In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix double release compute pasid
If kfd_process_device_init_vm returns failure after vm is converted to
compute vm and vm->pasid set to compute pasid, KFD will not take
pdd->drm_file reference. As a result, drm close file handler maybe
called to release the compute pasid before KFD process destroy worker to
release the same pasid and set vm->pasid to zero, this generates below
WARNING backtrace and NULL pointer access.
Add helper amdgpu_amdkfd_gpuvm_set_vm_pasid and call it at the last step
of kfd_process_device_init_vm, to ensure vm pasid is the original pasid
if acquiring vm failed or is the compute pasid with pdd->drm_file
reference taken to avoid double release same pasid.
amdgpu: Failed to create process VM object
ida_free called for id=32770 which is not allocated.
WARNING: CPU: 57 PID: 72542 at ../lib/idr.c:522 ida_free+0x96/0x140
RIP: 0010:ida_free+0x96/0x140
Call Trace:
amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
drm_file_free.part.13+0x216/0x270 [drm]
drm_close_helper.isra.14+0x60/0x70 [drm]
drm_release+0x6e/0xf0 [drm]
__fput+0xcc/0x280
____fput+0xe/0x20
task_work_run+0x96/0xc0
do_exit+0x3d0/0xc10
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:ida_free+0x76/0x140
Call Trace:
amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
drm_file_free.part.13+0x216/0x270 [drm]
drm_close_helper.isra.14+0x60/0x70 [drm]
drm_release+0x6e/0xf0 [drm]
__fput+0xcc/0x280
____fput+0xe/0x20
task_work_run+0x96/0xc0
do_exit+0x3d0/0xc10
In the Linux kernel, the following vulnerability has been resolved:
mtd: core: fix possible resource leak in init_mtd()
I got the error report while inject fault in init_mtd():
sysfs: cannot create duplicate filename '/devices/virtual/bdi/mtd-0'
Call Trace:
<TASK>
dump_stack_lvl+0x67/0x83
sysfs_warn_dup+0x60/0x70
sysfs_create_dir_ns+0x109/0x120
kobject_add_internal+0xce/0x2f0
kobject_add+0x98/0x110
device_add+0x179/0xc00
device_create_groups_vargs+0xf4/0x100
device_create+0x7b/0xb0
bdi_register_va.part.13+0x58/0x2d0
bdi_register+0x9b/0xb0
init_mtd+0x62/0x171 [mtd]
do_one_initcall+0x6c/0x3c0
do_init_module+0x58/0x222
load_module+0x268e/0x27d0
__do_sys_finit_module+0xd5/0x140
do_syscall_64+0x37/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
kobject_add_internal failed for mtd-0 with -EEXIST, don't try to register
things with the same name in the same directory.
Error registering mtd class or bdi: -17
If init_mtdchar() fails in init_mtd(), mtd_bdi will not be unregistered,
as a result, we can't load the mtd module again, to fix this by calling
bdi_unregister(mtd_bdi) after out_procfs label.
In the Linux kernel, the following vulnerability has been resolved:
kprobes: Fix check for probe enabled in kill_kprobe()
In kill_kprobe(), the check whether disarm_kprobe_ftrace() needs to be
called always fails. This is because before that we set the
KPROBE_FLAG_GONE flag for kprobe so that "!kprobe_disabled(p)" is always
false.
The disarm_kprobe_ftrace() call introduced by commit:
0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
to fix the NULL pointer reference problem. When the probe is enabled, if
we do not disarm it, this problem still exists.
Fix it by putting the probe enabled check before setting the
KPROBE_FLAG_GONE flag.
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix race on port output
assume the following setup on a single machine:
1. An openvswitch instance with one bridge and default flows
2. two network namespaces "server" and "client"
3. two ovs interfaces "server" and "client" on the bridge
4. for each ovs interface a veth pair with a matching name and 32 rx and
tx queues
5. move the ends of the veth pairs to the respective network namespaces
6. assign ip addresses to each of the veth ends in the namespaces (needs
to be the same subnet)
7. start some http server on the server network namespace
8. test if a client in the client namespace can reach the http server
when following the actions below the host has a chance of getting a cpu
stuck in a infinite loop:
1. send a large amount of parallel requests to the http server (around
3000 curls should work)
2. in parallel delete the network namespace (do not delete interfaces or
stop the server, just kill the namespace)
there is a low chance that this will cause the below kernel cpu stuck
message. If this does not happen just retry.
