| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: vub300: defer reset until cmd_mutex is unlocked
vub300_cmndwork_thread() holds cmd_mutex while it sends a command and
waits for the command response. If the response wait times out,
__vub300_command_response() kills the command URBs and then synchronously
resets the USB device through usb_reset_device().
That reset path re-enters the driver through vub300_pre_reset(), which
also takes cmd_mutex. The worker therefore tries to acquire the same
mutex recursively while it is still holding it from the command path.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the real worker and timeout/reset carrier:
vub300_cmndwork_thread()
__vub300_command_response()
usb_lock_device_for_reset()
usb_reset_device()
vub300_pre_reset()
Lockdep reported the same-task recursive acquisition on cmd_mutex:
WARNING: possible recursive locking detected
... (&test_vub300.cmd_mutex) ... at: usb_reset_device... [vuln_msv]
... (&test_vub300.cmd_mutex) ... at: vub300_cmndwork_thread+0x12/0x20 [vuln_msv]
Workqueue: vub300_cmd_wq vub300_cmndwork_thread [vuln_msv]
*** DEADLOCK ***
Return a flag from __vub300_command_response() when the timeout path needs
a device reset, then perform the reset after vub300_cmndwork_thread() has
cleared the in-flight command state and dropped cmd_mutex. The reset is
still attempted before mmc_request_done(), preserving the existing request
completion ordering while avoiding the recursive lock. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (occ) unregister sysfs devices outside occ lock
occ_active(false) and occ_shutdown() unregister sysfs-backed devices while
occ->lock is held. hwmon_device_unregister() and sysfs_remove_group() can
wait for active sysfs callbacks to drain, and those callbacks can enter the
OCC update path and try to take occ->lock again. That gives the unregister
paths the lock ordering occ->lock -> sysfs callback drain, while a callback
has the opposite edge sysfs callback -> occ->lock.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the real unregister and callback carrier:
occ_shutdown()
hwmon_device_unregister()
occ_show_temp_1()
occ_update_response()
Lockdep reported the circular dependency with occ_shutdown() already
holding the OCC mutex and hwmon_device_unregister() waiting on the sysfs
side:
WARNING: possible circular locking dependency detected
... (sysfs_lock) ... at: hwmon_device_unregister+0x12/0x30 [vuln_msv]
... (&test_occ.lock) ... at: occ_shutdown.constprop.0+0xe/0x40 [vuln_msv]
occ_update_response.isra.0+0xb/0x20 [vuln_msv]
occ_show_temp_1.constprop.0.isra.0+0x23/0x40 [vuln_msv]
*** DEADLOCK ***
Serialize hwmon registration and removal with a separate hwmon_lock.
Under that lock, detach occ->hwmon and update occ->active while occ->lock
is held so concurrent OCC state changes still see a stable state, then
drop occ->lock before calling hwmon_device_unregister(). Remove the
driver sysfs group before taking occ->lock in occ_shutdown(), so draining
the driver attributes cannot wait while the OCC mutex is held. Also make
OCC update callbacks return -ENODEV after deactivation, so callbacks that
already passed sysfs active protection do not poll the hardware after
teardown has detached the hwmon device. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: sco: Fix a race condition in sco_sock_timeout()
sco_sock_timeout() runs asynchronously and lock_sock(sk). If the socket
is closing while the timer is running, it holds the same lock
(lock_sock(sk)) twice, leading to a deadlock.
CPU 0 CPU 1
==================== ======================
sco_sock_close()
sco_sock_timeout()
lock_sock(sk) // <-- LOCK
__sco_sock_close()
sco_chan_del()
sco_conn_put()
sco_conn_free()
disable_delayed_work_sync()
lock(sk) // <-- SAME LOCK
Fix this by moving disable_delayed_work_sync() outside of lock_sock(sk),
ensuring that no lock_sock(sk) is held before sco_sock_timeout().
