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authorShawn Bohrer <sbohrer@rgmadvisors.com>2014-09-03 19:13:57 +0200
committerRoland Dreier <roland@purestorage.com>2014-09-19 18:55:42 +0200
commit87773dd56d5405ac28119fcfadacefd35877c18f (patch)
treeb17f642eebccabe30740f03ccc6e6c9e26fd8948 /drivers/infiniband
parentLinux 3.17-rc2 (diff)
downloadlinux-87773dd56d5405ac28119fcfadacefd35877c18f.tar.xz
linux-87773dd56d5405ac28119fcfadacefd35877c18f.zip
IB: ib_umem_release() should decrement mm->pinned_vm from ib_umem_get
In debugging an application that receives -ENOMEM from ib_reg_mr(), I found that ib_umem_get() can fail because the pinned_vm count has wrapped causing it to always be larger than the lock limit even with RLIMIT_MEMLOCK set to RLIM_INFINITY. The wrapping of pinned_vm occurs because the process that calls ib_reg_mr() will have its mm->pinned_vm count incremented. Later a different process with a different mm_struct than the one that allocated the ib_umem struct ends up releasing it which results in decrementing the new processes mm->pinned_vm count past zero and wrapping. I'm not entirely sure what circumstances cause a different process to release the ib_umem than the one that allocated it but the kernel stack trace of the freeing process from my situation looks like the following: Call Trace: [<ffffffff814d64b1>] dump_stack+0x19/0x1b [<ffffffffa0b522a5>] ib_umem_release+0x1f5/0x200 [ib_core] [<ffffffffa0b90681>] mlx4_ib_destroy_qp+0x241/0x440 [mlx4_ib] [<ffffffffa0b4d93c>] ib_destroy_qp+0x12c/0x170 [ib_core] [<ffffffffa0cc7129>] ib_uverbs_close+0x259/0x4e0 [ib_uverbs] [<ffffffff81141cba>] __fput+0xba/0x240 [<ffffffff81141e4e>] ____fput+0xe/0x10 [<ffffffff81060894>] task_work_run+0xc4/0xe0 [<ffffffff810029e5>] do_notify_resume+0x95/0xa0 [<ffffffff814e3dd0>] int_signal+0x12/0x17 The following patch fixes the issue by storing the pid struct of the process that calls ib_umem_get() so that ib_umem_release and/or ib_umem_account() can properly decrement the pinned_vm count of the correct mm_struct. Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com> Reviewed-by: Shachar Raindel <raindel@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/core/umem.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index a3a2e9c1639b..df0c4f605a21 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -105,6 +105,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
umem->length = size;
umem->offset = addr & ~PAGE_MASK;
umem->page_size = PAGE_SIZE;
+ umem->pid = get_task_pid(current, PIDTYPE_PID);
/*
* We ask for writable memory if any access flags other than
* "remote read" are set. "Local write" and "remote write"
@@ -198,6 +199,7 @@ out:
if (ret < 0) {
if (need_release)
__ib_umem_release(context->device, umem, 0);
+ put_pid(umem->pid);
kfree(umem);
} else
current->mm->pinned_vm = locked;
@@ -230,15 +232,19 @@ void ib_umem_release(struct ib_umem *umem)
{
struct ib_ucontext *context = umem->context;
struct mm_struct *mm;
+ struct task_struct *task;
unsigned long diff;
__ib_umem_release(umem->context->device, umem, 1);
- mm = get_task_mm(current);
- if (!mm) {
- kfree(umem);
- return;
- }
+ task = get_pid_task(umem->pid, PIDTYPE_PID);
+ put_pid(umem->pid);
+ if (!task)
+ goto out;
+ mm = get_task_mm(task);
+ put_task_struct(task);
+ if (!mm)
+ goto out;
diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
@@ -262,9 +268,10 @@ void ib_umem_release(struct ib_umem *umem)
} else
down_write(&mm->mmap_sem);
- current->mm->pinned_vm -= diff;
+ mm->pinned_vm -= diff;
up_write(&mm->mmap_sem);
mmput(mm);
+out:
kfree(umem);
}
EXPORT_SYMBOL(ib_umem_release);