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Groups > linux.kernel > #1252237
| From | Kamal Mostafa <kamal@canonical.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.13.y-ckt 81/85] IB/uverbs: Fix race between ib_uverbs_open and remove_one |
| Date | 2015-10-21 00:30 +0200 |
| Message-ID | <qlNzR-pi-45@gated-at.bofh.it> (permalink) |
| References | <qlMNr-7E9-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
3.13.11-ckt28 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Yishai Hadas <yishaih@mellanox.com>
commit 35d4a0b63dc0c6d1177d4f532a9deae958f0662c upstream.
Fixes: 2a72f212263701b927559f6850446421d5906c41 ("IB/uverbs: Remove dev_table")
Before this commit there was a device look-up table that was protected
by a spin_lock used by ib_uverbs_open and by ib_uverbs_remove_one. When
it was dropped and container_of was used instead, it enabled the race
with remove_one as dev might be freed just after:
dev = container_of(inode->i_cdev, struct ib_uverbs_device, cdev) but
before the kref_get.
In addition, this buggy patch added some dead code as
container_of(x,y,z) can never be NULL and so dev can never be NULL.
As a result the comment above ib_uverbs_open saying "the open method
will either immediately run -ENXIO" is wrong as it can never happen.
The solution follows Jason Gunthorpe suggestion from below URL:
https://www.mail-archive.com/linux-rdma@vger.kernel.org/msg25692.html
cdev will hold a kref on the parent (the containing structure,
ib_uverbs_device) and only when that kref is released it is
guaranteed that open will never be called again.
In addition, fixes the active count scheme to use an atomic
not a kref to prevent WARN_ON as pointed by above comment
from Jason.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/infiniband/core/uverbs.h | 3 ++-
drivers/infiniband/core/uverbs_main.c | 43 ++++++++++++++++++++++++-----------
2 files changed, 32 insertions(+), 14 deletions(-)
diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index a283274..639557b 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -85,7 +85,7 @@
*/
struct ib_uverbs_device {
- struct kref ref;
+ atomic_t refcount;
int num_comp_vectors;
struct completion comp;
struct device *dev;
@@ -94,6 +94,7 @@ struct ib_uverbs_device {
struct cdev cdev;
struct rb_root xrcd_tree;
struct mutex xrcd_tree_mutex;
+ struct kobject kobj;
};
struct ib_uverbs_event_file {
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 08219fb..2e10ff9 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -127,14 +127,18 @@ static int (*uverbs_ex_cmd_table[])(struct ib_uverbs_file *file,
static void ib_uverbs_add_one(struct ib_device *device);
static void ib_uverbs_remove_one(struct ib_device *device);
-static void ib_uverbs_release_dev(struct kref *ref)
+static void ib_uverbs_release_dev(struct kobject *kobj)
{
struct ib_uverbs_device *dev =
- container_of(ref, struct ib_uverbs_device, ref);
+ container_of(kobj, struct ib_uverbs_device, kobj);
- complete(&dev->comp);
+ kfree(dev);
}
+static struct kobj_type ib_uverbs_dev_ktype = {
+ .release = ib_uverbs_release_dev,
+};
+
static void ib_uverbs_release_event_file(struct kref *ref)
{
struct ib_uverbs_event_file *file =
@@ -298,13 +302,19 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
return context->device->dealloc_ucontext(context);
}
+static void ib_uverbs_comp_dev(struct ib_uverbs_device *dev)
+{
+ complete(&dev->comp);
+}
+
static void ib_uverbs_release_file(struct kref *ref)
{
struct ib_uverbs_file *file =
container_of(ref, struct ib_uverbs_file, ref);
module_put(file->device->ib_dev->owner);
- kref_put(&file->device->ref, ib_uverbs_release_dev);
+ if (atomic_dec_and_test(&file->device->refcount))
+ ib_uverbs_comp_dev(file->device);
kfree(file);
}
@@ -733,9 +743,7 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
int ret;
dev = container_of(inode->i_cdev, struct ib_uverbs_device, cdev);
- if (dev)
- kref_get(&dev->ref);
- else
+ if (!atomic_inc_not_zero(&dev->refcount))
return -ENXIO;
if (!try_module_get(dev->ib_dev->owner)) {
@@ -756,6 +764,7 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
mutex_init(&file->mutex);
filp->private_data = file;
+ kobject_get(&dev->kobj);
return nonseekable_open(inode, filp);
@@ -763,13 +772,16 @@ err_module:
module_put(dev->ib_dev->owner);
err:
- kref_put(&dev->ref, ib_uverbs_release_dev);
+ if (atomic_dec_and_test(&dev->refcount))
+ ib_uverbs_comp_dev(dev);
+
return ret;
}
static int ib_uverbs_close(struct inode *inode, struct file *filp)
{
struct ib_uverbs_file *file = filp->private_data;
+ struct ib_uverbs_device *dev = file->device;
ib_uverbs_cleanup_ucontext(file, file->ucontext);
@@ -777,6 +789,7 @@ static int ib_uverbs_close(struct inode *inode, struct file *filp)
kref_put(&file->async_file->ref, ib_uverbs_release_event_file);
kref_put(&file->ref, ib_uverbs_release_file);
+ kobject_put(&dev->kobj);
return 0;
}
@@ -872,10 +885,11 @@ static void ib_uverbs_add_one(struct ib_device *device)
if (!uverbs_dev)
return;
- kref_init(&uverbs_dev->ref);
+ atomic_set(&uverbs_dev->refcount, 1);
init_completion(&uverbs_dev->comp);