Lockdep splat:
WARNING: possible circular locking dependency detected
6.13.0-rc4 #7 Not tainted
syz-executor292/9514 is trying to acquire lock:
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire sect/v6.13-rc4/./include/linux/rcupdate.h:337 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_read_lock sect/v6.13-rc4/./include/linux/rcupdate.h:849 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4137 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xd1/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195
but task is already holding lock:
ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_close+0x25/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:524
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849
lock_sock_nested+0x48/0x130 sect/v6.13-rc4/net/core/sock.c:3622
lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
sco_sock_timeout+0xbe/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:158
process_one_work sect/v6.13-rc4/kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa99/0x18f0 sect/v6.13-rc4/kernel/workqueue.c:3310
worker_thread+0x8a9/0xd80 sect/v6.13-rc4/kernel/workqueue.c:3391
kthread+0x2c6/0x360 sect/v6.13-rc4/kernel/kthread.c:389
ret_from_fork+0x4e/0x80 sect/v6.13-rc4/arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 sect/v6.13-rc4/arch/x86/entry/entry_64.S:244
-> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}:
check_prev_add sect/v6.13-rc4/kernel/locking/lockdep.c:3161 [inline]
check_prevs_add sect/v6.13-rc4/kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x1888/0x5760 sect/v6.13-rc4/kernel/locking/lockdep.c:3904
__lock_acquire+0x13b4/0x2120 sect/v6.13-rc4/kernel/locking/lockdep.c:5226
lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849
touch_work_lockdep_map sect/v6.13-rc4/kernel/workqueue.c:3909 [inline]
start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4163 [inline]
__flush_work+0x70f/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195
__cancel_work_sync sect/v6.13-rc4/kernel/workqueue.c:4351 [inline]
disable_delayed_work_sync+0xbb/0xf0 sect/v6.13-rc4/kernel/workqueue.c:4514
sco_conn_free sect/v6.13-rc4/net/bluetooth/sco.c:95 [inline]
kref_put sect/v6.13-rc4/./include/linux/kref.h:65 [inline]
sco_conn_put+0x18f/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:107
sco_chan_del+0xe2/0x210 sect/v6.13-rc4/net/bluetooth/sco.c:236
sco_sock_close+0x8f/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:526
sco_sock_release+0x62/0x2d0 sect/v6.13-rc4/net/blueto
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
iomap: add a separate bio_set for iomap_split_ioend
iomap_split_ioend can split bios that already come from
iomap_ioend_bioset and thus deadlock when the bioset is exhausted.
Add a separate bio_set to avoid this deadlock.
Christian Brauner <brauner@kernel.org> says:
Mark iomap_ioend_split_bioset static as it is only used in ioend.c,
fixing the sparse warning reported by the kernel test robot. |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: LAG, MPESW, Fix missing complete() on devcom error
mlx5_mpesw_work() returned without calling complete() when
mlx5_lag_get_devcom_comp() returned NULL. A caller that queued the
work and waited on mpesww->comp would block indefinitely.
Funnel the early-return path through a new "complete" label so the
waiter is always woken. |
| In the Linux kernel, the following vulnerability has been resolved:
s390/vfio_ccw: Move cp cleanup out of not operational
The fsm_notoper() routine is called when the device has been
lost, and is (by definition) no longer operational. Since this
can happen asynchronously from the normal behavior of the
driver, the cleanup may happen when holding other locks
in the calling sequence (notably, the cio subchannel lock).
Push the cleanup of the private->cp resources to a workqueue,
where it can be done out from under that lock sequence and
a future patch can safely manage the locking requirements. |
| In the Linux kernel, the following vulnerability has been resolved:
eth: bnxt: avoid deadlock when canceling IRQ affinity notifier
Unregistering IRQ affinity notifiers waits for the callback synchronously.
bnxt takes the netdev instance lock in the notifier (to restart the queue)
and cancels the work under the same lock. This may obviously deadlock.
Move the restart to the async service task. The queue restart isn't
super time sensitive. Store the new TPH tag, schedule the task.
Safely canceling the service task is already ironed out.
In bnxt_request_irq() the order of registering notifier, affinity and
initial TPH programming has to be inverted. I think it was racy
previously since user may trigger an update as soon as notifier
is installed.
There's a small known gap - if pcie_tph_get_cpu_st() fails at init
and the target tag is 0 we may miss programming the entry.
This does not seem worth fixing, the code has skip-on-failure
all over the place, anyway. |
| In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Take cgroup_lock() first in scx_cgroup_lock()
scx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes
cgroup_lock(), which can deadlock through kernfs:
scx enable/disable cgroup rmdir cpu.weight write
------------------ ------------ ----------------
cgroup_lock()
percpu_down_write(rwsem)
cgroup_lock()
kernfs_get_active()
percpu_down_read(rwsem)
kernfs_drain()
The enable path waits for the rmdir to release cgroup_mutex. The rmdir,
deactivating the cpu controller's files, waits in kernfs_drain() for the
write's active reference. The write, in scx_group_set_weight(), waits for
the rwsem behind the pending writer.