Below there is also the output of bpftrace for the functions mentioned
in the output.
The series of events happening here is:
1. the network namespace is deleted calling
`unregister_netdevice_many_notify` somewhere in the process
2. this sets first `NETREG_UNREGISTERING` on both ends of the veth and
then runs `synchronize_net`
3. it then calls `call_netdevice_notifiers` with `NETDEV_UNREGISTER`
4. this is then handled by `dp_device_event` which calls
`ovs_netdev_detach_dev` (if a vport is found, which is the case for
the veth interface attached to ovs)
5. this removes the rx_handlers of the device but does not prevent
packages to be sent to the device
6. `dp_device_event` then queues the vport deletion to work in
background as a ovs_lock is needed that we do not hold in the
unregistration path
7. `unregister_netdevice_many_notify` continues to call
`netdev_unregister_kobject` which sets `real_num_tx_queues` to 0
8. port deletion continues (but details are not relevant for this issue)
9. at some future point the background task deletes the vport
If after 7. but before 9. a packet is send to the ovs vport (which is
not deleted at this point in time) which forwards it to the
`dev_queue_xmit` flow even though the device is unregistering.
In `skb_tx_hash` (which is called in the `dev_queue_xmit`) path there is
a while loop (if the packet has a rx_queue recorded) that is infinite if
`dev->real_num_tx_queues` is zero.
To prevent this from happening we update `do_output` to handle devices
without carrier the same as if the device is not found (which would
be the code path after 9. is done).
Additionally we now produce a warning in `skb_tx_hash` if we will hit
the infinite loop.
bpftrace (first word is function name):
__dev_queue_xmit server: real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
netdev_core_pick_tx server: addr: 0xffff9f0a46d4a000 real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 2, reg_state: 1
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 6, reg_state: 2
ovs_netdev_detach_dev server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, reg_state: 2
netdev_rx_handler_unregister server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
netdev_rx_handler_unregister ret server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
dp_
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free of new block group that became unused
If a task creates a new block group and that block group becomes unused
before we finish its creation, at btrfs_create_pending_block_groups(),
then when btrfs_mark_bg_unused() is called against the block group, we
assume that the block group is currently in the list of block groups to
reclaim, and we move it out of the list of new block groups and into the
list of unused block groups. This has two consequences:
1) We move it out of the list of new block groups associated to the
current transaction. So the block group creation is not finished and
if we attempt to delete the bg because it's unused, we will not find
the block group item in the extent tree (or the new block group tree),
its device extent items in the device tree etc, resulting in the
deletion to fail due to the missing items;
2) We don't increment the reference count on the block group when we
move it to the list of unused block groups, because we assumed the
block group was on the list of block groups to reclaim, and in that
case it already has the correct reference count. However the block
group was on the list of new block groups, in which case no extra
reference was taken because it's local to the current task. This
later results in doing an extra reference count decrement when
removing the block group from the unused list, eventually leading the
reference count to 0.
This second case was caught when running generic/297 from fstests, which
produced the following assertion failure and stack trace:
[589.559] assertion failed: refcount_read(&block_group->refs) == 1, in fs/btrfs/block-group.c:4299
[589.559] ------------[ cut here ]------------
[589.559] kernel BUG at fs/btrfs/block-group.c:4299!
[589.560] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[589.560] CPU: 8 PID: 2819134 Comm: umount Tainted: G W 6.4.0-rc6-btrfs-next-134+ #1
[589.560] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[589.560] RIP: 0010:btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.561] Code: 68 62 da c0 (...)
