| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix UAF in smb2_reconnect_server()
The UAF bug is due to smb2_reconnect_server() accessing a session that
is already being teared down by another thread that is executing
__cifs_put_smb_ses(). This can happen when (a) the client has
connection to the server but no session or (b) another thread ends up
setting @ses->ses_status again to something different than
SES_EXITING.
To fix this, we need to make sure to unconditionally set
@ses->ses_status to SES_EXITING and prevent any other threads from
setting a new status while we're still tearing it down.
The following can be reproduced by adding some delay to right after
the ipc is freed in __cifs_put_smb_ses() - which will give
smb2_reconnect_server() worker a chance to run and then accessing
@ses->ipc:
kinit ...
mount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10
[disconnect srv]
ls /mnt/1 &>/dev/null
sleep 30
kdestroy
[reconnect srv]
sleep 10
umount /mnt/1
...
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
general protection fault, probably for non-canonical address
0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39
04/01/2014
Workqueue: cifsiod smb2_reconnect_server [cifs]
RIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0
Code: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad
de 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75
7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8
RSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83
RAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b
RDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800
RBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000
R13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000
FS: 0000000000000000(0000) GS:ffff888157c00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
<TASK>
? die_addr+0x36/0x90
? exc_general_protection+0x1c1/0x3f0
? asm_exc_general_protection+0x26/0x30
? __list_del_entry_valid_or_report+0x33/0xf0
__cifs_put_smb_ses+0x1ae/0x500 [cifs]
smb2_reconnect_server+0x4ed/0x710 [cifs]
process_one_work+0x205/0x6b0
worker_thread+0x191/0x360
? __pfx_worker_thread+0x10/0x10
kthread+0xe2/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: guarantee refcounted children from parent session
Avoid potential use-after-free bugs when walking DFS referrals,
mounting and performing DFS failover by ensuring that all children
from parent @tcon->ses are also refcounted. They're all needed across
the entire DFS mount. Get rid of @tcon->dfs_ses_list while we're at
it, too. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in smb2_is_valid_oplock_break()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in smb2_is_valid_lease_break()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in is_valid_oplock_break()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in smb2_is_network_name_deleted()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential UAF in cifs_signal_cifsd_for_reconnect()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
mlxsw: spectrum_acl_tcam: Fix possible use-after-free during rehash
The rehash delayed work migrates filters from one region to another
according to the number of available credits.
The migrated from region is destroyed at the end of the work if the
number of credits is non-negative as the assumption is that this is
indicative of migration being complete. This assumption is incorrect as
a non-negative number of credits can also be the result of a failed
migration.
The destruction of a region that still has filters referencing it can
result in a use-after-free [1].
Fix by not destroying the region if migration failed.
[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_acl_ctcam_region_entry_remove+0x21d/0x230
Read of size 8 at addr ffff8881735319e8 by task kworker/0:31/3858
CPU: 0 PID: 3858 Comm: kworker/0:31 Tainted: G W 6.9.0-rc2-custom-00782-gf2275c2157d8 #5
Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019
Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work
Call Trace:
<TASK>
dump_stack_lvl+0xc6/0x120
print_report+0xce/0x670
kasan_report+0xd7/0x110
mlxsw_sp_acl_ctcam_region_entry_remove+0x21d/0x230
mlxsw_sp_acl_ctcam_entry_del+0x2e/0x70
mlxsw_sp_acl_atcam_entry_del+0x81/0x210
mlxsw_sp_acl_tcam_vchunk_migrate_all+0x3cd/0xb50
mlxsw_sp_acl_tcam_vregion_rehash_work+0x157/0x1300
process_one_work+0x8eb/0x19b0
worker_thread+0x6c9/0xf70
kthread+0x2c9/0x3b0
ret_from_fork+0x4d/0x80
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 174:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
__kmalloc+0x19c/0x360
mlxsw_sp_acl_tcam_region_create+0xdf/0x9c0
mlxsw_sp_acl_tcam_vregion_rehash_work+0x954/0x1300
process_one_work+0x8eb/0x19b0
worker_thread+0x6c9/0xf70
kthread+0x2c9/0x3b0
ret_from_fork+0x4d/0x80
ret_from_fork_asm+0x1a/0x30
Freed by task 7:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
poison_slab_object+0x102/0x170
__kasan_slab_free+0x14/0x30
kfree+0xc1/0x290
mlxsw_sp_acl_tcam_region_destroy+0x272/0x310
mlxsw_sp_acl_tcam_vregion_rehash_work+0x731/0x1300
process_one_work+0x8eb/0x19b0
worker_thread+0x6c9/0xf70
kthread+0x2c9/0x3b0
ret_from_fork+0x4d/0x80
ret_from_fork_asm+0x1a/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Use device rbtree in iopf reporting path
The existing I/O page fault handler currently locates the PCI device by
calling pci_get_domain_bus_and_slot(). This function searches the list
of all PCI devices until the desired device is found. To improve lookup
efficiency, replace it with device_rbtree_find() to search the device
within the probed device rbtree.