Take cgroup_lock() first. The set_* paths take no cgroup locks inside the
read side, so a pending write-lock then only waits for read sections that
always run to completion, and no dependency from the rwsem back to
cgroup_mutex remains. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack: defer invalid log until after unlock
TCP and SCTP conntrack paths can emit invalid-packet logs while ct->lock
is still held.
When invalid logging is routed to nfnetlink_log and conntrack export is
enabled, the log path can re-enter conntrack netlink glue and dump the
same conntrack again. Protocol attribute dumping may take ct->lock, so
logging while holding that lock can deadlock.
Defer the TCP invalid logs by storing only the minimal log context while
ct->lock is held and emitting the log after unlocking. Also make the TCP
timeout-lowering invalid path return whether a log is needed, then emit
that log after unlocking.
Do the same for the SCTP invalid state-transition log that can be reached
while ct->lock is held.
Add a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers
that log invalid conntracks while holding ct->lock are caught outside TCP
and SCTP as well. |
| In the Linux kernel, the following vulnerability has been resolved:
super: fix emergency thaw deadlock on frozen block devices
do_thaw_all_callback() calls bdev_thaw() while holding sb->s_umount
exclusively. If the block device was frozen via bdev_freeze() dropping
the last block layer freeze reference calls fs_bdev_thaw() which
reacquires s_umount:
do_thaw_all_callback(sb)
super_lock_excl(sb) # holds sb->s_umount
bdev_thaw(sb->s_bdev)
mutex_lock(&bdev->bd_fsfreeze_mutex)
# bd_fsfreeze_count drops 1 -> 0
bd_holder_ops->thaw == fs_bdev_thaw
get_bdev_super(bdev)
bdev_super_lock(bdev, true)
super_lock(sb, true)
down_write(&sb->s_umount) # same task: deadlock
The emergency thaw worker deadlocks against itself holding both
s_umount and bd_fsfreeze_mutex. That fscks any subsequent unmount,
freeze, or thaw of that filesystem and block device.
[ 81.878470] sysrq: Show Blocked State
[ 81.880140] task:kworker/0:1 state:D stack:0 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000
[ 81.884876] Workqueue: events do_thaw_all
[ 81.886656] Call Trace:
[ 81.887759] <TASK>
[ 81.888763] __schedule+0x579/0x1420
[ 81.890372] schedule+0x3a/0x100
[ 81.891794] schedule_preempt_disabled+0x15/0x30
[ 81.893848] rwsem_down_write_slowpath+0x1ea/0x900
[ 81.895191] ? __pfx_do_thaw_all_callback+0x10/0x10
[ 81.896528] down_write+0xbd/0xc0
[ 81.897505] super_lock+0x91/0x180
[ 81.898457] ? __mutex_lock+0xa99/0x1140
[ 81.900748] ? __mutex_unlock_slowpath+0x1f/0x400
[ 81.902069] bdev_super_lock+0x5b/0x150
[ 81.903132] get_bdev_super+0x10/0x60
[ 81.904042] fs_bdev_thaw+0x23/0xf0
[ 81.904755] bdev_thaw+0x82/0x100
[ 81.905484] do_thaw_all_callback+0x2c/0x50
[ 81.906298] __iterate_supers+0x5d/0x130
[ 81.907067] do_thaw_all+0x20/0x40
[ 81.907739] process_one_work+0x206/0x5e0
[ 81.908545] worker_thread+0x1e2/0x3c0
[ 81.909339] ? __pfx_worker_thread+0x10/0x10
[ 81.910171] kthread+0xf4/0x130
[ 81.910799] ? __pfx_kthread+0x10/0x10
[ 81.911528] ret_from_fork+0x2e2/0x3b0
[ 81.912259] ? __pfx_kthread+0x10/0x10
[ 81.913010] ret_from_fork_asm+0x1a/0x30
[ 81.913806] </TASK>
bdev_super_lock() even documents the violated requirement with
lockdep_assert_not_held(&sb->s_umount).
Acquiring bd_fsfreeze_mutex under s_umount also inverts the
bd_fsfreeze_mutex vs. s_umount ordering established by
bdev_{freeze,thaw}() and can thus ABBA against a concurrent block-layer
freeze even when the recursive path isn't hit.