[589.561] RSP: 0018:ffffa55a8c3b3d98 EFLAGS: 00010246
[589.561] RAX: 0000000000000058 RBX: ffff8f030d7f2000 RCX: 0000000000000000
[589.562] RDX: 0000000000000000 RSI: ffffffff953f0878 RDI: 00000000ffffffff
[589.562] RBP: ffff8f030d7f2088 R08: 0000000000000000 R09: ffffa55a8c3b3c50
[589.562] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8f05850b4c00
[589.562] R13: ffff8f030d7f2090 R14: ffff8f05850b4cd8 R15: dead000000000100
[589.563] FS: 00007f497fd2e840(0000) GS:ffff8f09dfc00000(0000) knlGS:0000000000000000
[589.563] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[589.563] CR2: 00007f497ff8ec10 CR3: 0000000271472006 CR4: 0000000000370ee0
[589.563] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[589.564] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[589.564] Call Trace:
[589.564] <TASK>
[589.565] ? __die_body+0x1b/0x60
[589.565] ? die+0x39/0x60
[589.565] ? do_trap+0xeb/0x110
[589.565] ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.566] ? do_error_trap+0x6a/0x90
[589.566] ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.566] ? exc_invalid_op+0x4e/0x70
[589.566] ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.567] ? asm_exc_invalid_op+0x16/0x20
[589.567] ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.567] ? btrfs_free_block_groups+0x449/0x4a0 [btrfs]
[589.567] close_ctree+0x35d/0x560 [btrfs]
[589.568] ? fsnotify_sb_delete+0x13e/0x1d0
[589.568] ? dispose_list+0x3a/0x50
[589.568] ? evict_inodes+0x151/0x1a0
[589.568] generic_shutdown_super+0x73/0x1a0
[589.569] kill_anon_super+0x14/0x30
[589.569] btrfs_kill_super+0x12/0x20 [btrfs]
[589.569] deactivate_locked
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
mm: fix zswap writeback race condition
The zswap writeback mechanism can cause a race condition resulting in
memory corruption, where a swapped out page gets swapped in with data that
was written to a different page.
The race unfolds like this:
1. a page with data A and swap offset X is stored in zswap
2. page A is removed off the LRU by zpool driver for writeback in
zswap-shrink work, data for A is mapped by zpool driver
3. user space program faults and invalidates page entry A, offset X is
considered free
4. kswapd stores page B at offset X in zswap (zswap could also be
full, if so, page B would then be IOed to X, then skip step 5.)
5. entry A is replaced by B in tree->rbroot, this doesn't affect the
local reference held by zswap-shrink work
6. zswap-shrink work writes back A at X, and frees zswap entry A
7. swapin of slot X brings A in memory instead of B
The fix:
Once the swap page cache has been allocated (case ZSWAP_SWAPCACHE_NEW),
zswap-shrink work just checks that the local zswap_entry reference is
still the same as the one in the tree. If it's not the same it means that
it's either been invalidated or replaced, in both cases the writeback is
aborted because the local entry contains stale data.
Reproducer:
I originally found this by running `stress` overnight to validate my work
on the zswap writeback mechanism, it manifested after hours on my test
machine. The key to make it happen is having zswap writebacks, so
whatever setup pumps /sys/kernel/debug/zswap/written_back_pages should do
the trick.
In order to reproduce this faster on a vm, I setup a system with ~100M of
available memory and a 500M swap file, then running `stress --vm 1
--vm-bytes 300000000 --vm-stride 4000` makes it happen in matter of tens
of minutes. One can speed things up even more by swinging
/sys/module/zswap/parameters/max_pool_percent up and down between, say, 20
and 1; this makes it reproduce in tens of seconds. It's crucial to set
`--vm-stride` to something other than 4096 otherwise `stress` won't
realize that memory has been corrupted because all pages would have the
same data.
In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid deadlock in fs reclaim with page writeback
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix calltrace warning in amddrm_buddy_fini
The following call trace is observed when removing the amdgpu driver, which
is caused by that BOs allocated for psp are not freed until removing.
[61811.450562] RIP: 0010:amddrm_buddy_fini.cold+0x29/0x47 [amddrm_buddy]
[61811.450577] Call Trace:
[61811.450577] <TASK>
[61811.450579] amdgpu_vram_mgr_fini+0x135/0x1c0 [amdgpu]
[61811.450728] amdgpu_ttm_fini+0x207/0x290 [amdgpu]
[61811.450870] amdgpu_bo_fini+0x27/0xa0 [amdgpu]
[61811.451012] gmc_v9_0_sw_fini+0x4a/0x60 [amdgpu]
[61811.451166] amdgpu_device_fini_sw+0x117/0x520 [amdgpu]
[61811.451306] amdgpu_driver_release_kms+0x16/0x30 [amdgpu]
[61811.451447] devm_drm_dev_init_release+0x4d/0x80 [drm]
[61811.451466] devm_action_release+0x15/0x20
[61811.451469] release_nodes+0x40/0xb0
[61811.451471] devres_release_all+0x9b/0xd0
[61811.451473] __device_release_driver+0x1bb/0x2a0
[61811.451476] driver_detach+0xf3/0x140
[61811.451479] bus_remove_driver+0x6c/0xf0
[61811.451481] driver_unregister+0x31/0x60
[61811.451483] pci_unregister_driver+0x40/0x90
[61811.451486] amdgpu_exit+0x15/0x447 [amdgpu]
For smu v13_0_2, if the GPU supports xgmi, refer to
commit f5c7e7797060 ("drm/amdgpu: Adjust removal control flow for smu v13_0_2"),
it will run gpu recover in AMDGPU_RESET_FOR_DEVICE_REMOVE mode when removing,
which makes all devices in hive list have hw reset but no resume except the
basic ip blocks, then other ip blocks will not call .hw_fini according to
ip_block.status.hw.
