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authorShawn Bohrer <sbohrer@rgmadvisors.com>2014-09-03 12:13:57 -0500
committerRoland Dreier <roland@purestorage.com>2014-09-19 09:55:42 -0700
commit87773dd56d5405ac28119fcfadacefd35877c18f (patch)
treeb17f642eebccabe30740f03ccc6e6c9e26fd8948 /include
parent52addcf9d6669fa439387610bc65c92fa0980cef (diff)
downloadlinux-linaro-stable-87773dd56d5405ac28119fcfadacefd35877c18f.tar.gz
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.h1
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;