Fix this by not holding s_umount around the bdev_thaw() loop at all. Pin
the superblock with an active reference instead as
filesystems_freeze_callback() does. The active reference keeps the
superblock from being shut down and so ->s_bdev stays valid without
holding s_umount. The block-layer-held freeze is dropped by
fs_bdev_thaw() with FREEZE_MAY_NEST | FREEZE_HOLDER_USERSPACE exactly as
a regular unfreeze would and thaw_super_locked() handles
filesystem-level freezes as before.
The emergency thaw path has deadlocked like this in one form or
another for a long long time but the current exclusively-held
shape dates back to commit [1] where thaw_bdev() already ended in
thaw_super() with s_umount held by do_thaw_all_callback(). |
| In the Linux kernel, the following vulnerability has been resolved:
audit: fix recursive locking deadlock in audit_dupe_exe()
A deadlock occurs in the audit subsystem when duplicating
executable-related rules.
When a file is moved (e.g., via do_renameat2()), the VFS layer locks
the parent directory (I_MUTEX_PARENT), which synchronously triggers an
fsnotify_move event. If an existing executable audit rule matches the
file being moved, the audit subsystem catches this event and calls
audit_dupe_exe() to duplicate the watch and update the rule. Then,
audit_alloc_mark() would call kern_path_parent() to resolve the path,
leading to a blind attempt to acquire the exact same I_MUTEX_PARENT lock
already held by the task, resulting in the following recursive locking
deadlock:
============================================
WARNING: possible recursive locking detected
6.12.0-55.27.1.el10_0.x86_64+debug #1 Not tainted
--------------------------------------------
mv/5099 is trying to acquire lock:
ffff888132845358 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{3:3},
at: __kern_path_locked+0x10a/0x2f0
but task is already holding lock:
ffff888132846b58 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{3:3},
at: lock_two_directories+0x13f/0x2b0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&inode->i_sb->s_type->i_mutex_dir_key/1);
lock(&inode->i_sb->s_type->i_mutex_dir_key/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
6 locks held by mv/5099:
#0: ffff888112a9c440 (sb_writers#13)
at: do_renameat2+0x34c/0xbc0
#1: ffff888112a9c790 (&type->s_vfs_rename_key#3)
at: do_renameat2+0x415/0xbc0
#2: ffff888132846b58 (&inode->i_sb->s_type->i_mutex_dir_key/1)
at: lock_two_directories+0x13f/0x2b0
#3: ffff888132845358 (&inode->i_sb->s_type->i_mutex_dir_key/5)
at: lock_two_directories+0x175/0x2b0
#4: ffffffffb3a1fb10 (&fsnotify_mark_srcu)
at: fsnotify+0x454/0x28a0
#5: ffffffffaf886230 (audit_filter_mutex)
at: audit_update_watch+0x36/0x11e0
stack backtrace:
Call Trace:
<TASK>
dump_stack_lvl+0x6f/0xb0
print_deadlock_bug.cold+0xbd/0xca
validate_chain+0x83a/0xf00
__lock_acquire+0xcac/0x1d20
lock_acquire.part.0+0x11b/0x360
down_write_nested+0x9f/0x230
__kern_path_locked+0x10a/0x2f0
kern_path_locked+0x26/0x40
audit_alloc_mark+0xfb/0x4f0
audit_dupe_exe+0x6c/0xe0
audit_dupe_rule+0x6c2/0xc00
audit_update_watch+0x4cc/0x11e0
audit_watch_handle_event+0x12c/0x1b0
send_to_group+0x5d0/0x8b0
fsnotify+0x615/0x28a0
fsnotify_move+0x1d8/0x630
vfs_rename+0xdcd/0x1df0
do_renameat2+0x9d4/0xbc0
__x64_sys_renameat+0x192/0x260
do_syscall_64+0x92/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f0491fe8c4e
Code: 0f 1f 40 00 48 8b 15 c1 e1 16 00 f7 d8 64 89 02 b8 ff ff ff ff
c3 66 0f 1f 44 00 00 f3 0f 1e fa 49 89 ca b8 08 01 00 00 0f 05 <48>
3d 00 f0 ff ff 77 0a c3 66 0f 1f 84 00 00 00 00 00 48 8b 15 89
RSP: 002b:00007ffc7210bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000108
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0491fe8c4e
RDX: 0000000000000003 RSI: 00007ffc7210e6c8 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 00005575eb2dae2a R11: 0000000000000246 R12: 00005575eb2dae2a
R13: 00007ffc7210e6c8 R14: 0000000000000003 R15: 00000000ffffff9c
</TASK>
The aforementioned deadlock can be consistently reproduced by running
the script below:
audit-dupe-exe-deadlock.sh
--------------------------
#!/bin/bash
auditctl -D
mkdir -p /tmp/foo
touch /tmp/file
auditctl -a always,exit -F exe=/tmp/file -F path=/tmp/file -S all -k dr
mv /tmp/file /tmp/foo/file
rm -Rf /tmp/foo
This patch fixes the issue by introducing struct audit_watch_ctx to pass
the fsnotify event context down to audit_alloc_mark(). By utilizing the
already-resolved directory inode provided by the event, we bypass the
kern_path_parent() path resol
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
md/raid5: avoid R5_Overlap races while breaking stripe batches
KCSAN report a race in break_stripe_batch_list() vs. raid5_make_request()
on sh->dev[i].flags (plain word write vs. atomic bit op)..
