| From: Ingo Molnar <mingo@elte.hu> |
| Date: Fri, 3 Jul 2009 08:44:33 -0500 |
| Subject: core: Do not disable interrupts on RT in res_counter.c |
| |
| Frederic Weisbecker reported this warning: |
| |
| [ 45.228562] BUG: sleeping function called from invalid context at kernel/rtmutex.c:683 |
| [ 45.228571] in_atomic(): 0, irqs_disabled(): 1, pid: 4290, name: ntpdate |
| [ 45.228576] INFO: lockdep is turned off. |
| [ 45.228580] irq event stamp: 0 |
| [ 45.228583] hardirqs last enabled at (0): [<(null)>] (null) |
| [ 45.228589] hardirqs last disabled at (0): [<ffffffff8025449d>] copy_process+0x68d/0x1500 |
| [ 45.228602] softirqs last enabled at (0): [<ffffffff8025449d>] copy_process+0x68d/0x1500 |
| [ 45.228609] softirqs last disabled at (0): [<(null)>] (null) |
| [ 45.228617] Pid: 4290, comm: ntpdate Tainted: G W 2.6.29-rc4-rt1-tip #1 |
| [ 45.228622] Call Trace: |
| [ 45.228632] [<ffffffff8027dfb0>] ? print_irqtrace_events+0xd0/0xe0 |
| [ 45.228639] [<ffffffff8024cd73>] __might_sleep+0x113/0x130 |
| [ 45.228646] [<ffffffff8077c811>] rt_spin_lock+0xa1/0xb0 |
| [ 45.228653] [<ffffffff80296a3d>] res_counter_charge+0x5d/0x130 |
| [ 45.228660] [<ffffffff802fb67f>] __mem_cgroup_try_charge+0x7f/0x180 |
| [ 45.228667] [<ffffffff802fc407>] mem_cgroup_charge_common+0x57/0x90 |
| [ 45.228674] [<ffffffff80212096>] ? ftrace_call+0x5/0x2b |
| [ 45.228680] [<ffffffff802fc49d>] mem_cgroup_newpage_charge+0x5d/0x60 |
| [ 45.228688] [<ffffffff802d94ce>] __do_fault+0x29e/0x4c0 |
| [ 45.228694] [<ffffffff8077c843>] ? rt_spin_unlock+0x23/0x80 |
| [ 45.228700] [<ffffffff802db8b5>] handle_mm_fault+0x205/0x890 |
| [ 45.228707] [<ffffffff80212096>] ? ftrace_call+0x5/0x2b |
| [ 45.228714] [<ffffffff8023495e>] do_page_fault+0x11e/0x2a0 |
| [ 45.228720] [<ffffffff8077e5a5>] page_fault+0x25/0x30 |
| [ 45.228727] [<ffffffff8043e1ed>] ? __clear_user+0x3d/0x70 |
| [ 45.228733] [<ffffffff8043e1d1>] ? __clear_user+0x21/0x70 |
| |
| The reason is the raw IRQ flag use of kernel/res_counter.c. |
| |
| The irq flags tricks there seem a bit pointless: it cannot protect the |
| c->parent linkage because local_irq_save() is only per CPU. |
| |
| So replace it with _nort(). This code needs a second look. |
| |
| Reported-by: Frederic Weisbecker <fweisbec@gmail.com> |
| Signed-off-by: Ingo Molnar <mingo@elte.hu> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| |
| --- |
| kernel/res_counter.c | 8 ++++---- |
| 1 file changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/kernel/res_counter.c |
| +++ b/kernel/res_counter.c |
| @@ -49,7 +49,7 @@ static int __res_counter_charge(struct r |
| |
| r = ret = 0; |
| *limit_fail_at = NULL; |
| - local_irq_save(flags); |
| + local_irq_save_nort(flags); |
| for (c = counter; c != NULL; c = c->parent) { |
| spin_lock(&c->lock); |
| r = res_counter_charge_locked(c, val, force); |
| @@ -69,7 +69,7 @@ static int __res_counter_charge(struct r |
| spin_unlock(&u->lock); |
| } |
| } |
| - local_irq_restore(flags); |
| + local_irq_restore_nort(flags); |
| |
| return ret; |
| } |
| @@ -103,7 +103,7 @@ u64 res_counter_uncharge_until(struct re |
| struct res_counter *c; |
| u64 ret = 0; |
| |
| - local_irq_save(flags); |
| + local_irq_save_nort(flags); |
| for (c = counter; c != top; c = c->parent) { |
| u64 r; |
| spin_lock(&c->lock); |
| @@ -112,7 +112,7 @@ u64 res_counter_uncharge_until(struct re |
| ret = r; |
| spin_unlock(&c->lock); |
| } |
| - local_irq_restore(flags); |
| + local_irq_restore_nort(flags); |
| return ret; |
| } |
| |