Since psp_free_shared_bufs just includes some software operations, so move
it to psp_sw_fini.
In the Linux kernel, the following vulnerability has been resolved:
drm/msm: Make .remove and .shutdown HW shutdown consistent
Drivers' .remove and .shutdown callbacks are executed on different code
paths. The former is called when a device is removed from the bus, while
the latter is called at system shutdown time to quiesce the device.
This means that some overlap exists between the two, because both have to
take care of properly shutting down the hardware. But currently the logic
used in these two callbacks isn't consistent in msm drivers, which could
lead to kernel panic.
For example, on .remove the component is deleted and its .unbind callback
leads to the hardware being shutdown but only if the DRM device has been
marked as registered.
That check doesn't exist in the .shutdown logic and this can lead to the
driver calling drm_atomic_helper_shutdown() for a DRM device that hasn't
been properly initialized.
A situation like this can happen if drivers for expected sub-devices fail
to probe, since the .bind callback will never be executed. If that is the
case, drm_atomic_helper_shutdown() will attempt to take mutexes that are
only initialized if drm_mode_config_init() is called during a device bind.
This bug was attempted to be fixed in commit 623f279c7781 ("drm/msm: fix
shutdown hook in case GPU components failed to bind"), but unfortunately
it still happens in some cases as the one mentioned above, i.e:
systemd-shutdown[1]: Powering off.
kvm: exiting hardware virtualization
platform wifi-firmware.0: Removing from iommu group 12
platform video-firmware.0: Removing from iommu group 10
------------[ cut here ]------------
WARNING: CPU: 6 PID: 1 at drivers/gpu/drm/drm_modeset_lock.c:317 drm_modeset_lock_all_ctx+0x3c4/0x3d0
...
Hardware name: Google CoachZ (rev3+) (DT)
pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_modeset_lock_all_ctx+0x3c4/0x3d0
lr : drm_modeset_lock_all_ctx+0x48/0x3d0
sp : ffff80000805bb80
x29: ffff80000805bb80 x28: ffff327c00128000 x27: 0000000000000000
x26: 0000000000000000 x25: 0000000000000001 x24: ffffc95d820ec030
x23: ffff327c00bbd090 x22: ffffc95d8215eca0 x21: ffff327c039c5800
x20: ffff327c039c5988 x19: ffff80000805bbe8 x18: 0000000000000034
x17: 000000040044ffff x16: ffffc95d80cac920 x15: 0000000000000000
x14: 0000000000000315 x13: 0000000000000315 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
x8 : ffff80000805bc28 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : ffff327c00128000 x1 : 0000000000000000 x0 : ffff327c039c59b0
Call trace:
drm_modeset_lock_all_ctx+0x3c4/0x3d0
drm_atomic_helper_shutdown+0x70/0x134
msm_drv_shutdown+0x30/0x40
platform_shutdown+0x28/0x40
device_shutdown+0x148/0x350
kernel_power_off+0x38/0x80
__do_sys_reboot+0x288/0x2c0
__arm64_sys_reboot+0x28/0x34
invoke_syscall+0x48/0x114
el0_svc_common.constprop.0+0x44/0xec
do_el0_svc+0x2c/0xc0
el0_svc+0x2c/0x84
el0t_64_sync_handler+0x11c/0x150
el0t_64_sync+0x18c/0x190
---[ end trace 0000000000000000 ]---
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000010eab1000
[0000000000000018] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
...
Hardware name: Google CoachZ (rev3+) (DT)
pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ww_mutex_lock+0x28/0x32c
lr : drm_modeset_lock_all_ctx+0x1b0/0x3d0
sp : ffff80000805bb50
x29: ffff80000805bb50 x28: ffff327c00128000 x27: 0000000000000000
x26: 00000
---truncated---