[PATCH net] inet: control sockets should not use current thread task_frag

[PATCH net] inet: control sockets should not use current thread task_frag

[Eric Dumazet]

Because ICMP handlers run from softirq contexts,
they must not use current thread task_frag.

Previously, all sockets allocated by inet_ctl_sock_create()
would use the per-socket page fragment, with no chance of
recursion.

Fixes: 98123866fcf3 ("Treewide: Stop corrupting socket's task_frag")
Reported-by: syzbot+bebc6f1acdf4cbb79b03@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Guillaume Nault <gnault@redhat.com>
Cc: Benjamin Coddington <bcodding@redhat.com>
---
 net/ipv4/af_inet.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index ab4a06be489b5d410cec603bf56248d31dbc90dd..6c0ec27899431eb56e2f9d0c3a936b77f44ccaca 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1665,6 +1665,7 @@ int inet_ctl_sock_create(struct sock **sk, unsigned short family,
 	if (rc == 0) {
 		*sk = sock->sk;
 		(*sk)->sk_allocation = GFP_ATOMIC;
+		(*sk)->sk_use_task_frag = false;
 		/*
 		 * Unhash it so that IP input processing does not even see it,
 		 * we do not wish this socket to see incoming packets.
-- 
2.39.0.314.g84b9a713c41-goog

Re: [PATCH net] inet: control sockets should not use current thread task_frag

[Guillaume Nault]

On Tue, Jan 03, 2023 at 07:27:36PM +0000, Eric Dumazet wrote:
> Because ICMP handlers run from softirq contexts,
> they must not use current thread task_frag.
> 
> Previously, all sockets allocated by inet_ctl_sock_create()
> would use the per-socket page fragment, with no chance of
> recursion.

Acked-by: Guillaume Nault <gnault@redhat.com>

Thanks for the fix!

Re: [PATCH net] inet: control sockets should not use current thread task_frag

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Tue,  3 Jan 2023 19:27:36 +0000 you wrote:
> Because ICMP handlers run from softirq contexts,
> they must not use current thread task_frag.
> 
> Previously, all sockets allocated by inet_ctl_sock_create()
> would use the per-socket page fragment, with no chance of
> recursion.
> 
> [...]

Here is the summary with links:
  - [net] inet: control sockets should not use current thread task_frag
    https://git.kernel.org/netdev/net/c/1ac885574470

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html