The patch titled
lockdep: fix sk->sk_callback_lock locking
has been added to the -mm tree. Its filename is
lockdep-fix-sk-sk_callback_lock-locking.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: lockdep: fix sk->sk_callback_lock locking
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
=========================================================
[ INFO: possible irq lock inversion dependency detected ]
2.6.19-rc6 #4
---------------------------------------------------------
nc/1854 just changed the state of lock:
(af_callback_keys + sk->sk_family#2){-.-?}, at: [<c0268a7f>] sock_def_error_report+0x1f/0x90
but this lock was taken by another, soft-irq-safe lock in the past:
(slock-AF_INET){-+..}
and interrupts could create inverse lock ordering between them.
stack backtrace:
[<c0103f36>] show_trace_log_lvl+0x26/0x40
[<c010406b>] show_trace+0x1b/0x20
[<c01049e4>] dump_stack+0x24/0x30
[<c013738c>] print_irq_inversion_bug+0x10c/0x130
[<c01374f2>] check_usage_backwards+0x42/0x50
[<c0137912>] mark_lock+0x312/0x620
[<c0138925>] __lock_acquire+0x4c5/0xcb0
[<c0139499>] lock_acquire+0x69/0x90
[<c02ddc49>] _read_lock+0x39/0x50
[<c026778c>] sock_def_wakeup+0x1c/0x60
[<c02b7d73>] inet_shutdown+0x93/0xf0
[<c02648d2>] sys_shutdown+0x32/0x60
[<c0266284>] sys_socketcall+0x1d4/0x260
[<c01031f3>] syscall_call+0x7/0xb
=======================
stack backtrace:
[<c0103f36>] show_trace_log_lvl+0x26/0x40
[<c010406b>] show_trace+0x1b/0x20
[<c01049e4>] dump_stack+0x24/0x30
[<c013738c>] print_irq_inversion_bug+0x10c/0x130
[<c01374f2>] check_usage_backwards+0x42/0x50
[<c0137912>] mark_lock+0x312/0x620
[<c0138925>] __lock_acquire+0x4c5/0xcb0
[<c0139499>] lock_acquire+0x69/0x90
[<c02ddc59>] _read_lock+0x39/0x50
[<c0268a7f>] sock_def_error_report+0x1f/0x90
[<c029b968>] tcp_disconnect+0x318/0x490
[<c02b9110>] inet_stream_connect+0x220/0x260
[<c0264adb>] sys_connect+0x6b/0x90
[<c026614f>] sys_socketcall+0x9f/0x260
[<c01031f3>] syscall_call+0x7/0xb
=======================
sk->sk_callback_lock is usually only read locked from softirq context
however it seems lockdep found two spots that are reachable from process
context, thus creating the possibility of a deadlock.
For now fix these two call sites with manual disabling of softirqs; if
more of these sites are found we might consider changing the read_lock() to
read_lock_bh().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Martin Josefsson <gandalf@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
net/ipv4/af_inet.c | 2 ++
net/ipv4/tcp.c | 2 ++
2 files changed, 4 insertions(+)
diff -puN net/ipv4/af_inet.c~lockdep-fix-sk-sk_callback_lock-locking net/ipv4/af_inet.c
--- a/net/ipv4/af_inet.c~lockdep-fix-sk-sk_callback_lock-locking
+++ a/net/ipv4/af_inet.c
@@ -731,7 +731,9 @@ int inet_shutdown(struct socket *sock, i
}
/* Wake up anyone sleeping in poll. */
+ local_bh_disable();
sk->sk_state_change(sk);
+ local_bh_enable();
release_sock(sk);
return err;
}
diff -puN net/ipv4/tcp.c~lockdep-fix-sk-sk_callback_lock-locking net/ipv4/tcp.c
--- a/net/ipv4/tcp.c~lockdep-fix-sk-sk_callback_lock-locking
+++ a/net/ipv4/tcp.c
@@ -1775,7 +1775,9 @@ int tcp_disconnect(struct sock *sk, int
BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
+ local_bh_disable();
sk->sk_error_report(sk);
+ local_bh_enable();
return err;
}
_
Patches currently in -mm which might be from a.p.zijlstra@xxxxxxxxx are
origin.patch
git-net.patch
lockdep-fix-sk-sk_callback_lock-locking.patch
grab-swap-token-reordered.patch
new-scheme-to-preempt-swap-token.patch
new-scheme-to-preempt-swap-token-tidy.patch
mm-arch-do_page_fault-vs-in_atomic.patch
mm-pagefault_disableenable.patch
mm-pagefault_disableenable-s390-fix.patch
mm-kummap_atomic-vs-in_atomic.patch
mm-call-into-direct-reclaim-without-pf_memalloc-set.patch
mm-cleanup-and-document-reclaim-recursion.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets-tidy.patch
lockdep-fix-ide-proc-interaction.patch
lockdep-annotate-bcsp-driver.patch
lockdep-print-current-locks-on-in_atomic-warnings.patch
lockdep-name-some-old-style-locks.patch
debug-workqueue-locking-sanity.patch
debug-workqueue-locking-sanity-fix.patch
tty-signal-tty-locking.patch
tty-signal-tty-locking-3270-fix.patch
do_task_stat-dont-take-tty_mutex.patch
do_acct_process-dont-take-tty_mutex.patch
sys_unshare-remove-a-broken-clone_sighand-code.patch
remove-the-old-bd_mutex-lockdep-annotation.patch
new-bd_mutex-lockdep-annotation.patch
remove-lock_key-approach-to-managing-nested-bd_mutex-locks.patch
simplify-some-aspects-of-bd_mutex-nesting.patch
use-mutex_lock_nested-for-bd_mutex-to-avoid-lockdep-warning.patch
avoid-lockdep-warning-in-md.patch
bdev-fix-bd_part_count-leak.patch
lockdep-annotate-nfsd4-recover-code.patch
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