6.17-stable review patch. If anyone has any objections, please let me know.
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From: Wang Liang wangliang74@huawei.com
[ Upstream commit f584239a9ed25057496bf397c370cc5163dde419 ]
The syzbot report a crash:
Oops: general protection fault, probably for non-canonical address 0xfbd5a5d5a0000003: 0000 [#1] SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdead4ead00000018-0xdead4ead0000001f] CPU: 1 UID: 0 PID: 6949 Comm: syz.0.335 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:smc_diag_msg_common_fill net/smc/smc_diag.c:44 [inline] RIP: 0010:__smc_diag_dump.constprop.0+0x3ca/0x2550 net/smc/smc_diag.c:89 Call Trace: <TASK> smc_diag_dump_proto+0x26d/0x420 net/smc/smc_diag.c:217 smc_diag_dump+0x27/0x90 net/smc/smc_diag.c:234 netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2327 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2442 netlink_dump_start include/linux/netlink.h:341 [inline] smc_diag_handler_dump+0x1f9/0x240 net/smc/smc_diag.c:251 __sock_diag_cmd net/core/sock_diag.c:249 [inline] sock_diag_rcv_msg+0x438/0x790 net/core/sock_diag.c:285 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2614 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668 __sys_sendmsg+0x16d/0x220 net/socket.c:2700 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>
The process like this:
(CPU1) | (CPU2) ---------------------------------|------------------------------- inet_create() | // init clcsock to NULL | sk = sk_alloc() | | // unexpectedly change clcsock | inet_init_csk_locks() | | // add sk to hash table | smc_inet_init_sock() | smc_sk_init() | smc_hash_sk() | | // traverse the hash table | smc_diag_dump_proto | __smc_diag_dump() | // visit wrong clcsock | smc_diag_msg_common_fill() // alloc clcsock | smc_create_clcsk | sock_create_kern |
With CONFIG_DEBUG_LOCK_ALLOC=y, the smc->clcsock is unexpectedly changed in inet_init_csk_locks(). The INET_PROTOSW_ICSK flag is no need by smc, just remove it.
After removing the INET_PROTOSW_ICSK flag, this patch alse revert commit 6fd27ea183c2 ("net/smc: fix lacks of icsk_syn_mss with IPPROTO_SMC") to avoid casting smc_sock to inet_connection_sock.
Reported-by: syzbot+f775be4458668f7d220e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f775be4458668f7d220e Tested-by: syzbot+f775be4458668f7d220e@syzkaller.appspotmail.com Fixes: d25a92ccae6b ("net/smc: Introduce IPPROTO_SMC") Signed-off-by: Wang Liang wangliang74@huawei.com Reviewed-by: Kuniyuki Iwashima kuniyu@google.com Reviewed-by: Eric Dumazet edumazet@google.com Reviewed-by: D. Wythe alibuda@linux.alibaba.com Link: https://patch.msgid.link/20251017024827.3137512-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_inet.c | 13 ------------- 1 file changed, 13 deletions(-)
diff --git a/net/smc/smc_inet.c b/net/smc/smc_inet.c index a944e7dcb8b96..a94084b4a498e 100644 --- a/net/smc/smc_inet.c +++ b/net/smc/smc_inet.c @@ -56,7 +56,6 @@ static struct inet_protosw smc_inet_protosw = { .protocol = IPPROTO_SMC, .prot = &smc_inet_prot, .ops = &smc_inet_stream_ops, - .flags = INET_PROTOSW_ICSK, };
#if IS_ENABLED(CONFIG_IPV6) @@ -104,27 +103,15 @@ static struct inet_protosw smc_inet6_protosw = { .protocol = IPPROTO_SMC, .prot = &smc_inet6_prot, .ops = &smc_inet6_stream_ops, - .flags = INET_PROTOSW_ICSK, }; #endif /* CONFIG_IPV6 */
-static unsigned int smc_sync_mss(struct sock *sk, u32 pmtu) -{ - /* No need pass it through to clcsock, mss can always be set by - * sock_create_kern or smc_setsockopt. - */ - return 0; -} - static int smc_inet_init_sock(struct sock *sk) { struct net *net = sock_net(sk);
/* init common smc sock */ smc_sk_init(net, sk, IPPROTO_SMC); - - inet_csk(sk)->icsk_sync_mss = smc_sync_mss; - /* create clcsock */ return smc_create_clcsk(net, sk, sk->sk_family); }