The I/O page fault is initiated by the device, which does not have any
synchronization mechanism with the software to ensure that the device
stays in the probed device tree. Theoretically, a device could be released
by the IOMMU subsystem after device_rbtree_find() and before
iopf_get_dev_fault_param(), which would cause a use-after-free problem.
Add a mutex to synchronize the I/O page fault reporting path and the IOMMU
release device path. This lock doesn't introduce any performance overhead,
as the conflict between I/O page fault reporting and device releasing is
very rare. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach
This is the candidate patch of CVE-2023-47233 :
https://nvd.nist.gov/vuln/detail/CVE-2023-47233
In brcm80211 driver,it starts with the following invoking chain
to start init a timeout worker:
->brcmf_usb_probe
->brcmf_usb_probe_cb
->brcmf_attach
->brcmf_bus_started
->brcmf_cfg80211_attach
->wl_init_priv
->brcmf_init_escan
->INIT_WORK(&cfg->escan_timeout_work,
brcmf_cfg80211_escan_timeout_worker);
If we disconnect the USB by hotplug, it will call
brcmf_usb_disconnect to make cleanup. The invoking chain is :
brcmf_usb_disconnect
->brcmf_usb_disconnect_cb
->brcmf_detach
->brcmf_cfg80211_detach
->kfree(cfg);
While the timeout woker may still be running. This will cause
a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker.
Fix it by deleting the timer and canceling the worker in
brcmf_cfg80211_detach.
[arend.vanspriel@broadcom.com: keep timer delete as is and cancel work just before free] |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: rk3288 - Fix use after free in unprepare
The unprepare call must be carried out before the finalize call
as the latter can free the request. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: check/clear fast rx for non-4addr sta VLAN changes
When moving a station out of a VLAN and deleting the VLAN afterwards, the
fast_rx entry still holds a pointer to the VLAN's netdev, which can cause
use-after-free bugs. Fix this by immediately calling ieee80211_check_fast_rx
after the VLAN change. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Fix use-after-free bugs caused by sco_sock_timeout
When the sco connection is established and then, the sco socket
is releasing, timeout_work will be scheduled to judge whether
the sco disconnection is timeout. The sock will be deallocated
later, but it is dereferenced again in sco_sock_timeout. As a
result, the use-after-free bugs will happen. The root cause is
shown below:
Cleanup Thread | Worker Thread
sco_sock_release |
sco_sock_close |
__sco_sock_close |
sco_sock_set_timer |
schedule_delayed_work |
sco_sock_kill | (wait a time)
sock_put(sk) //FREE | sco_sock_timeout
| sock_hold(sk) //USE
The KASAN report triggered by POC is shown below:
[ 95.890016] ==================================================================
[ 95.890496] BUG: KASAN: slab-use-after-free in sco_sock_timeout+0x5e/0x1c0
[ 95.890755] Write of size 4 at addr ffff88800c388080 by task kworker/0:0/7
...
