    If removing a node of type FS_TYPE_FLOW_DEST we lock the flow group too
    late. This can lead to a deadlock with fs_add_dst_fg().
    
    PR:             274715
    MFC after:      1 week
    Reviewed by:    kib
    Tested by:      mm
    Differential Revision: https://reviews.freebsd.org/D42368
---
 sys/dev/mlx5/mlx5_core/mlx5_fs_tree.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/sys/dev/mlx5/mlx5_core/mlx5_fs_tree.c 
b/sys/dev/mlx5/mlx5_core/mlx5_fs_tree.c
index 5966a73c58d1..b76ea7b60582 100644
--- a/sys/dev/mlx5/mlx5_core/mlx5_fs_tree.c
+++ b/sys/dev/mlx5/mlx5_core/mlx5_fs_tree.c
@@ -229,14 +229,19 @@ static void __fs_remove_node(struct kref *kref)
 {
        struct fs_base *node = container_of(kref, struct fs_base, refcount);
 
-       if (node->parent)
+       if (node->parent) {
+               if (node->type == FS_TYPE_FLOW_DEST)
+                       mutex_lock(&node->parent->parent->lock);
                mutex_lock(&node->parent->lock);
+       }
        mutex_lock(&node->lock);
        cmd_remove_node(node);
        mutex_unlock(&node->lock);
        complete(&node->complete);
        if (node->parent) {
                mutex_unlock(&node->parent->lock);
+               if (node->type == FS_TYPE_FLOW_DEST)
+                       mutex_unlock(&node->parent->parent->lock);
                _fs_put(node->parent, _fs_remove_node, false);
        }
 }
@@ -1719,7 +1724,7 @@ static void fs_del_dst(struct mlx5_flow_rule *dst)
 
        fs_get_parent(fte, dst);
        fs_get_parent(fg, fte);
-       mutex_lock(&fg->base.lock);
+       sx_assert(&fg->base.lock.sx, SX_XLOCKED);
        memcpy(match_value, fte->val, sizeof(fte->val));
        /* ft can't be changed as fg is locked */
        fs_get_parent(ft, fg);
@@ -1739,7 +1744,6 @@ static void fs_del_dst(struct mlx5_flow_rule *dst)
        }
        call_to_del_rule_notifiers(dst, fte);
 err:
-       mutex_unlock(&fg->base.lock);
        kvfree(match_value);
 }