On Thu, Jun 25, 2009 at 2:07 PM, Vivek Satpute<vivek@xxxxxxxxxxxxxx> wrote: > Kernel panic's and reboot while doing network operations such ifconfig > and ping on MIPS architecture after RT-patches applied. > > In case of CONFIG_PREEMPT_RT, after releasing the lock with > "spin_unlock", context switch might occur before enabling the bottom > half with local_bh_enable and this causes the kernel to panic. > The issue is resolved by releasing the lock afer acquiring the mutex > using spin_unlock_bh. > > Tested the fix on MIPS and X86 architecture. > > Signed-off-by: Vivek Satpute <vivek@xxxxxxxxxxxxxx> > --- > net/core/sock.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > Index: linux-2.6.28.4/net/core/sock.c > =================================================================== > --- linux-2.6.28.4.orig/net/core/sock.c > +++ linux-2.6.28.4/net/core/sock.c > @@ -1752,12 +1752,20 @@ void lock_sock_nested(struct sock *sk, i > if (sk->sk_lock.owned) > __lock_sock(sk); > sk->sk_lock.owned = 1; > + > +#ifndef CONFIG_PREEMPT_RT > spin_unlock(&sk->sk_lock.slock); > +#endif > /* > * The sk_lock has mutex_lock() semantics here: > */ > mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_); > + > +#ifdef CONFIG_PREEMPT_RT > + spin_unlock_bh(&sk->sk_lock.slock); > +#else > local_bh_enable(); > +#endif > } > I don't think you should move the unlock after the mutex_acquire(). I guess that this will lead to false positive lockdep warnings. Anyway, I wonder why using spin_unlock_bh() is fixing the problem that you are having. Do you have more context about the problem or maybe an Oops or so? Thanks, Jan > EXPORT_SYMBOL(lock_sock_nested); > > > > > Thanks and Regards, > Vivek Satpute > System Software Engineer > LinSysSoft Technologies, Pune > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