[ 95.890755] Workqueue: events sco_sock_timeout
[ 95.890755] Call Trace:
[ 95.890755] <TASK>
[ 95.890755] dump_stack_lvl+0x45/0x110
[ 95.890755] print_address_description+0x78/0x390
[ 95.890755] print_report+0x11b/0x250
[ 95.890755] ? __virt_addr_valid+0xbe/0xf0
[ 95.890755] ? sco_sock_timeout+0x5e/0x1c0
[ 95.890755] kasan_report+0x139/0x170
[ 95.890755] ? update_load_avg+0xe5/0x9f0
[ 95.890755] ? sco_sock_timeout+0x5e/0x1c0
[ 95.890755] kasan_check_range+0x2c3/0x2e0
[ 95.890755] sco_sock_timeout+0x5e/0x1c0
[ 95.890755] process_one_work+0x561/0xc50
[ 95.890755] worker_thread+0xab2/0x13c0
[ 95.890755] ? pr_cont_work+0x490/0x490
[ 95.890755] kthread+0x279/0x300
[ 95.890755] ? pr_cont_work+0x490/0x490
[ 95.890755] ? kthread_blkcg+0xa0/0xa0
[ 95.890755] ret_from_fork+0x34/0x60
[ 95.890755] ? kthread_blkcg+0xa0/0xa0
[ 95.890755] ret_from_fork_asm+0x11/0x20
[ 95.890755] </TASK>
[ 95.890755]
[ 95.890755] Allocated by task 506:
[ 95.890755] kasan_save_track+0x3f/0x70
[ 95.890755] __kasan_kmalloc+0x86/0x90
[ 95.890755] __kmalloc+0x17f/0x360
[ 95.890755] sk_prot_alloc+0xe1/0x1a0
[ 95.890755] sk_alloc+0x31/0x4e0
[ 95.890755] bt_sock_alloc+0x2b/0x2a0
[ 95.890755] sco_sock_create+0xad/0x320
[ 95.890755] bt_sock_create+0x145/0x320
[ 95.890755] __sock_create+0x2e1/0x650
[ 95.890755] __sys_socket+0xd0/0x280
[ 95.890755] __x64_sys_socket+0x75/0x80
[ 95.890755] do_syscall_64+0xc4/0x1b0
[ 95.890755] entry_SYSCALL_64_after_hwframe+0x67/0x6f
[ 95.890755]
[ 95.890755] Freed by task 506:
[ 95.890755] kasan_save_track+0x3f/0x70
[ 95.890755] kasan_save_free_info+0x40/0x50
[ 95.890755] poison_slab_object+0x118/0x180
[ 95.890755] __kasan_slab_free+0x12/0x30
[ 95.890755] kfree+0xb2/0x240
[ 95.890755] __sk_destruct+0x317/0x410
[ 95.890755] sco_sock_release+0x232/0x280
[ 95.890755] sock_close+0xb2/0x210
[ 95.890755] __fput+0x37f/0x770
[ 95.890755] task_work_run+0x1ae/0x210
[ 95.890755] get_signal+0xe17/0xf70
[ 95.890755] arch_do_signal_or_restart+0x3f/0x520
[ 95.890755] syscall_exit_to_user_mode+0x55/0x120
[ 95.890755] do_syscall_64+0xd1/0x1b0
[ 95.890755] entry_SYSCALL_64_after_hwframe+0x67/0x6f
[ 95.890755]
[ 95.890755] The buggy address belongs to the object at ffff88800c388000
[ 95.890755] which belongs to the cache kmalloc-1k of size 1024
[ 95.890755] The buggy address is located 128 bytes inside of
[ 95.890755] freed 1024-byte region [ffff88800c388000, ffff88800c388400)
[ 95.890755]
[ 95.890755] The buggy address belongs to the physical page:
[ 95.890755] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88800c38a800 pfn:0xc388
[ 95.890755] head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 95.890755] ano
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: use timestamp to check for set element timeout
Add a timestamp field at the beginning of the transaction, store it
in the nftables per-netns area.
Update set backend .insert, .deactivate and sync gc path to use the
timestamp, this avoids that an element expires while control plane
transaction is still unfinished.
.lookup and .update, which are used from packet path, still use the
current time to check if the element has expired. And .get path and dump
also since this runs lockless under rcu read size lock. Then, there is
async gc which also needs to check the current time since it runs
asynchronously from a workqueue. |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: Fix Use-After-Free in tcp_ao_connect_init
Since call_rcu, which is called in the hlist_for_each_entry_rcu traversal
of tcp_ao_connect_init, is not part of the RCU read critical section, it
is possible that the RCU grace period will pass during the traversal and
the key will be free.
