diff options
author | Shawn Bohrer <sbohrer@rgmadvisors.com> | 2014-09-03 19:13:57 +0200 |
---|---|---|
committer | Roland Dreier <roland@purestorage.com> | 2014-09-19 18:55:42 +0200 |
commit | 87773dd56d5405ac28119fcfadacefd35877c18f (patch) | |
tree | b17f642eebccabe30740f03ccc6e6c9e26fd8948 /drivers/infiniband | |
parent | Linux 3.17-rc2 (diff) | |
download | linux-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.c | 19 |
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); |