This is a note to let you know that I've just added the patch titled
net/mlx5: fs, lock FTE when checking if active
to the 5.4-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:
net-mlx5-fs-lock-fte-when-checking-if-active.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4f766965d5905da5da42cfb6121cf2a27973b6f5
Author: Mark Bloch <mbloch@xxxxxxxxxx>
Date: Thu Nov 7 20:35:23 2024 +0200
net/mlx5: fs, lock FTE when checking if active
[ Upstream commit 9ca314419930f9135727e39d77e66262d5f7bef6 ]
The referenced commits introduced a two-step process for deleting FTEs:
- Lock the FTE, delete it from hardware, set the hardware deletion function
to NULL and unlock the FTE.
- Lock the parent flow group, delete the software copy of the FTE, and
remove it from the xarray.
However, this approach encounters a race condition if a rule with the same
match value is added simultaneously. In this scenario, fs_core may set the
hardware deletion function to NULL prematurely, causing a panic during
subsequent rule deletions.
To prevent this, ensure the active flag of the FTE is checked under a lock,
which will prevent the fs_core layer from attaching a new steering rule to
an FTE that is in the process of deletion.
[ 438.967589] MOSHE: 2496 mlx5_del_flow_rules del_hw_func
[ 438.968205] ------------[ cut here ]------------
[ 438.968654] refcount_t: decrement hit 0; leaking memory.
[ 438.969249] WARNING: CPU: 0 PID: 8957 at lib/refcount.c:31 refcount_warn_saturate+0xfb/0x110
[ 438.970054] Modules linked in: act_mirred cls_flower act_gact sch_ingress openvswitch nsh mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core zram zsmalloc fuse [last unloaded: cls_flower]
[ 438.973288] CPU: 0 UID: 0 PID: 8957 Comm: tc Not tainted 6.12.0-rc1+ #8
[ 438.973888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 438.974874] RIP: 0010:refcount_warn_saturate+0xfb/0x110
[ 438.975363] Code: 40 66 3b 82 c6 05 16 e9 4d 01 01 e8 1f 7c a0 ff 0f 0b c3 cc cc cc cc 48 c7 c7 10 66 3b 82 c6 05 fd e8 4d 01 01 e8 05 7c a0 ff <0f> 0b c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90
[ 438.976947] RSP: 0018:ffff888124a53610 EFLAGS: 00010286
[ 438.977446] RAX: 0000000000000000 RBX: ffff888119d56de0 RCX: 0000000000000000
[ 438.978090] RDX: ffff88852c828700 RSI: ffff88852c81b3c0 RDI: ffff88852c81b3c0
[ 438.978721] RBP: ffff888120fa0e88 R08: 0000000000000000 R09: ffff888124a534b0
[ 438.979353] R10: 0000000000000001 R11: 0000000000000001 R12: ffff888119d56de0
[ 438.979979] R13: ffff888120fa0ec0 R14: ffff888120fa0ee8 R15: ffff888119d56de0
[ 438.980607] FS: 00007fe6dcc0f800(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000
[ 438.983984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 438.984544] CR2: 00000000004275e0 CR3: 0000000186982001 CR4: 0000000000372eb0
[ 438.985205] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 438.985842] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 438.986507] Call Trace:
[ 438.986799] <TASK>
[ 438.987070] ? __warn+0x7d/0x110
[ 438.987426] ? refcount_warn_saturate+0xfb/0x110
[ 438.987877] ? report_bug+0x17d/0x190
[ 438.988261] ? prb_read_valid+0x17/0x20
[ 438.988659] ? handle_bug+0x53/0x90
[ 438.989054] ? exc_invalid_op+0x14/0x70
[ 438.989458] ? asm_exc_invalid_op+0x16/0x20
[ 438.989883] ? refcount_warn_saturate+0xfb/0x110
[ 438.990348] mlx5_del_flow_rules+0x2f7/0x340 [mlx5_core]
[ 438.990932] __mlx5_eswitch_del_rule+0x49/0x170 [mlx5_core]
[ 438.991519] ? mlx5_lag_is_sriov+0x3c/0x50 [mlx5_core]
[ 438.992054] ? xas_load+0x9/0xb0
[ 438.992407] mlx5e_tc_rule_unoffload+0x45/0xe0 [mlx5_core]
[ 438.993037] mlx5e_tc_del_fdb_flow+0x2a6/0x2e0 [mlx5_core]
[ 438.993623] mlx5e_flow_put+0x29/0x60 [mlx5_core]
[ 438.994161] mlx5e_delete_flower+0x261/0x390 [mlx5_core]
[ 438.994728] tc_setup_cb_destroy+0xb9/0x190
[ 438.995150] fl_hw_destroy_filter+0x94/0xc0 [cls_flower]
[ 438.995650] fl_change+0x11a4/0x13c0 [cls_flower]
[ 438.996105] tc_new_tfilter+0x347/0xbc0
[ 438.996503] ? ___slab_alloc+0x70/0x8c0
[ 438.996929] rtnetlink_rcv_msg+0xf9/0x3e0
[ 438.997339] ? __netlink_sendskb+0x4c/0x70
[ 438.997751] ? netlink_unicast+0x286/0x2d0
[ 438.998171] ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[ 438.998625] netlink_rcv_skb+0x54/0x100
[ 438.999020] netlink_unicast+0x203/0x2d0
[ 438.999421] netlink_sendmsg+0x1e4/0x420
[ 438.999820] __sock_sendmsg+0xa1/0xb0
[ 439.000203] ____sys_sendmsg+0x207/0x2a0
[ 439.000600] ? copy_msghdr_from_user+0x6d/0xa0
[ 439.001072] ___sys_sendmsg+0x80/0xc0
[ 439.001459] ? ___sys_recvmsg+0x8b/0xc0
[ 439.001848] ? generic_update_time+0x4d/0x60
[ 439.002282] __sys_sendmsg+0x51/0x90
[ 439.002658] do_syscall_64+0x50/0x110
[ 439.003040] entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: 718ce4d601db ("net/mlx5: Consolidate update FTE for all removal changes")
Fixes: cefc23554fc2 ("net/mlx5: Fix FTE cleanup")
Signed-off-by: Mark Bloch <mbloch@xxxxxxxxxx>
Reviewed-by: Maor Gottlieb <maorg@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Link: https://patch.msgid.link/20241107183527.676877-4-tariqt@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 93fcde150a42f..30d5b7f52a2a0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1678,13 +1678,22 @@ lookup_fte_locked(struct mlx5_flow_group *g,
fte_tmp = NULL;
goto out;
}
+
+ nested_down_write_ref_node(&fte_tmp->node, FS_LOCK_CHILD);
+
if (!fte_tmp->node.active) {
+ up_write_ref_node(&fte_tmp->node, false);
+
+ if (take_write)
+ up_write_ref_node(&g->node, false);
+ else
+ up_read_ref_node(&g->node);
+
tree_put_node(&fte_tmp->node, false);
- fte_tmp = NULL;
- goto out;
+
+ return NULL;
}
- nested_down_write_ref_node(&fte_tmp->node, FS_LOCK_CHILD);
out:
if (take_write)
up_write_ref_node(&g->node, false);
