diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2024-02-22 13:23:46 -0800 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2024-02-26 16:58:11 -0400 |
| commit | fde372df96afddcda3ec94944351f2a14f7cd98d (patch) | |
| tree | 47f1fb9508f90bc119c8b6dac6a059806d0de3fb /drivers/iommu | |
| parent | aeb004c0cd6958e910123a1607634401009c9539 (diff) | |
iommufd/selftest: Fix mock_dev_num bug
Syzkaller reported the following bug:
sysfs: cannot create duplicate filename '/devices/iommufd_mock4'
Call Trace:
sysfs_warn_dup+0x71/0x90
sysfs_create_dir_ns+0x1ee/0x260
? sysfs_create_mount_point+0x80/0x80
? spin_bug+0x1d0/0x1d0
? do_raw_spin_unlock+0x54/0x220
kobject_add_internal+0x221/0x970
kobject_add+0x11c/0x1e0
? lockdep_hardirqs_on_prepare+0x273/0x3e0
? kset_create_and_add+0x160/0x160
? kobject_put+0x5d/0x390
? bus_get_dev_root+0x4a/0x60
? kobject_put+0x5d/0x390
device_add+0x1d5/0x1550
? __fw_devlink_link_to_consumers.isra.0+0x1f0/0x1f0
? __init_waitqueue_head+0xcb/0x150
iommufd_test+0x462/0x3b60
? lock_release+0x1fe/0x640
? __might_fault+0x117/0x170
? reacquire_held_locks+0x4b0/0x4b0
? iommufd_selftest_destroy+0xd0/0xd0
? __might_fault+0xbe/0x170
iommufd_fops_ioctl+0x256/0x350
? iommufd_option+0x180/0x180
? __lock_acquire+0x1755/0x45f0
__x64_sys_ioctl+0xa13/0x1640
The bug is triggered when Syzkaller created multiple mock devices but
didn't destroy them in the same sequence, messing up the mock_dev_num
counter. Replace the atomic with an mock_dev_ida.
Cc: stable@vger.kernel.org
Fixes: 23a1b46f15d5 ("iommufd/selftest: Make the mock iommu driver into a real driver")
Link: https://lore.kernel.org/r/5af41d5af6d5c013cc51de01427abb8141b3587e.1708636627.git.nicolinc@nvidia.com
Reported-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/iommufd/selftest.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index 8abf9747773e..2bfe77bd351d 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -36,7 +36,7 @@ static struct mock_bus_type iommufd_mock_bus_type = { }, }; -static atomic_t mock_dev_num; +static DEFINE_IDA(mock_dev_ida); enum { MOCK_DIRTY_TRACK = 1, @@ -123,6 +123,7 @@ enum selftest_obj_type { struct mock_dev { struct device dev; unsigned long flags; + int id; }; struct selftest_obj { @@ -631,7 +632,7 @@ static void mock_dev_release(struct device *dev) { struct mock_dev *mdev = container_of(dev, struct mock_dev, dev); - atomic_dec(&mock_dev_num); + ida_free(&mock_dev_ida, mdev->id); kfree(mdev); } @@ -653,8 +654,12 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags) mdev->dev.release = mock_dev_release; mdev->dev.bus = &iommufd_mock_bus_type.bus; - rc = dev_set_name(&mdev->dev, "iommufd_mock%u", - atomic_inc_return(&mock_dev_num)); + rc = ida_alloc(&mock_dev_ida, GFP_KERNEL); + if (rc < 0) + goto err_put; + mdev->id = rc; + + rc = dev_set_name(&mdev->dev, "iommufd_mock%u", mdev->id); if (rc) goto err_put; |