From 50b5d6ad63821cea324a5a7a19854d4de1a0a819 Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Thu, 6 May 2010 00:56:07 -0700 Subject: sctp: Fix a race between ICMP protocol unreachable and connect() ICMP protocol unreachable handling completely disregarded the fact that the user may have locked the socket. It proceeded to destroy the association, even though the user may have held the lock and had a ref on the association. This resulted in the following: Attempt to release alive inet socket f6afcc00 ========================= [ BUG: held lock freed! ] ------------------------- somenu/2672 is freeing memory f6afcc00-f6afcfff, with a lock still held there! (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c 1 lock held by somenu/2672: #0: (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c stack backtrace: Pid: 2672, comm: somenu Not tainted 2.6.32-telco #55 Call Trace: [] ? printk+0xf/0x11 [] debug_check_no_locks_freed+0xce/0xff [] kmem_cache_free+0x21/0x66 [] __sk_free+0x9d/0xab [] sk_free+0x1c/0x1e [] sctp_association_put+0x32/0x89 [] __sctp_connect+0x36d/0x3f4 [] ? sctp_connect+0x13/0x4c [] ? autoremove_wake_function+0x0/0x33 [] sctp_connect+0x31/0x4c [] inet_dgram_connect+0x4b/0x55 [] sys_connect+0x54/0x71 [] ? lock_release_non_nested+0x88/0x239 [] ? might_fault+0x42/0x7c [] ? might_fault+0x42/0x7c [] sys_socketcall+0x6d/0x178 [] ? trace_hardirqs_on_thunk+0xc/0x10 [] syscall_call+0x7/0xb This was because the sctp_wait_for_connect() would aqcure the socket lock and then proceed to release the last reference count on the association, thus cause the fully destruction path to finish freeing the socket. The simplest solution is to start a very short timer in case the socket is owned by user. When the timer expires, we can do some verification and be able to do the release properly. Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/net/sctp/structs.h') diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 597f8e2..219043a 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1010,6 +1010,9 @@ struct sctp_transport { /* Heartbeat timer is per destination. */ struct timer_list hb_timer; + /* Timer to handle ICMP proto unreachable envets */ + struct timer_list proto_unreach_timer; + /* Since we're using per-destination retransmission timers * (see above), we're also using per-destination "transmitted" * queues. This probably ought to be a private struct -- cgit v1.1