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Date: Mon, 16 Aug 2010 19:03:40 +0200 Message-ID: Subject: Re: 2.6.35+vfs-scale: INFO: suspicious rcu_dereference_check() usage (kernel/exit.c:1387) From: Vegard Nossum To: Nick Piggin Cc: Peter Zijlstra , David Howells , "Paul E. McKenney" , LKML Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2964 Lines: 85 On the third try it will hopefully work. Vegard ---------- Forwarded message ---------- From: Vegard Nossum Date: 16 August 2010 19:01 Subject: Re: 2.6.35+vfs-scale: INFO: suspicious rcu_dereference_check() usage (kernel/exit.c:1387) To: Nick Piggin Cc: Peter Zijlstra , David Howells , "Paul E. McKenney" , LKML Nick Piggin might update his git config because the commits in the vfs-scale tree appear to bear an invalid e-mail address. Please reply to this e-mail instead. Thanks. Vegard ---------- Forwarded message ---------- From: Vegard Nossum Date: 16 August 2010 18:57 Subject: 2.6.35+vfs-scale: INFO: suspicious rcu_dereference_check() usage (kernel/exit.c:1387) To: Nick Piggin Cc: Peter Zijlstra , David Howells , "Paul E. McKenney" , LKML Hi, I was testing your VFS scaling tree*, but I get the following in my dmesg: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- kernel/exit.c:1387 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by bash/2878: #0: (tasklist_lock){.+.+..}, at: [] do_wait+0xb3/0x200 #1: (&(&sighand->siglock)->rlock){-.....}, at: [] wait_consider_task+0x2ca/0xaa3 stack backtrace: Pid: 2878, comm: bash Not tainted 2.6.35-00079-g4067b85 #7 Call Trace: [] lockdep_rcu_dereference+0x9b/0xa6 [] wait_consider_task+0x917/0xaa3 [] ? add_preempt_count+0xc2/0xc9 [] do_wait+0xdb/0x200 [] sys_wait4+0x99/0xd3 [] ? child_wait_callback+0x0/0x5d [] ? might_fault+0x96/0xbc [] compat_sys_wait4+0x8a/0xc1 [] ? might_fault+0xb3/0xbc [] ? might_fault+0x68/0xbc [] ? trace_hardirqs_off_thunk+0x3a/0x3c [] sys32_waitpid+0xb/0xd [] sysenter_dispatch+0x7/0x30 [] ? trace_hardirqs_on_thunk+0x3a/0x3f I don't think it's related to the VFS patches, however, so I added some other (maybe relevant) CCs too. At the time I was simply invoking gcc from bash. Vegard * git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin.git branch vfs-scale -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/