kernel/linux.git/drivers/vfio/mdev, branch v6.6.132

vfio/mdev: Fix a null-ptr-deref bug for mdev_unregister_parent()

2023-09-22T18:48:04+00:00

Inject fault while probing mdpy.ko, if kstrdup() of create_dir() fails in kobject_add_internal() in kobject_init_and_add() in mdev_type_add() in parent_create_sysfs_files(), it will return 0 and probe successfully. And when rmmod mdpy.ko, the mdpy_dev_exit() will call mdev_unregister_parent(), the mdev_type_remove() may traverse uninitialized parent->types[i] in parent_remove_sysfs_files(), and it will cause below null-ptr-deref. If mdev_type_add() fails, return the error code and kset_unregister() to fix the issue. general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 2 PID: 10215 Comm: rmmod Tainted: G W N 6.6.0-rc2+ #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__kobject_del+0x62/0x1c0 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8 RSP: 0018:ffff88810695fd30 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffffffffa0270268 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000010 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10233a4ef1 R10: ffff888119d2778b R11: 0000000063666572 R12: 0000000000000000 R13: fffffbfff404e2d4 R14: dffffc0000000000 R15: ffffffffa0271660 FS: 00007fbc81981540(0000) GS:ffff888119d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc14a142dc0 CR3: 0000000110a62003 CR4: 0000000000770ee0 DR0: ffffffff8fb0bce8 DR1: ffffffff8fb0bce9 DR2: ffffffff8fb0bcea DR3: ffffffff8fb0bceb DR6: 00000000fffe0ff0 DR7: 0000000000000600 PKRU: 55555554 Call Trace: ? die_addr+0x3d/0xa0 ? exc_general_protection+0x144/0x220 ? asm_exc_general_protection+0x22/0x30 ? __kobject_del+0x62/0x1c0 kobject_del+0x32/0x50 parent_remove_sysfs_files+0xd6/0x170 [mdev] mdev_unregister_parent+0xfb/0x190 [mdev] ? mdev_register_parent+0x270/0x270 [mdev] ? find_module_all+0x9d/0xe0 mdpy_dev_exit+0x17/0x63 [mdpy] __do_sys_delete_module.constprop.0+0x2fa/0x4b0 ? module_flags+0x300/0x300 ? __fput+0x4e7/0xa00 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fbc813221b7 Code: 73 01 c3 48 8b 0d d1 8c 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 8c 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe780e0648 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 00007ffe780e06a8 RCX: 00007fbc813221b7 RDX: 000000000000000a RSI: 0000000000000800 RDI: 000055e214df9b58 RBP: 000055e214df9af0 R08: 00007ffe780df5c1 R09: 0000000000000000 R10: 00007fbc8139ecc0 R11: 0000000000000206 R12: 00007ffe780e0870 R13: 00007ffe780e0ed0 R14: 000055e214df9260 R15: 000055e214df9af0 Modules linked in: mdpy(-) mdev vfio_iommu_type1 vfio [last unloaded: mdpy] Dumping ftrace buffer: (ftrace buffer empty) ---[ end trace 0000000000000000 ]--- RIP: 0010:__kobject_del+0x62/0x1c0 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 51 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 28 48 8d 7d 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 01 00 00 48 8b 75 10 48 89 df 48 8d 6b 3c e8 RSP: 0018:ffff88810695fd30 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffffffffa0270268 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000010 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10233a4ef1 R10: ffff888119d2778b R11: 0000000063666572 R12: 0000000000000000 R13: fffffbfff404e2d4 R14: dffffc0000000000 R15: ffffffffa0271660 FS: 00007fbc81981540(0000) GS:ffff888119d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc14a142dc0 CR3: 0000000110a62003 CR4: 0000000000770ee0 DR0: ffffffff8fb0bce8 DR1: ffffffff8fb0bce9 DR2: ffffffff8fb0bcea DR3: ffffffff8fb0bceb DR6: 00000000fffe0ff0 DR7: 0000000000000600 PKRU: 55555554 Kernel panic - not syncing: Fatal exception Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 1 seconds.. Fixes: da44c340c4fe ("vfio/mdev: simplify mdev_type handling") Signed-off-by: Jinjie Ruan Reviewed-by: Eric Farman Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230918115551.1423193-1-ruanjinjie@huawei.com Signed-off-by: Alex Williamson

