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Michal Kubecek |
944805 |
From: Eric Dumazet <edumazet@google.com>
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Michal Kubecek |
944805 |
Date: Wed, 13 Apr 2022 10:35:41 -0700
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Michal Kubecek |
944805 |
Subject: net/sched: cls_u32: fix netns refcount changes in u32_change()
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Michal Kubecek |
944805 |
Patch-mainline: v5.18-rc4
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Michal Kubecek |
944805 |
Git-commit: 3db09e762dc79584a69c10d74a6b98f89a9979f8
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Michal Kubecek |
944805 |
References: CVE-2022-29581 bsc#1199665
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
We are now able to detect extra put_net() at the moment
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Michal Kubecek |
944805 |
they happen, instead of much later in correct code paths.
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
u32_init_knode() / tcf_exts_init() populates the ->exts.net
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Michal Kubecek |
944805 |
pointer, but as mentioned in tcf_exts_init(),
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Michal Kubecek |
944805 |
the refcount on netns has not been elevated yet.
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
The refcount is taken only once tcf_exts_get_net()
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Michal Kubecek |
944805 |
is called.
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
So the two u32_destroy_key() calls from u32_change()
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Michal Kubecek |
944805 |
are attempting to release an invalid reference on the netns.
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
syzbot report:
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
refcount_t: decrement hit 0; leaking memory.
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Michal Kubecek |
944805 |
WARNING: CPU: 0 PID: 21708 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
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Michal Kubecek |
944805 |
Modules linked in:
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Michal Kubecek |
944805 |
CPU: 0 PID: 21708 Comm: syz-executor.5 Not tainted 5.18.0-rc2-next-20220412-syzkaller #0
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Michal Kubecek |
944805 |
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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Michal Kubecek |
944805 |
RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
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Michal Kubecek |
944805 |
Code: 1d 14 b6 b2 09 31 ff 89 de e8 6d e9 89 fd 84 db 75 e0 e8 84 e5 89 fd 48 c7 c7 40 aa 26 8a c6 05 f4 b5 b2 09 01 e8 e5 81 2e 05 <0f> 0b eb c4 e8 68 e5 89 fd 0f b6 1d e3 b5 b2 09 31 ff 89 de e8 38
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Michal Kubecek |
944805 |
RSP: 0018:ffffc900051af1b0 EFLAGS: 00010286
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Michal Kubecek |
944805 |
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
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Michal Kubecek |
944805 |
RDX: 0000000000040000 RSI: ffffffff8160a0c8 RDI: fffff52000a35e28
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Michal Kubecek |
944805 |
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
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Michal Kubecek |
944805 |
R10: ffffffff81604a9e R11: 0000000000000000 R12: 1ffff92000a35e3b
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Michal Kubecek |
944805 |
R13: 00000000ffffffef R14: ffff8880211a0194 R15: ffff8880577d0a00
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Michal Kubecek |
944805 |
FS: 00007f25d183e700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
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Michal Kubecek |
944805 |
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
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Michal Kubecek |
944805 |
CR2: 00007f19c859c028 CR3: 0000000051009000 CR4: 00000000003506f0
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Michal Kubecek |
944805 |
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
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Michal Kubecek |
944805 |
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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Michal Kubecek |
944805 |
Call Trace:
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Michal Kubecek |
944805 |
<TASK>
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Michal Kubecek |
944805 |
__refcount_dec include/linux/refcount.h:344 [inline]
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Michal Kubecek |
944805 |
refcount_dec include/linux/refcount.h:359 [inline]
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Michal Kubecek |
944805 |
ref_tracker_free+0x535/0x6b0 lib/ref_tracker.c:118
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Michal Kubecek |
944805 |
netns_tracker_free include/net/net_namespace.h:327 [inline]
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Michal Kubecek |
944805 |
put_net_track include/net/net_namespace.h:341 [inline]
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Michal Kubecek |
944805 |
tcf_exts_put_net include/net/pkt_cls.h:255 [inline]
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Michal Kubecek |
944805 |
u32_destroy_key.isra.0+0xa7/0x2b0 net/sched/cls_u32.c:394
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Michal Kubecek |
944805 |
u32_change+0xe01/0x3140 net/sched/cls_u32.c:909
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Michal Kubecek |
944805 |
tc_new_tfilter+0x98d/0x2200 net/sched/cls_api.c:2148
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Michal Kubecek |
944805 |
rtnetlink_rcv_msg+0x80d/0xb80 net/core/rtnetlink.c:6016
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Michal Kubecek |
944805 |
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2495
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Michal Kubecek |
944805 |
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
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Michal Kubecek |
944805 |
netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
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Michal Kubecek |
944805 |
netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1921
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Michal Kubecek |
944805 |
sock_sendmsg_nosec net/socket.c:705 [inline]
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Michal Kubecek |
944805 |
sock_sendmsg+0xcf/0x120 net/socket.c:725
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Michal Kubecek |
944805 |
____sys_sendmsg+0x6e2/0x800 net/socket.c:2413
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Michal Kubecek |
944805 |
___sys_sendmsg+0xf3/0x170 net/socket.c:2467
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Michal Kubecek |
944805 |
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2496
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Michal Kubecek |
944805 |
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
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Michal Kubecek |