and .. one possible scenario is:
CPU1 CPU2
break_stripe_batch_list(sh1)
-> handle sh2
-> lock(sh2)
-> sh2->batch_head = NULL
-> unlock(sh2)
-> test_and_clear_bit(R5_Overlap, sh2->dev[i].flags)
-> wake_up_bit(sh2->dev[i].flags)
raid5_make_request()
-> add_all_stripe_bios(sh2)
-> lock(sh2)
-> stripe_bio_overlaps(sh2) returns true
batch_head is NULL, so new bio overlap
exist bio on sh2 -> true
-> set_bit(R5_Overlap, sh2->dev[i].flags)
-> unlock(sh2)
-> wait_on_bit(sh2->dev[i].flags)
-> sh2->dev[i].flags = sh1->dev[i].flags & ~R5_Overlap
No wait_up_bit(), CPU2 could be wait_on_bit() forever...
Fix by :
- Expand the protect zone.
- Use batch_head's device flag's snaphot when no held head_sh->stripe_lock.
- Move sh/head_sh->batch_head = NULL to the end of protected zone , and ,
any concurrent add_all_stripe_bios() grabs sh->stripe_lock now either:
- see batch_head != null, and , is rejected by stripe_bio_overlaps()
under the lock (no R5_Overlap wait ) , or ,
- sees batch_head == NULL, only after dev[i].flags has already been
set and the prior R5_Overlap waiters worken.
KCSAN report:
================================================
BUG: KCSAN: data-race in break_stripe_batch_list / raid5_make_request
write (marked) to 0xffff8e89c8117548 of 8 bytes by task 4042 on cpu 0:
raid5_make_request+0xea0/0x2930
md_handle_request+0x4a2/0xa40
md_submit_bio+0x109/0x1a0
__submit_bio+0x2ec/0x390
submit_bio_noacct_nocheck+0x457/0x710
submit_bio_noacct+0x2a7/0xc20
submit_bio+0x56/0x250
blkdev_direct_IO+0x54c/0xda0
blkdev_write_iter+0x38f/0x570
aio_write+0x22b/0x490
io_submit_one+0xa51/0xf70
__x64_sys_io_submit+0xf7/0x220
x64_sys_call+0x1907/0x1c60
do_syscall_64+0x130/0x570
entry_SYSCALL_64_after_hwframe+0x76/0x7e
read to 0xffff8e89c8117548 of 8 bytes by task 4010 on cpu 5:
break_stripe_batch_list+0x249/0x480
handle_stripe_clean_event+0x720/0x9b0
handle_stripe+0x32fb/0x4500
handle_active_stripes.isra.0+0x6e0/0xa50
raid5d+0x7e0/0xba0
md_thread+0x15a/0x2d0
kthread+0x1e3/0x220
ret_from_fork+0x37a/0x410
ret_from_fork_asm+0x1a/0x30
value changed: 0x0000000000000019 -> 0x0000000000000099 --> R5_Overlap |
| In the Linux kernel, the following vulnerability has been resolved:
i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock
Fix a severe AB/BA deadlock between the Common Clock Framework (CCF)
and the I2C adapter lock, which triggers when an I2C-controlled clock
generator client (like the Si5351) is registered or modified under the CCF.
During an i2c client clock (generator) frequency change, the CCF acquires its global
'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's
chip registers, stalling for the adapter's I2C bus lock.
