From fc11a9df6cca216bed244e6b69a8d6a892b5e4c4 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 3 Jul 2009 08:44:33 -0500 Subject: [PATCH] core: Do not disable interrupts on RT in res_counter.c commit 08aaf7b5c10c1e497d4a8b2344e380be7c638846 in tip. 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): [] copy_process+0x68d/0x1500 [ 45.228602] softirqs last enabled at (0): [] 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] [] ? print_irqtrace_events+0xd0/0xe0 [ 45.228639] [] __might_sleep+0x113/0x130 [ 45.228646] [] rt_spin_lock+0xa1/0xb0 [ 45.228653] [] res_counter_charge+0x5d/0x130 [ 45.228660] [] __mem_cgroup_try_charge+0x7f/0x180 [ 45.228667] [] mem_cgroup_charge_common+0x57/0x90 [ 45.228674] [] ? ftrace_call+0x5/0x2b [ 45.228680] [] mem_cgroup_newpage_charge+0x5d/0x60 [ 45.228688] [] __do_fault+0x29e/0x4c0 [ 45.228694] [] ? rt_spin_unlock+0x23/0x80 [ 45.228700] [] handle_mm_fault+0x205/0x890 [ 45.228707] [] ? ftrace_call+0x5/0x2b [ 45.228714] [] do_page_fault+0x11e/0x2a0 [ 45.228720] [] page_fault+0x25/0x30 [ 45.228727] [] ? __clear_user+0x3d/0x70 [ 45.228733] [] ? __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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Paul Gortmaker --- kernel/res_counter.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/res_counter.c b/kernel/res_counter.c index c7eaa37..bd325f7 100644 --- a/kernel/res_counter.c +++ b/kernel/res_counter.c @@ -13,6 +13,7 @@ #include #include #include +#include void res_counter_init(struct res_counter *counter, struct res_counter *parent) { @@ -43,7 +44,7 @@ int res_counter_charge(struct res_counter *counter, unsigned long val, struct res_counter *c, *u; *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); ret = res_counter_charge_locked(c, val); @@ -62,7 +63,7 @@ undo: spin_unlock(&u->lock); } done: - local_irq_restore(flags); + local_irq_restore_nort(flags); return ret; } @@ -79,13 +80,13 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val) unsigned long flags; struct res_counter *c; - local_irq_save(flags); + local_irq_save_nort(flags); for (c = counter; c != NULL; c = c->parent) { spin_lock(&c->lock); res_counter_uncharge_locked(c, val); spin_unlock(&c->lock); } - local_irq_restore(flags); + local_irq_restore_nort(flags); } -- 1.7.0.4