vfio/mdev: Move the compat_class initialization to module init

2023-06-27T18:05:26+00:00

The pointer to mdev_bus_compat_class is statically defined at the top of mdev_core, and was originally (commit 7b96953bc640 ("vfio: Mediated device Core driver") serialized by the parent_list_lock. The blamed commit removed this mutex, leaving the pointer initialization unserialized. As a result, the creation of multiple MDEVs in parallel (such as during boot) can encounter errors during the creation of the sysfs entries, such as: [ 8.337509] sysfs: cannot create duplicate filename '/class/mdev_bus' [ 8.337514] vfio_ccw 0.0.01d8: MDEV: Registered [ 8.337516] CPU: 13 PID: 946 Comm: driverctl Not tainted 6.4.0-rc7 #20 [ 8.337522] Hardware name: IBM 3906 M05 780 (LPAR) [ 8.337525] Call Trace: [ 8.337528] [<0000000162b0145a>] dump_stack_lvl+0x62/0x80 [ 8.337540] [<00000001622aeb30>] sysfs_warn_dup+0x78/0x88 [ 8.337549] [<00000001622aeca6>] sysfs_create_dir_ns+0xe6/0xf8 [ 8.337552] [<0000000162b04504>] kobject_add_internal+0xf4/0x340 [ 8.337557] [<0000000162b04d48>] kobject_add+0x78/0xd0 [ 8.337561] [<0000000162b04e0a>] kobject_create_and_add+0x6a/0xb8 [ 8.337565] [<00000001627a110e>] class_compat_register+0x5e/0x90 [ 8.337572] [<000003ff7fd815da>] mdev_register_parent+0x102/0x130 [mdev] [ 8.337581] [<000003ff7fdc7f2c>] vfio_ccw_sch_probe+0xe4/0x178 [vfio_ccw] [ 8.337588] [<0000000162a7833c>] css_probe+0x44/0x80 [ 8.337599] [<000000016279f4da>] really_probe+0xd2/0x460 [ 8.337603] [<000000016279fa08>] driver_probe_device+0x40/0xf0 [ 8.337606] [<000000016279fb78>] __device_attach_driver+0xc0/0x140 [ 8.337610] [<000000016279cbe0>] bus_for_each_drv+0x90/0xd8 [ 8.337618] [<00000001627a00b0>] __device_attach+0x110/0x190 [ 8.337621] [<000000016279c7c8>] bus_rescan_devices_helper+0x60/0xb0 [ 8.337626] [<000000016279cd48>] drivers_probe_store+0x48/0x80 [ 8.337632] [<00000001622ac9b0>] kernfs_fop_write_iter+0x138/0x1f0 [ 8.337635] [<00000001621e5e14>] vfs_write+0x1ac/0x2f8 [ 8.337645] [<00000001621e61d8>] ksys_write+0x70/0x100 [ 8.337650] [<0000000162b2bdc4>] __do_syscall+0x1d4/0x200 [ 8.337656] [<0000000162b3c828>] system_call+0x70/0x98 [ 8.337664] kobject: kobject_add_internal failed for mdev_bus with -EEXIST, don't try to register things with the same name in the same directory. [ 8.337668] kobject: kobject_create_and_add: kobject_add error: -17 [ 8.337674] vfio_ccw: probe of 0.0.01d9 failed with error -12 [ 8.342941] vfio_ccw_mdev aeb9ca91-10c6-42bc-a168-320023570aea: Adding to iommu group 2 Move the initialization of the mdev_bus_compat_class pointer to the init path, to match the cleanup in module exit. This way the code in mdev_register_parent() can simply link the new parent to it, rather than determining whether initialization is required first. Fixes: 89345d5177aa ("vfio/mdev: embedd struct mdev_parent in the parent data structure") Reported-by: Alexander Egorenkov Signed-off-by: Eric Farman Reviewed-by: Kevin Tian Reviewed-by: Christoph Hellwig Reviewed-by: Tony Krowiak Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230626133642.2939168-1-farman@linux.ibm.com Signed-off-by: Alex Williamson

vfio/mdev: Use sysfs_emit() to instead of sprintf()

2023-01-30T19:16:13+00:00

Follow the advice of the Documentation/filesystems/sysfs.rst and show() should only use sysfs_emit() or sysfs_emit_at() when formatting the value to be returned to user space. Signed-off-by: Bo Liu Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230129084117.2384-1-liubo03@inspur.com Signed-off-by: Alex Williamson

vfio-mdev: turn VFIO_MDEV into a selectable symbol

2023-01-23T18:26:29+00:00

VFIO_MDEV is just a library with helpers for the drivers. Stop making it a user choice and just select it by the drivers that use the helpers. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Tony Krowiak Link: https://lore.kernel.org/r/20230110091009.474427-3-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: add mdev available instance checking to the core

2022-10-04T18:06:58+00:00

Many of the mdev drivers use a simple counter for keeping track of the available instances. Move this code to the core code and store the counter in the mdev_parent. Implement it using correct locking, fixing mdpy. Drivers just provide the value in the mdev_driver at registration time and the core code takes care of maintaining it and exposing the value in sysfs. [hch: count instances per-parent instead of per-type, use an atomic_t to avoid taking mdev_list_lock in the show method] Signed-off-by: Jason Gunthorpe Signed-off-by: Christoph Hellwig Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-15-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: consolidate all the description sysfs into the core code

2022-10-04T18:06:58+00:00

Every driver just emits a string, simply add a method to the mdev_driver to return it and provide a standard sysfs show function. Remove the now unused types_attrs field in struct mdev_driver and the support code for it. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Link: https://lore.kernel.org/r/20220923092652.100656-14-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: consolidate all the available_instance sysfs into the core code

2022-10-04T18:06:58+00:00

Every driver just print a number, simply add a method to the mdev_driver to return it and provide a standard sysfs show function. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-13-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: consolidate all the name sysfs into the core code

2022-10-04T18:06:58+00:00

Every driver just emits a static string, simply add a field to the mdev_type for the driver to fill out or fall back to the sysfs name and provide a standard sysfs show function. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-12-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: consolidate all the device_api sysfs into the core code

2022-10-04T18:06:58+00:00

Every driver just emits a static string, simply feed it through the ops and provide a standard sysfs show function. Signed-off-by: Jason Gunthorpe Signed-off-by: Christoph Hellwig Reviewed-by: Tony Krowiak Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-11-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: remove mtype_get_parent_dev

2022-10-04T18:06:58+00:00

Just open code the dereferences in the only user. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Jason J. Herne Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-10-hch@lst.de Signed-off-by: Alex Williamson