uverbs_dev->xrcd_tree = RB_ROOT;
mutex_init(&uverbs_dev->xrcd_tree_mutex);
+ kobject_init(&uverbs_dev->kobj, &ib_uverbs_dev_ktype);
spin_lock(&map_lock);
devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
@@ -902,6 +916,7 @@ static void ib_uverbs_add_one(struct ib_device *device)
cdev_init(&uverbs_dev->cdev, NULL);
uverbs_dev->cdev.owner = THIS_MODULE;
uverbs_dev->cdev.ops = device->mmap ? &uverbs_mmap_fops : &uverbs_fops;
+ uverbs_dev->cdev.kobj.parent = &uverbs_dev->kobj;
kobject_set_name(&uverbs_dev->cdev.kobj, "uverbs%d", uverbs_dev->devnum);
if (cdev_add(&uverbs_dev->cdev, base, 1))
goto err_cdev;
@@ -932,9 +947,10 @@ err_cdev:
clear_bit(devnum, overflow_map);
err:
- kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
+ if (atomic_dec_and_test(&uverbs_dev->refcount))
+ ib_uverbs_comp_dev(uverbs_dev);
wait_for_completion(&uverbs_dev->comp);
- kfree(uverbs_dev);
+ kobject_put(&uverbs_dev->kobj);
return;
}
@@ -954,9 +970,10 @@ static void ib_uverbs_remove_one(struct ib_device *device)
else
clear_bit(uverbs_dev->devnum - IB_UVERBS_MAX_DEVICES, overflow_map);
- kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
+ if (atomic_dec_and_test(&uverbs_dev->refcount))
+ ib_uverbs_comp_dev(uverbs_dev);
wait_for_completion(&uverbs_dev->comp);
- kfree(uverbs_dev);
+ kobject_put(&uverbs_dev->kobj);
}
static char *uverbs_devnode(struct device *dev, umode_t *mode)
--
1.9.1
--
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[3.13.y-ckt stable] Linux 3.13.11-ckt28 stable review Kamal Mostafa <kamal@canonical.com> - 2015-10-20 23:40 +0200
[PATCH 3.13.y-ckt 73/85] perf hists: Update the column width for the "srcline" sort key Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
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[PATCH 3.13.y-ckt 81/85] IB/uverbs: Fix race between ib_uverbs_open and remove_one Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
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[PATCH 3.13.y-ckt 21/85] iio: event: Remove negative error code from iio_event_poll Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
[PATCH 3.13.y-ckt 72/85] windfarm: decrement client count when unregistering Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
[PATCH 3.13.y-ckt 22/85] NFSv4: don't set SETATTR for O_RDONLY|O_EXCL Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
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[PATCH 3.13.y-ckt 35/85] USB: ftdi_sio: Added custom PID for CustomWare products Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 30/85] xtensa: fix kernel register spilling Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 26/85] drivers: usb: fsl: Workaround for USB erratum-A005275 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 36/85] HID: usbhid: Fix the check for HID_RESET_PENDING in hid_io_error Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
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[PATCH 3.13.y-ckt 31/85] NFS: nfs_set_pgio_error sometimes misses errors Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 44/85] rtlwifi: rtl8192cu: Add new device ID Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 45/85] of/address: Don't loop forever in of_find_matching_node_by_address(). Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 28/85] staging: comedi: adl_pci7x3x: fix digital output on PCI-7230 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 39/85] xfs: Fix xfs_attr_leafblock definition Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 27/85] serial: 8250: don't bind to SMSC IrCC IR port Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 34/85] USB: symbolserial: Use usb_get_serial_port_data Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
[PATCH 3.13.y-ckt 32/85] NFS: Fix a NULL pointer dereference of migration recovery ops for v4.2 client Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
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[PATCH 3.13.y-ckt 16/85] devres: fix devres_get() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 08/85] ARM: OMAP2+: DRA7: clockdomain: change l4per2_7xx_clkdm to SW_WKUP Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 04/85] sctp: fix race on protocol/netns initialization Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 12/85] usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512 bytes Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 14/85] KVM: MMU: fix validation of mmio page fault Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 11/85] PCI: Add VPD function 0 quirk for Intel Ethernet devices Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 10/85] PCI: Add dev_flags bit to access VPD through function 0 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 15/85] auxdisplay: ks0108: fix refcount Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 09/85] mac80211: enable assoc check for mesh interfaces Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
[PATCH 3.13.y-ckt 13/85] serial: 8250_pci: Add support for Pericom PI7C9X795[1248] Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
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