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author | Shawn Bohrer <sbohrer@rgmadvisors.com> | 2014-09-03 12:13:57 -0500 |
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committer | Roland Dreier <roland@purestorage.com> | 2014-09-19 09:55:42 -0700 |
commit | 87773dd56d5405ac28119fcfadacefd35877c18f (patch) | |
tree | b17f642eebccabe30740f03ccc6e6c9e26fd8948 /include | |
parent | 52addcf9d6669fa439387610bc65c92fa0980cef (diff) | |
download | linux-stable-87773dd56d5405ac28119fcfadacefd35877c18f.tar.gz linux-stable-87773dd56d5405ac28119fcfadacefd35877c18f.tar.bz2 linux-stable-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 'include')
-rw-r--r-- | include/rdma/ib_umem.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h index 1ea0b65c4cfb..a2bf41e0bde9 100644 --- a/include/rdma/ib_umem.h +++ b/include/rdma/ib_umem.h @@ -47,6 +47,7 @@ struct ib_umem { int writable; int hugetlb; struct work_struct work; + struct pid *pid; struct mm_struct *mm; unsigned long diff; struct sg_table sg_head; |