aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/core
diff options
context:
space:
mode:
authorJason Gunthorpe <jgg@mellanox.com>2018-07-10 20:55:13 -0600
committerJason Gunthorpe <jgg@mellanox.com>2018-07-25 14:21:21 -0600
commit3df593bfe6455f28cda879be8299b30b8601ce3b (patch)
treeeeb2952882d1de83c3d0b566c3c0341bfbfcf452 /drivers/infiniband/core
parentnet/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() calls (diff)
downloadlinux-dev-3df593bfe6455f28cda879be8299b30b8601ce3b.tar.xz
linux-dev-3df593bfe6455f28cda879be8299b30b8601ce3b.zip
IB/uverbs: Get rid of null_obj_type
If the method fails after calling rdma_explicit_destroy (eg if copy_to_user faults) then it will trigger a kernel oops: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 PGD 800000000548d067 P4D 800000000548d067 PUD 54a0067 PMD 0 SMP PTI CPU: 0 PID: 359 Comm: ibv_rc_pingpong Not tainted 4.18.0-rc1+ #28 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 RIP: 0010: (null) Code: Bad RIP value. RSP: 0018:ffffc900001a3bf0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88000603bd00 RCX: 0000000000000003 RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff88000603bd00 RBP: 0000000000000001 R08: ffffc900001a3cf8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900001a3cf0 R13: 0000000000000000 R14: ffffc900001a3cf0 R15: 0000000000000000 FS: 00007fb00dda8700(0000) GS:ffff880007c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000000548e004 CR4: 00000000003606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? rdma_lookup_put_uobject+0x22/0x50 [ib_uverbs] ? uverbs_finalize_object+0x3b/0x60 [ib_uverbs] ? uverbs_finalize_attrs+0x128/0x140 [ib_uverbs] ? ib_uverbs_cmd_verbs+0x698/0x7c0 [ib_uverbs] ? find_held_lock+0x2d/0x90 ? __might_fault+0x39/0x90 ? ib_uverbs_ioctl+0x111/0x1f0 [ib_uverbs] ? do_vfs_ioctl+0xa0/0x6d0 ? trace_hardirqs_on_caller+0xed/0x180 ? _raw_spin_unlock_irq+0x24/0x40 ? syscall_trace_enter+0x138/0x1d0 ? ksys_ioctl+0x35/0x60 ? __x64_sys_ioctl+0x11/0x20 ? do_syscall_64+0x5b/0x1c0 ? entry_SYSCALL_64_after_hwframe+0x49/0xbe This is because the type was replaced with the null_type during explicit destroy that cannot complete the destruction. One of the side effects of replacing the type is to make the object handle totally unreachable - so no other command could attempt to use it, even though it remains on the uboject list. We can get the same end result by just fully destroying the object inside rdma_explicit_destroy and leaving the caller the residual kref for the uobj with no attached HW object, and no presence in the ubojects list. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Diffstat (limited to 'drivers/infiniband/core')
-rw-r--r--drivers/infiniband/core/rdma_core.c41
1 files changed, 9 insertions, 32 deletions
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index 847c6a2f1346..aed7cc2a9e86 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -439,12 +439,17 @@ static int __must_check _rdma_remove_commit_uobject(struct ib_uobject *uobj,
struct ib_uverbs_file *ufile = uobj->ufile;
int ret;
+ if (!uobj->object)
+ return 0;
+
ret = uobj->type->type_class->remove_commit(uobj, why);
if (ib_is_destroy_retryable(ret, why, uobj)) {
/* We couldn't remove the object, so just unlock the uobject */
atomic_set(&uobj->usecnt, 0);
uobj->type->type_class->lookup_put(uobj, true);
} else {
+ uobj->object = NULL;
+
mutex_lock(&ufile->uobjects_lock);
list_del(&uobj->list);
mutex_unlock(&ufile->uobjects_lock);
@@ -459,35 +464,13 @@ static int __must_check _rdma_remove_commit_uobject(struct ib_uobject *uobj,
int __must_check rdma_remove_commit_uobject(struct ib_uobject *uobj)
{
int ret;
- struct ib_uverbs_file *ufile = uobj->ufile;
- /* put the ref count we took at lookup_get */
- uverbs_uobject_put(uobj);
- /* Cleanup is running. Calling this should have been impossible */
- if (!down_read_trylock(&ufile->cleanup_rwsem)) {
- WARN(true, "ib_uverbs: Cleanup is running while removing an uobject\n");
- return 0;
- }
- assert_uverbs_usecnt(uobj, true);
- ret = _rdma_remove_commit_uobject(uobj, RDMA_REMOVE_DESTROY);
-
- up_read(&ufile->cleanup_rwsem);
+ ret = rdma_explicit_destroy(uobj);
+ /* Pairs with the lookup_get done by the caller */
+ rdma_lookup_put_uobject(uobj, true);
return ret;
}
-static int null_obj_type_class_remove_commit(struct ib_uobject *uobj,
- enum rdma_remove_reason why)
-{
- return 0;
-}
-
-static const struct uverbs_obj_type null_obj_type = {
- .type_class = &((const struct uverbs_obj_type_class){
- .remove_commit = null_obj_type_class_remove_commit,
- /* be cautious */
- .needs_kfree_rcu = true}),
-};
-
int rdma_explicit_destroy(struct ib_uobject *uobject)
{
int ret;
@@ -499,14 +482,8 @@ int rdma_explicit_destroy(struct ib_uobject *uobject)
return 0;
}
assert_uverbs_usecnt(uobject, true);
- ret = uobject->type->type_class->remove_commit(uobject,
- RDMA_REMOVE_DESTROY);
- if (ret)
- goto out;
-
- uobject->type = &null_obj_type;
+ ret = _rdma_remove_commit_uobject(uobject, RDMA_REMOVE_DESTROY);
-out:
up_read(&ufile->cleanup_rwsem);
return ret;
}