Concurrently, an independent, parallel transfer on the same bus (e.g., a GPIO
expander handling LEDs) can hold the I2C adapter lock. Inside this parallel
transfer path, jz4780_i2c_set_speed() calls clk_get_rate() on the host
controller's input clock to calculate bus timings. This call attempts to acquire
the blocked CCF 'prepare_lock', creating a circular dependency that freezes
the system.
The jz4780 host controller clock itself is static and never changes at runtime.
However, calling clk_get_rate() inside the active transfer path introduces
an unnecessary dependency on the CCF internal locks.
Eliminate this synchronous clk_get_rate() call from the active transfer
path by caching the static host peripheral clock rate once - inside the private
jz4780_i2c structure during jz4780_i2c_probe(). Update jz4780_i2c_set_speed()
to use this cached value, safely decoupling active I2C transactions from the
CCF internal locks without any risk of stale timings.
Assisted-by web based Google AI (pinpointing the bug and writing the message). |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT
Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not
belong to the same superblock as the original file. Currently, this
validation is performed inside ext4_move_extents() by
mext_check_validity(), but only after lock_two_nondirectories() has
already acquired the inode locks. When the donor fd refers to a file
on a different filesystem (e.g., overlayfs), this late validation
creates a circular lock dependency:
CPU0 (overlayfs write) CPU1 (ext4 ioctl)
---- ----
inode_lock(ovl_inode)
mnt_want_write_file(filp)
sb_start_write(ext4_sb) [sb_writers]
backing_file_write_iter()
vfs_iter_write(real_file)
file_start_write(real_file)
sb_start_write(ext4_sb) [blocked by freeze]
lock_two_nondirectories()
inode_lock(ovl_inode) [blocked]
With a concurrent freeze operation holding sb_writers write side, this
forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits
for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock.
Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files,
it fundamentally requires both files to reside on the same ext4
filesystem. Moving the superblock check before any lock acquisition
is both semantically correct and eliminates the circular dependency
by ensuring that cross-filesystem donor fds are rejected before
sb_writers or inode locks are taken. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: fix deadlock waiting for ticket during data relocation
When performing data relocation on a zoned filesystem, BTRFS can deadlock
in handle_reserve_tickets(). The relocation process is waiting on a space
reservation ticket that can never be fulfilled, because the relocation
itself is the operation responsible for freeing up that space.
Fix this by introducing a new flush state,
BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, specifically for data chunk
allocation during zoned relocation. Like
BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE, this state uses
priority_reclaim_data_space() instead of the normal flushing path, which
avoids re-entering the relocation code and breaking the deadlock cycle.
In btrfs_alloc_data_chunk_ondemand(), select this new flush state when the
inode belongs to a data relocation root on a zoned filesystem. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock cloning inline extent when using flushoncommit
In commit b48c980b6a7e ("btrfs: fix deadlock between reflink and
transaction commit when using flushoncommit") a deadlock was fixed
between reflinks and transaction commits when the fs is mounted with the
flushoncommit option. This happened when we had to copy an inline extent's
data to the destination file. However the issue was fixed only for the
case where the destination offset is 0, it missed the case when the offset
is greater than zero.
Fix this by ensuring we get i_size update whenever we copied an inline
extent's data into the destination file.
Syzbot reported this with the following trace:
INFO: task kworker/u8:3:57 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3 state:D stack:21600 pid:57 tgid:57 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: writeback wb_workfn (flush-btrfs-129)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7298
wait_extent_bit fs/btrfs/extent-io-tree.c:905 [inline]
btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:2008
btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]
btrfs_invalidate_folio+0x440/0xc00 fs/btrfs/inode.c:7718
extent_writepage fs/btrfs/extent_io.c:1848 [inline]
extent_write_cache_pages fs/btrfs/extent_io.c:2552 [inline]
btrfs_writepages+0x12f3/0x2410 fs/btrfs/extent_io.c:2684
do_writepages+0x32e/0x550 mm/page-writeback.c:2571
__writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
wb_writeback+0x445/0xb00 fs/fs-writeback.c:2241
wb_do_writeback fs/fs-writeback.c:2388 [inline]
wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428
process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
process_scheduled_works kernel/workqueue.c:3401 [inline]
worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz.0.145:8523 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.145 state:D stack:22752 pid:8523 tgid:8522 ppid:5850 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7298
wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
__writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2847
try_to_writeback_inodes_sb+0x9a/0xc0 fs/fs-writeback.c:2895
btrfs_start_delalloc_flush fs/btrfs/transaction.c:2182 [inline]
btrfs_commit_transaction+0x813/0x2fc0 fs/btrfs/transaction.c:2371
btrfs_sync_file+0xdf4/0x1230 fs/btrfs/file.c:1822
generic_write_sync include/linux/fs.h:2663 [inline]
btrfs_do_write_iter+0x6a9/0x840 fs/btrfs/file.c:1473
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x629/0xba0 fs/read_write.c:688
ksys_write+0x156/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a0bdece59
RSP: 002b:00007f5a0b446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5a0c065fa0 RCX: 00007f5a0bdece59
RDX: 000000000000029f RSI: 0000200000
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Take mmap_lock in zap_pages()
zap_vma_range() requires the owning mm's mmap_lock to be held.
