| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Mon, 16 Feb 2015 18:49:10 +0100 |
| Subject: fs/aio: simple simple work |
| |
| |BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:768 |
| |in_atomic(): 1, irqs_disabled(): 0, pid: 26, name: rcuos/2 |
| |2 locks held by rcuos/2/26: |
| | #0: (rcu_callback){.+.+..}, at: [<ffffffff810b1a12>] rcu_nocb_kthread+0x1e2/0x380 |
| | #1: (rcu_read_lock_sched){.+.+..}, at: [<ffffffff812acd26>] percpu_ref_kill_rcu+0xa6/0x1c0 |
| |Preemption disabled at:[<ffffffff810b1a93>] rcu_nocb_kthread+0x263/0x380 |
| |Call Trace: |
| | [<ffffffff81582e9e>] dump_stack+0x4e/0x9c |
| | [<ffffffff81077aeb>] __might_sleep+0xfb/0x170 |
| | [<ffffffff81589304>] rt_spin_lock+0x24/0x70 |
| | [<ffffffff811c5790>] free_ioctx_users+0x30/0x130 |
| | [<ffffffff812ace34>] percpu_ref_kill_rcu+0x1b4/0x1c0 |
| | [<ffffffff810b1a93>] rcu_nocb_kthread+0x263/0x380 |
| | [<ffffffff8106e046>] kthread+0xd6/0xf0 |
| | [<ffffffff81591eec>] ret_from_fork+0x7c/0xb0 |
| |
| replace this preempt_disable() friendly swork. |
| |
| Reported-By: Mike Galbraith <umgwanakikbuti@gmail.com> |
| Suggested-by: Benjamin LaHaise <bcrl@kvack.org> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| fs/aio.c | 24 +++++++++++++++++------- |
| 1 file changed, 17 insertions(+), 7 deletions(-) |
| |
| --- a/fs/aio.c |
| +++ b/fs/aio.c |
| @@ -40,6 +40,7 @@ |
| #include <linux/ramfs.h> |
| #include <linux/percpu-refcount.h> |
| #include <linux/mount.h> |
| +#include <linux/swork.h> |
| |
| #include <asm/kmap_types.h> |
| #include <asm/uaccess.h> |
| @@ -115,7 +116,7 @@ struct kioctx { |
| struct page **ring_pages; |
| long nr_pages; |
| |
| - struct work_struct free_work; |
| + struct swork_event free_work; |
| |
| /* |
| * signals when all in-flight requests are done |
| @@ -258,6 +259,7 @@ static int __init aio_setup(void) |
| .mount = aio_mount, |
| .kill_sb = kill_anon_super, |
| }; |
| + BUG_ON(swork_get()); |
| aio_mnt = kern_mount(&aio_fs); |
| if (IS_ERR(aio_mnt)) |
| panic("Failed to create aio fs mount."); |
| @@ -578,9 +580,9 @@ static int kiocb_cancel(struct aio_kiocb |
| return cancel(&kiocb->common); |
| } |
| |
| -static void free_ioctx(struct work_struct *work) |
| +static void free_ioctx(struct swork_event *sev) |
| { |
| - struct kioctx *ctx = container_of(work, struct kioctx, free_work); |
| + struct kioctx *ctx = container_of(sev, struct kioctx, free_work); |
| |
| pr_debug("freeing %p\n", ctx); |
| |
| @@ -599,8 +601,8 @@ static void free_ioctx_reqs(struct percp |
| if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count)) |
| complete(&ctx->rq_wait->comp); |
| |
| - INIT_WORK(&ctx->free_work, free_ioctx); |
| - schedule_work(&ctx->free_work); |
| + INIT_SWORK(&ctx->free_work, free_ioctx); |
| + swork_queue(&ctx->free_work); |
| } |
| |
| /* |
| @@ -608,9 +610,9 @@ static void free_ioctx_reqs(struct percp |
| * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - |
| * now it's safe to cancel any that need to be. |
| */ |
| -static void free_ioctx_users(struct percpu_ref *ref) |
| +static void free_ioctx_users_work(struct swork_event *sev) |
| { |
| - struct kioctx *ctx = container_of(ref, struct kioctx, users); |
| + struct kioctx *ctx = container_of(sev, struct kioctx, free_work); |
| struct aio_kiocb *req; |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| @@ -629,6 +631,14 @@ static void free_ioctx_users(struct perc |
| percpu_ref_put(&ctx->reqs); |
| } |
| |
| +static void free_ioctx_users(struct percpu_ref *ref) |
| +{ |
| + struct kioctx *ctx = container_of(ref, struct kioctx, users); |
| + |
| + INIT_SWORK(&ctx->free_work, free_ioctx_users_work); |
| + swork_queue(&ctx->free_work); |
| +} |
| + |
| static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) |
| { |
| unsigned i, new_nr; |