On Mon, Jul 20, 2009 at 02:50:19PM +0800, Li Zefan wrote: > > Commit-ID: 613afbf83298efaead05ebcac23d2285609d7160 > > Gitweb: http://git.kernel.org/tip/613afbf83298efaead05ebcac23d2285609d7160 > > Author: Frederic Weisbecker <fweisbec@xxxxxxxxx> > > AuthorDate: Thu, 16 Jul 2009 15:44:29 +0200 > > Committer: Ingo Molnar <mingo@xxxxxxx> > > CommitDate: Sat, 18 Jul 2009 15:51:44 +0200 > > > > sched: Pull up the might_sleep() check into cond_resched() > > > > might_sleep() is called late-ish in cond_resched(), after the > > need_resched()/preempt enabled/system running tests are > > checked. > > > > It's better to check the sleeps while atomic earlier and not > > depend on some environment datas that reduce the chances to > > detect a problem. > > > > Also define cond_resched_*() helpers as macros, so that the > > FILE/LINE reported in the sleeping while atomic warning > > displays the real origin and not sched.h > > > > I guess it's this patch that causes lots of "BUG" > > BUG: sleeping function called from invalid context at fs/jbd/commit.c:902 > in_atomic(): 0, irqs_disabled(): 0, pid: 64, name: kjournald > INFO: lockdep is turned off. > Pid: 64, comm: kjournald Tainted: GF 2.6.31-rc3-tip #15 > Call Trace: > [<c042cbd1>] __might_sleep+0xda/0xdf > [<c053e9f4>] journal_commit_transaction+0xb03/0xc5f > [<c043ecc4>] ? try_to_del_timer_sync+0x48/0x4f > [<c0541394>] kjournald+0xcf/0x1fe > [<c0448998>] ? autoremove_wake_function+0x0/0x34 > [<c05412c5>] ? kjournald+0x0/0x1fe > [<c0448708>] kthread+0x6b/0x70 > [<c044869d>] ? kthread+0x0/0x70 > [<c040364b>] kernel_thread_helper+0x7/0x10 > BUG: sleeping function called from invalid context at fs/dcache.c:512 > in_atomic(): 0, irqs_disabled(): 0, pid: 2005, name: bash > INFO: lockdep is turned off. > Pid: 2005, comm: bash Tainted: GF 2.6.31-rc3-tip #15 > Call Trace: > [<c042cbd1>] __might_sleep+0xda/0xdf > [<c04cae29>] __shrink_dcache_sb+0x208/0x27a > [<c04cb038>] shrink_dcache_parent+0x2c/0xcf > [<c04f8371>] proc_flush_task+0xa7/0x194 > [<c0437553>] release_task+0x29/0x3b4 > [<c0437fe0>] wait_consider_task+0x702/0xa91 > [<c043844d>] do_wait+0xde/0x276 > [<c0430f6e>] ? default_wake_function+0x0/0x12 > [<c0438672>] sys_wait4+0x8d/0xa6 > [<c04a3c65>] ? might_fault+0x85/0x87 > [<c04386a3>] sys_waitpid+0x18/0x1a > [<c0402ab8>] sysenter_do_call+0x12/0x36 Hm, I can read that in fs/dcache.c:512 /* dentry->d_lock was dropped in prune_one_dentry() */ cond_resched_lock(&dcache_lock); Isn't it a mususe of cond_resched_lock() ? In this case, dcache.c should be fixed. Anyway a generic fix could be the following. Can you tell me if this works for you? Thanks! --- From: Frederic Weisbecker <fweisbec@xxxxxxxxx> Subject: [PATCH] sched: Check if the spinlock is locked in cond_resched_lock() Some uses of cond_resched_lock() might involve an unlocked spinlock, resulting in spurious sleep in atomic warnings. Check whether the spinlock is actually locked and take that into account in the might_sleep() check. Reported-by: Li Zefan <lizf@xxxxxxxxxxxxxx> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> --- diff --git a/include/linux/sched.h b/include/linux/sched.h index cb070dc..2789658 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2294,9 +2294,10 @@ extern int _cond_resched(void); extern int __cond_resched_lock(spinlock_t *lock); -#define cond_resched_lock(lock) ({ \ - __might_sleep(__FILE__, __LINE__, PREEMPT_OFFSET); \ - __cond_resched_lock(lock); \ +#define cond_resched_lock(lock) ({ \ + __might_sleep(__FILE__, __LINE__, spin_is_locked(lock) ? \ + PREEMPT_OFFSET : 0); \ + __cond_resched_lock(lock); \ }) extern int __cond_resched_softirq(void); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html