To prevent this, it should be changed to hlist_for_each_entry_safe. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid use-after-free issue in f2fs_filemap_fault
syzbot reports a f2fs bug as below:
BUG: KASAN: slab-use-after-free in f2fs_filemap_fault+0xd1/0x2c0 fs/f2fs/file.c:49
Read of size 8 at addr ffff88807bb22680 by task syz-executor184/5058
CPU: 0 PID: 5058 Comm: syz-executor184 Not tainted 6.7.0-syzkaller-09928-g052d534373b7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x163/0x540 mm/kasan/report.c:488
kasan_report+0x142/0x170 mm/kasan/report.c:601
f2fs_filemap_fault+0xd1/0x2c0 fs/f2fs/file.c:49
__do_fault+0x131/0x450 mm/memory.c:4376
do_shared_fault mm/memory.c:4798 [inline]
do_fault mm/memory.c:4872 [inline]
do_pte_missing mm/memory.c:3745 [inline]
handle_pte_fault mm/memory.c:5144 [inline]
__handle_mm_fault+0x23b7/0x72b0 mm/memory.c:5285
handle_mm_fault+0x27e/0x770 mm/memory.c:5450
do_user_addr_fault arch/x86/mm/fault.c:1364 [inline]
handle_page_fault arch/x86/mm/fault.c:1507 [inline]
exc_page_fault+0x456/0x870 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
The root cause is: in f2fs_filemap_fault(), vmf->vma may be not alive after
filemap_fault(), so it may cause use-after-free issue when accessing
vmf->vma->vm_flags in trace_f2fs_filemap_fault(). So it needs to keep vm_flags
in separated temporary variable for tracepoint use. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: rtl8xxxu: add cancel_work_sync() for c2hcmd_work
The workqueue might still be running, when the driver is stopped. To
avoid a use-after-free, call cancel_work_sync() in rtl8xxxu_stop(). |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: qat - resolve race condition during AER recovery
During the PCI AER system's error recovery process, the kernel driver
may encounter a race condition with freeing the reset_data structure's
memory. If the device restart will take more than 10 seconds the function
scheduling that restart will exit due to a timeout, and the reset_data
structure will be freed. However, this data structure is used for
completion notification after the restart is completed, which leads
to a UAF bug.
This results in a KFENCE bug notice.
BUG: KFENCE: use-after-free read in adf_device_reset_worker+0x38/0xa0 [intel_qat]
Use-after-free read at 0x00000000bc56fddf (in kfence-#142):
adf_device_reset_worker+0x38/0xa0 [intel_qat]
process_one_work+0x173/0x340
To resolve this race condition, the memory associated to the container
of the work_struct is freed on the worker if the timeout expired,
otherwise on the function that schedules the worker.
The timeout detection can be done by checking if the caller is
still waiting for completion or not by using completion_done() function. |
| In the Linux kernel, the following vulnerability has been resolved:
mac802154: fix llsec key resources release in mac802154_llsec_key_del
mac802154_llsec_key_del() can free resources of a key directly without
following the RCU rules for waiting before the end of a grace period. This
may lead to use-after-free in case llsec_lookup_key() is traversing the
list of keys in parallel with a key deletion:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 4 PID: 16000 at lib/refcount.c:25 refcount_warn_saturate+0x162/0x2a0
Modules linked in:
CPU: 4 PID: 16000 Comm: wpan-ping Not tainted 6.7.0 #19
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x162/0x2a0
Call Trace:
<TASK>
llsec_lookup_key.isra.0+0x890/0x9e0
mac802154_llsec_encrypt+0x30c/0x9c0
ieee802154_subif_start_xmit+0x24/0x1e0
dev_hard_start_xmit+0x13e/0x690
sch_direct_xmit+0x2ae/0xbc0
__dev_queue_xmit+0x11dd/0x3c20
dgram_sendmsg+0x90b/0xd60
__sys_sendto+0x466/0x4c0
__x64_sys_sendto+0xe0/0x1c0
do_syscall_64+0x45/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
Also, ieee802154_llsec_key_entry structures are not freed by
mac802154_llsec_key_del():
unreferenced object 0xffff8880613b6980 (size 64):
comm "iwpan", pid 2176, jiffies 4294761134 (age 60.475s)
hex dump (first 32 bytes):
78 0d 8f 18 80 88 ff ff 22 01 00 00 00 00 ad de x.......".......
00 00 00 00 00 00 00 00 03 00 cd ab 00 00 00 00 ................
backtrace:
[<ffffffff81dcfa62>] __kmem_cache_alloc_node+0x1e2/0x2d0
[<ffffffff81c43865>] kmalloc_trace+0x25/0xc0
[<ffffffff88968b09>] mac802154_llsec_key_add+0xac9/0xcf0
[<ffffffff8896e41a>] ieee802154_add_llsec_key+0x5a/0x80
[<ffffffff8892adc6>] nl802154_add_llsec_key+0x426/0x5b0
[<ffffffff86ff293e>] genl_family_rcv_msg_doit+0x1fe/0x2f0
[<ffffffff86ff46d1>] genl_rcv_msg+0x531/0x7d0
[<ffffffff86fee7a9>] netlink_rcv_skb+0x169/0x440
[<ffffffff86ff1d88>] genl_rcv+0x28/0x40
[<ffffffff86fec15c>] netlink_unicast+0x53c/0x820
[<ffffffff86fecd8b>] netlink_sendmsg+0x93b/0xe60
[<ffffffff86b91b35>] ____sys_sendmsg+0xac5/0xca0
[<ffffffff86b9c3dd>] ___sys_sendmsg+0x11d/0x1c0
[<ffffffff86b9c65a>] __sys_sendmsg+0xfa/0x1d0
[<ffffffff88eadbf5>] do_syscall_64+0x45/0xf0
[<ffffffff890000ea>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
Handle the proper resource release in the RCU callback function
mac802154_llsec_key_del_rcu().