944805 |
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
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Michal Kubecek |
944805 |
entry_SYSCALL_64_after_hwframe+0x44/0xae
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Michal Kubecek |
944805 |
RIP: 0033:0x7f25d0689049
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Michal Kubecek |
944805 |
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
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Michal Kubecek |
944805 |
RSP: 002b:00007f25d183e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
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Michal Kubecek |
944805 |
RAX: ffffffffffffffda RBX: 00007f25d079c030 RCX: 00007f25d0689049
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Michal Kubecek |
944805 |
RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000005
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Michal Kubecek |
944805 |
RBP: 00007f25d06e308d R08: 0000000000000000 R09: 0000000000000000
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Michal Kubecek |
944805 |
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
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Michal Kubecek |
944805 |
R13: 00007ffd0b752e3f R14: 00007f25d183e300 R15: 0000000000022000
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Michal Kubecek |
944805 |
</TASK>
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
Fixes: 35c55fc156d8 ("cls_u32: use tcf_exts_get_net() before call_rcu()")
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Michal Kubecek |
944805 |
Signed-off-by: Eric Dumazet <edumazet@google.com>
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Michal Kubecek |
944805 |
Reported-by: syzbot <syzkaller@googlegroups.com>
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Michal Kubecek |
944805 |
Cc: Cong Wang <xiyou.wangcong@gmail.com>
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Michal Kubecek |
944805 |
Cc: Jiri Pirko <jiri@resnulli.us>
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Michal Kubecek |
944805 |
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
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Michal Kubecek |
944805 |
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Michal Kubecek |
944805 |
Acked-by: Michal Kubecek <mkubecek@suse.cz>
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
---
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Michal Kubecek |
944805 |
net/sched/cls_u32.c | 16 ++++++++++------
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Michal Kubecek |
944805 |
1 file changed, 10 insertions(+), 6 deletions(-)
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
--- a/net/sched/cls_u32.c
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Michal Kubecek |
944805 |
+++ b/net/sched/cls_u32.c
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Michal Kubecek |
944805 |
@@ -398,14 +398,19 @@ static int u32_init(struct tcf_proto *tp)
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Michal Kubecek |
944805 |
return 0;
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Michal Kubecek |
944805 |
}
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
-static int u32_destroy_key(struct tc_u_knode *n, bool free_pf)
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Michal Kubecek |
944805 |
+static void __u32_destroy_key(struct tc_u_knode *n)
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Michal Kubecek |
944805 |
{
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Michal Kubecek |
944805 |
struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
tcf_exts_destroy(&n->exts);
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Michal Kubecek |
944805 |
- tcf_exts_put_net(&n->exts);
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Michal Kubecek |
944805 |
if (ht && --ht->refcnt == 0)
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Michal Kubecek |
944805 |
kfree(ht);
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Michal Kubecek |
944805 |
+ kfree(n);
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Michal Kubecek |
944805 |
+}
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Michal Kubecek |
944805 |
+
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Michal Kubecek |
944805 |
+static void u32_destroy_key(struct tc_u_knode *n, bool free_pf)
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Michal Kubecek |
944805 |
+{
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Michal Kubecek |
944805 |
+ tcf_exts_put_net(&n->exts);
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Michal Kubecek |
944805 |
#ifdef CONFIG_CLS_U32_PERF
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Michal Kubecek |
944805 |
if (free_pf)
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Michal Kubecek |
944805 |
free_percpu(n->pf);
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Michal Kubecek |
944805 |
@@ -414,8 +419,7 @@ static int u32_destroy_key(struct tc_u_knode *n, bool free_pf)
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Michal Kubecek |
944805 |
if (free_pf)
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Michal Kubecek |
944805 |
free_percpu(n->pcpu_success);
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Michal Kubecek |
944805 |
#endif
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Michal Kubecek |
944805 |
- kfree(n);
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Michal Kubecek |
944805 |
- return 0;
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Michal Kubecek |
944805 |
+ __u32_destroy_key(n);
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Michal Kubecek |
944805 |
}
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
/* u32_delete_key_rcu should be called when free'ing a copied
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Michal Kubecek |
944805 |
@@ -918,13 +922,13 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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Michal Kubecek |
944805 |
tca[TCA_RATE], ovr, extack);
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
if (err) {
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Michal Kubecek |
944805 |
- u32_destroy_key(new, false);
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Michal Kubecek |
944805 |
+ __u32_destroy_key(new);
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Michal Kubecek |
944805 |
return err;
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Michal Kubecek |
944805 |
}
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Michal Kubecek |
944805 |
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Michal Kubecek |
944805 |
err = u32_replace_hw_knode(tp, new, flags, extack);
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Michal Kubecek |
944805 |
if (err) {
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Michal Kubecek |
944805 |
- u32_destroy_key(new, false);
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Michal Kubecek |
944805 |
+ __u32_destroy_key(new);
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Michal Kubecek |
944805 |
return err;
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Michal Kubecek |
944805 |
}
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Michal Kubecek |
944805 |
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