@@ -40,9 +40,8 @@ struct ieee802154_local {
int open_count;
/* As in mac80211 slaves list is modified:
- * 1) under the RTNL
- * 2) protected by slaves_mtx;
- * 3) in an RCU manner
+ * 1) under the RTNL;
+ * 2) protected by iflist_mtx.
*
* So atomic readers can use any of this protection methods.
*/
@@ -101,6 +100,7 @@ enum {
enum ieee802154_sdata_state_bits {
SDATA_STATE_RUNNING,
+ SDATA_STATE_REMOVED,
};
/* Slave interface definition.
@@ -669,7 +669,7 @@ ieee802154_if_add(struct ieee802154_local *local, const char *name,
goto err;
mutex_lock(&local->iflist_mtx);
- list_add_tail_rcu(&sdata->list, &local->interfaces);
+ list_add_tail(&sdata->list, &local->interfaces);
mutex_unlock(&local->iflist_mtx);
return ndev;
@@ -683,11 +683,13 @@ void ieee802154_if_remove(struct ieee802154_sub_if_data *sdata)
{
ASSERT_RTNL();
+ if (test_and_set_bit(SDATA_STATE_REMOVED, &sdata->state))
+ return;
+
mutex_lock(&sdata->local->iflist_mtx);
- list_del_rcu(&sdata->list);
+ list_del(&sdata->list);
mutex_unlock(&sdata->local->iflist_mtx);
- synchronize_rcu();
unregister_netdevice(sdata->dev);
}
@@ -697,6 +699,8 @@ void ieee802154_remove_interfaces(struct ieee802154_local *local)
mutex_lock(&local->iflist_mtx);
list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
+ if (test_and_set_bit(SDATA_STATE_REMOVED, &sdata->state))
+ continue;
list_del(&sdata->list);
unregister_netdevice(sdata->dev);
Syzbot has reported the following BUG: kernel BUG at lib/list_debug.c:58! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 UID: 0 PID: 6277 Comm: syz-executor157 Not tainted 6.12.0-rc6-syzkaller-00005-g557329bcecc2 #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__list_del_entry_valid_or_report+0xf4/0x140 lib/list_debug.c:56 Code: e8 a1 7e 00 07 90 0f 0b 48 c7 c7 e0 37 60 8c 4c 89 fe e8 8f 7e 00 07 90 0f 0b 48 c7 c7 40 38 60 8c 4c 89 fe e8 7d 7e 00 07 90 <0f> 0b 48 c7 c7 a0 38 60 8c 4c 89 fe e8 6b 7e 00 07 90 0f 0b 48 c7 RSP: 0018:ffffc9000490f3d0 EFLAGS: 00010246 RAX: 000000000000004e RBX: dead000000000122 RCX: d211eee56bb28d00 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffff88805b278dd8 R08: ffffffff8174a12c R09: 1ffffffff2852f0d R10: dffffc0000000000 R11: fffffbfff2852f0e R12: dffffc0000000000 R13: dffffc0000000000 R14: dead000000000100 R15: ffff88805b278cc0 FS: 0000555572f94380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056262e4a3000 CR3: 0000000078496000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __list_del_entry_valid include/linux/list.h:124 [inline] __list_del_entry include/linux/list.h:215 [inline] list_del_rcu include/linux/rculist.h:157 [inline] ieee802154_if_remove+0x86/0x1e0 net/mac802154/iface.c:687 rdev_del_virtual_intf_deprecated net/ieee802154/rdev-ops.h:24 [inline] ieee802154_del_iface+0x2c0/0x5c0 net/ieee802154/nl-phy.c:323 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2551 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:744 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2607 ___sys_sendmsg net/socket.c:2661 [inline] __sys_sendmsg+0x292/0x380 net/socket.c:2690 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd094c32309 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 19 00 00 90 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 RSP: 002b:00007ffec50063a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd094c32309 RDX: 0000000004000000 RSI: 0000000020000b00 RDI: 0000000000000004 RBP: 00000000000f4240 R08: 0000000000000000 R09: 00000000000000a0 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000161b7 R13: 00007ffec50063bc R14: 00007ffec50063d0 R15: 00007ffec50063c0 </TASK> Since 'ieee802154_remove_interfaces()' and 'ieee802154_if_remove()' may try to process the same 'struct ieee802154_sub_if_data' object concurrently, there are two problems: 1) list of 'struct ieee802154_sub_if_data' objects linked via 'interfaces' field of 'struct ieee802154_local' should remain consistent; 2) 'unregister_netdevice()' should not be called for the same 'struct net_device' concurrently. IIUC RCU can guarantee 1) but not 2), so discard RCU quirks and prefer explicit SDATA_STATE_REMOVED flag used via atomic and fully-ordered 'test_and_set_bit()' to mark 'struct ieee802154_sub_if_data' instance which has entered the reclamation. Reported-by: syzbot+985f827280dc3a6e7e92@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=985f827280dc3a6e7e92 Fixes: b210b18747cb ("mac802154: move interface del handling in iface") Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- net/mac802154/ieee802154_i.h | 6 +++--- net/mac802154/iface.c | 10 +++++++--- 2 files changed, 10 insertions(+), 6 deletions(-)