Taking mmap_read_lock under arena->lock would AB-BA against
arena_vm_close() and arena_map_mmap(), both of which run with
mmap_write_lock held and then acquire arena->lock. Instead drop
arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and
re-resolve the vma via find_vma() since it may have been unmapped or
replaced while waiting.
Track processed vmls with a per-call generation in vml->zap_gen and
serialize zap_pages() callers with a new arena->zap_mutex so
concurrent callers on different uaddr ranges do not mark each other's
vmls processed before the zap is done. |
| In the Linux kernel, the following vulnerability has been resolved:
media: uvcvideo: Fix deadlock if uvc_status_stop is called from async_ctrl.work
If a UVC camera has an asynchronous control, uvc_status_stop may be
called from async_ctrl.work:
uvc_ctrl_status_event_work()
uvc_ctrl_status_event()
uvc_ctrl_clear_handle()
uvc_pm_put()
uvc_status_put()
uvc_status_stop()
cancel_work_sync()
This will cause a deadlock, since cancel_work_sync will wait for
uvc_ctrl_status_event_work to complete before returning.
Fix this by returning early from uvc_status_stop if we are currently in
the work function. flush_status now remains false until uvc_status_start
is called again, ensuring that uvc_ctrl_status_event_work won't resubmit
the URB. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: mpi3mr: Fix potential deadlock in mpi3mr_fault_uevent_emit
mpi3mr_fault_uevent_emit() runs from the fault watchdog and reset paths
where host I/O may already be blocked. GFP_KERNEL allocations here, both
the local kzalloc_obj() and the ones inside kobject_uevent_env() itself,
can trigger reclaim that waits on that blocked I/O and deadlock.
Use memalloc_noio_save()/restore() to cover the whole call instead of
just the local allocation. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: fix deadlock between metadata writeback and transaction commit
When writing out metadata extent buffers in a zoned filesystem,
btree_writepages() holds fs_info->zoned_meta_io_lock across the whole
writeback loop, including the call to btrfs_check_meta_write_pointer() ->
check_bg_is_active().
For the tree-log block group, check_bg_is_active() may fail to activate
the zone and fall back to btrfs_zone_finish_one_bg() to free an active
zone. That path waits for the running transaction to commit while still
holding zoned_meta_io_lock, but the committer needs that same lock to
write out the tree extents, so the two tasks deadlock:
Task A (kworker, metadata writeback) Task B (fsstress, transaction commit)
------------------------------------ -------------------------------------
wb_workfn() btrfs_commit_transaction(T)
btree_writepages() btrfs_write_and_wait_transaction()
btrfs_zoned_meta_io_lock() btrfs_write_marked_extents()
btrfs_check_meta_write_pointer() btree_writepages()
check_bg_is_active() [treelog_bg] btrfs_zoned_meta_io_lock()
btrfs_zone_finish_one_bg() <blocks on zoned_meta_io_lock,
btrfs_zone_finish() held by Task A>
do_zone_finish()
btrfs_inc_block_group_ro()
btrfs_wait_for_commit()
<blocks waiting for commit
of transaction T, done by
Task B>
The sibling branch in check_bg_is_active() already drops zoned_meta_io_lock
around do_zone_finish() for this exact reason. Do the same in the tree-log
branch: release the lock around btrfs_zone_finish_one_bg() and re-acquire
it afterwards. The lock only protects fs_info->active_{meta,system}_bg,
which this branch does not touch, and ctx->zoned_bg keeps a reference to
the block group across the unlock, so nothing is lost while the lock
is dropped.
This hang occasionally reproduces with fstests generic/475 on a zoned
btrfs filesystem. |