Note that if llsec_lookup_key() finds a key, it gets a refcount via
llsec_key_get() and locally copies key id from key_entry (which is a
list element). So it's safe to call llsec_key_put() and free the list
entry after the RCU grace period elapses.
Found by Linux Verification Center (linuxtesting.org). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/vma: Fix UAF on destroy against retire race
Object debugging tools were sporadically reporting illegal attempts to
free a still active i915 VMA object when parking a GT believed to be idle.
[161.359441] ODEBUG: free active (active state 0) object: ffff88811643b958 object type: i915_active hint: __i915_vma_active+0x0/0x50 [i915]
[161.360082] WARNING: CPU: 5 PID: 276 at lib/debugobjects.c:514 debug_print_object+0x80/0xb0
...
[161.360304] CPU: 5 PID: 276 Comm: kworker/5:2 Not tainted 6.5.0-rc1-CI_DRM_13375-g003f860e5577+ #1
[161.360314] Hardware name: Intel Corporation Rocket Lake Client Platform/RocketLake S UDIMM 6L RVP, BIOS RKLSFWI1.R00.3173.A03.2204210138 04/21/2022
[161.360322] Workqueue: i915-unordered __intel_wakeref_put_work [i915]
[161.360592] RIP: 0010:debug_print_object+0x80/0xb0
...
[161.361347] debug_object_free+0xeb/0x110
[161.361362] i915_active_fini+0x14/0x130 [i915]
[161.361866] release_references+0xfe/0x1f0 [i915]
[161.362543] i915_vma_parked+0x1db/0x380 [i915]
[161.363129] __gt_park+0x121/0x230 [i915]
[161.363515] ____intel_wakeref_put_last+0x1f/0x70 [i915]
That has been tracked down to be happening when another thread is
deactivating the VMA inside __active_retire() helper, after the VMA's
active counter has been already decremented to 0, but before deactivation
of the VMA's object is reported to the object debugging tool.
We could prevent from that race by serializing i915_active_fini() with
__active_retire() via ref->tree_lock, but that wouldn't stop the VMA from
being used, e.g. from __i915_vma_retire() called at the end of
__active_retire(), after that VMA has been already freed by a concurrent
i915_vma_destroy() on return from the i915_active_fini(). Then, we should
rather fix the issue at the VMA level, not in i915_active.
Since __i915_vma_parked() is called from __gt_park() on last put of the
GT's wakeref, the issue could be addressed by holding the GT wakeref long
enough for __active_retire() to complete before that wakeref is released
and the GT parked.
I believe the issue was introduced by commit d93939730347 ("drm/i915:
Remove the vma refcount") which moved a call to i915_active_fini() from
a dropped i915_vma_release(), called on last put of the removed VMA kref,
to i915_vma_parked() processing path called on last put of a GT wakeref.
However, its visibility to the object debugging tool was suppressed by a
bug in i915_active that was fixed two weeks later with commit e92eb246feb9
("drm/i915/active: Fix missing debug object activation").
A VMA associated with a request doesn't acquire a GT wakeref by itself.
Instead, it depends on a wakeref held directly by the request's active
intel_context for a GT associated with its VM, and indirectly on that
intel_context's engine wakeref if the engine belongs to the same GT as the
VMA's VM. Those wakerefs are released asynchronously to VMA deactivation.
Fix the issue by getting a wakeref for the VMA's GT when activating it,
and putting that wakeref only after the VMA is deactivated. However,
exclude global GTT from that processing path, otherwise the GPU never goes
idle. Since __i915_vma_retire() may be called from atomic contexts, use
async variant of wakeref put. Also, to avoid circular locking dependency,
take care of acquiring the wakeref before VM mutex when both are needed.
v7: Add inline comments with justifications for:
- using untracked variants of intel_gt_pm_get/put() (Nirmoy),
- using async variant of _put(),
- not getting the wakeref in case of a global GTT,
- always getting the first wakeref outside vm->mutex.
v6: Since __i915_vma_active/retire() callbacks are not serialized, storing
a wakeref tracking handle inside struct i915_vma is not safe, and
there is no other good place for that. Use untracked variants of
intel_gt_pm_get/put_async().
v5: Replace "tile" with "GT" across commit description (Rodrigo),
-
---truncated--- |
